A Cytokine Network Balance Influences the Fate of Leishmania (Viannia) braziliensis Infection in a Cutaneous Leishmaniasis Hamster Model

The golden hamster is a suitable model for studying cutaneous leishmaniasis (CL) due to Leishmania (Viannia) braziliensis. Immunopathological mechanisms are well established in the L. (L.) major-mouse model, in which IL-4 instructs a Th2 response towards progressive infection. In the present study, we evaluated the natural history of L. braziliensis infection from its first stages up to lesion establishment, with the aim of identifying immunological parameters associated with the disease outcome and parasitism fate. To this end, hamsters infected with 10⁴, 10⁵, or 10⁶ promastigotes were monitored during the first hours (4h, 24h), early (15 days, 30 days) and late (50 days) post-infection (pi) phases. Cytokines, iNOS and arginase gene expression were quantified in the established lesions by reverse transcription-quantitative PCR. Compared to the 10⁵ or 10⁶ groups, 10⁴ animals presented lower lesions sizes, less tissue damage, and lower IgG levels. Basal gene expression in normal skin was high for TGF-β, and intermediary for TNF, IL-6, and IL-4. At 4hpi, no cytokine induction was observed in the 10⁴ group, while an upregulation of IL-6, IL-10, and IL-4 was observed in the 10⁶ group. At 15dpi, lesion appearance was accompanied by an increased expression of all assessed cytokines, markedly in the 10⁵ and 10⁶ groups. Upregulation of all investigated cytokines was observed in the late phase, although less expressive in the 10⁴ group. IFN-γ was the depending variable influencing tissue damage, while IL-6 was associated to parasite load. The network correlating gene expression and clinical and laboratorial parameters indicated inoculum-independent associations at 15 and 30dpi. A strong positive network correlation was observed in the 10⁴ group, but not in the 10⁵ or 10⁶ groups. In conclusion, IL-4, IL-6, IL-10, and TGF-β are linked o L. braziliensis progression. However, a balanced cytokine network is the key for an immune response able to reduce the ongoing infection and reduce pathological damage.

An evaluation of p16(INK4a) expression in cervical intraepithelial neoplasia specimens, including women with HIV-1

Although several studies have evaluated the role of p16(INK4a) as a diagnostic marker of cervical intraepithelial neoplasia (CIN) and its association with disease progression, studies regarding the role of p16(INK4a) in human immunodeficiency virus (HIV)-infected patients remain scarce. The present study was designed to determine the potential utility of p16(INK4a) as a diagnostic marker for CIN and invasive cervical cancer in HIV-positive and negative cervical specimens. An immunohistochemical analysis of p16(INK4a) was performed in 326 cervical tissue microarray specimens. Performance indicators were calculated and compared using receiving operating characteristics curve (ROC)/area under the curve. In HIV-1-negative women, the percentage of cells that was positive for p16(INK4a) expression was significantly correlated with the severity of CIN (p < 0.0001). A ROC curve with a cut-off value of 55.28% resulted in a sensitivity of 89%, a specificity of 81%, a positive predictive value of 91% and a negative predictive value of 78%. HIV-seropositive women exhibited decreased expression of p16(INK4a) in CIN2-3 specimens compared with HIV-negative specimens (p = 0.031). The ROC data underscore the potential utility of p16(INK4a) under defined conditions as a diagnostic marker for CIN 2-3 staging and invasive cervical cancer. HIV-1 infection, however, is associated with relatively reduced p16(INK4a) expression in CIN 2-3.

SYBR Green-based real-time PCR targeting kinetoplast DNA can be used to discriminate between the main etiologic agents of Brazilian cutaneous and visceral leishmaniases

BACKGROUND

Leishmaniases control has been hampered by the unavailability of rapid detection methods and the lack of suitable therapeutic and prophylactic measures. Accurate diagnosis, which can distinguish between Leishmania isolates, is essential for conducting appropriate prognosis, therapy and epidemiology. Molecular methods are currently being employed to detect Leishmania infection and categorize the parasites up to genus, complex or species level. Real-time PCR offers several advantages over traditional PCR, including faster processing time, higher sensitivity and decreased contamination risk.

RESULTS

A SYBR Green real-time PCR targeting the conserved region of kinetoplast DNA minicircles was able to differentiate between Leishmania subgenera. A panel of reference strains representing subgenera Leishmania and Viannia was evaluated by the derivative dissociation curve analyses of the amplified fragment. Distinct values for the average melting temperature were observed, being 78.95 °C ± 0.01 and 77.36 °C ± 0.02 for Leishmania and Viannia, respectively (p < 0.05). Using the Neighbor-Joining method and Kimura 2-parameters, the alignment of 12 sequences from the amplified conserved minicircles segment grouped together L. (V.) braziliensis and L. (V.) shawii with a bootstrap value of 100%; while for L. (L.) infantum and L. (L.) amazonensis, two groups were formed with bootstrap values of 100% and 62%, respectively. The lower dissociation temperature observed for the subgenus Viannia amplicons could be due to a lower proportion of guanine/cytosine sites (43.6%) when compared to species from subgenus Leishmania (average of 48.4%). The method was validated with 30 clinical specimens from visceral or cutaneous leishmaniases patients living in Brazil and also with DNA samples from naturally infected Lutzomyia spp. captured in two Brazilian localities.

CONCLUSIONS

For all tested samples, a characteristic amplicon melting profile was evidenced for each Leishmania subgenus, corroborating the data from reference strains. Therefore, the analysis of thermal dissociation curves targeting the conserved kinetoplast DNA minicircles region is able to provide a rapid and reliable method to identify the main etiologic agents of cutaneous and visceral leishmaniases in endemic regions of Brazil.

Effects of ultraviolet radiation on human cutaneous nerve fibres

Due to an increasing number of skin diseases as a result of exposure to ultraviolet (UV) radiation, it is necessary to evaluate the effectiveness of new skin care formulations with broad-spectrum sunscreens.

OBJECTIVES

This study aims to assess the status of nerve fibres in healthy human skin, to quantify effects of UV radiation on nerve endings, and to evaluate neuroprotective effects of new skin care formulations against UV exposure damage.

METHODS

Samples were obtained from 34 female patients enrolled for plastic surgery and were immediately treated (10 min) with three emulsions: Cream 1, Cream 2 (placebo) and a sunscreen with sun protection factor 15 (SPF15). Control samples and those treated with the cream emulsions were exposed to UVA and UVB for 60 min. Nerve fibres were identified by immunofluorescence using a monoclonal antibody (anti-human CD56/NCAM). Cell damage was assessed by image analysis.

RESULTS

Several cellular nervous structures were identified in the skin samples, including free nerve endings. UVA and UVB significantly decreased (40-60%) density of nerve endings in the control samples and those treated with placebo (Cream 2) or SPF15 (all P < 0.001). Cream 1 completely blocked effects of UV radiation on nerve endings (P > 0.05 vs. control).

CONCLUSIONS

Quantification of cell damage induced by UV radiation provides useful information for identification of new skin care compounds with neuroprotective properties.

Immune factors involved in the cervical immune response in the HIV/HPV co-infection

AIMS

Immune factors influencing the progression of cervical intraepithelial neoplasia (CIN) to cancer remain poorly defined. This study investigates the expression of RANTES, MIP1alpha, COX1, COX2, STAT3, TGFbetaRI, IL10R, TNFalphaRII and TLR4 in the cervical immune response in HIV/HPV (human papillomavirus) co-infected women.

METHODS

Cervical biopsies of 36 patients were assayed by immunohistochemistry, and the Ventana Benchmark System was used for HIV-nef detection.

RESULTS

Cervices from HIV-positive patients exhibited nef in cells mainly around blood vessels, and showed a decreased expression of all the immune factors tested except IL10R and STAT3, while RANTES (5.54 cells/mm(2)) was highly expressed in comparison with controls (1.41 cells/mm(2), p = 0.028). COX1 was decreased in the HIV/HPV- (0.32 cells/mm(2), p = 0.017) and HPV-infected patients (0.21 cells/mm(2), p = 0.015) compared with controls (3.28 cells/mm(2)).

CONCLUSIONS

It is suggested that RANTES in HIV/HPV co-infection may influence the development of CIN leading to progression to cervical cancer.

Liver injury and viremia in mice infected with dengue-2 virus

The goal of this study was to test the feasibility of BALB/c mice as an experimental model in the study of dengue disease. BALB/c mice were intraperitoneal infected with DENV-2 obtained from a human patient. Histopathological analysis of infected animals revealed liver injury with viral antigens detection. In initial stages, the most prominent lesions were vacuolization and diffuse steatosis in hepatocytes. Serum levels of ALT and AST increased progressively, reaching the highest values 7 days p.i. and decreasing at the 14th day. Since levels of circulating virus were very low, viremia was analyzed in C6/36 cells. Virus presence was detected by ultrastructural analysis, confirmed by RT-PCR assays. Period of viremia was analyzed by flow cytometry with cells incubated with mouse-infected sera collected in different days, revealing peak virus levels at the 7th day p.i. All such data correlate to the development of the disease described in humans.

A comparison of horse-race, bingo, and video poker gamblers in Brazilian gambling settings

In the present study Brazilian gamblers from different settings were compared on sociodemographic characteristics, gambling the behavior, and use of drugs. The SOGS was administered to 171 subjects at bingo (BG), video poker (VP), and horse-racing clubs (HR) of São Paulo. BG concentrated most women, VP the youngest and single gamblers, and HR the lowest income subjects. More VP than HR or BG gamblers reported taking time off work to gamble, as well as returning another day to win back lost money. They also had a higher number of scorable responses on the SOGS. The differences observed suggest that VP gamblers bear a greater risk of developing a pathological gambling pattern. The authors suggest that measures should be taken aimed at the prevention of pathological gambling, particularly among the young population of video poker gamblers.

Pathological and nonpathological gamblers: a survey in gambling settings

In this first study on gambling in Brazil, pathological and non-pathological gamblers were surveyed at three bingo clubs, one video poker club, and one horse-racing club in São Paulo. The South Oaks Gambling Screen and a questionnaire were administered to 171 subjects. When compared to nonpathological gamblers, a significantly higher proportion of pathological gamblers played cards, horse races, video poker, and dice in their lifetime. The two groups were similar with respect to socially acceptable games such as lotteries, bingo, sports, and the stock market. No significant differences were observed in drug consumption except for a higher lifetime consumption of tobacco among pathological gamblers. Only 4.9% of the gamblers sought help for gambling-related problems, suggesting that gambling is not generally perceived as a mental health problem by these subjects.

Evaluation of the stability and immunogenicity of autoclaved and nonautoclaved preparations of a vaccine against American tegumentary leishmaniasis

This study was designed to evaluate the immunogenicity of autoclaved and nonautoclaved preparations of a vaccine composed of whole antigens from killed promastigotes of Leishmania amazonensis. Leishmanin skin-test (LST)-negative volunteers were immunized with either autoclaved or nonautoclaved vaccine preparations (32 and 36 subjects, respectively) that had been maintained at 4 degrees C for one year before the onset of this trial. Immunological tests were performed two days before and 40 days after vaccination. The LST conversion rates induced by the autoclaved and nonautoclaved vaccines were significantly different: 59% and 83%, respectively. Leishmania antigen-stimulated proliferative responses of peripheral blood mononuclear cells (PBMC) were significantly higher after vaccination than before vaccination in both groups. The CD8+ subset was predominant over the CD4+ subset among the leishmania-reactive cells after vaccination in both groups. The production of IFN-gamma by the leishmania antigen-stimulated PBMC was significantly higher after vaccination than before vaccination in the group receiving the nonautoclaved vaccine but not in the autoclaved vaccine group. IL-2 was found both before and after vaccination with no differences between its levels in these time points in either group. IL-4 was not detected for either group during the study period.

Changes in metabolism of inorganic polyphosphate in rat tissues and human cells during development and apoptosis

Age-dependent studies show that the amount of inorganic polyphosphate in rat brain strongly increases after birth. Maximal levels were found in 12-months old animals. Thereafter, the concentration of total polyphosphate decreases to about 50%. This decrease in the concentration of total polyphosphate is due to a decrease in the amount of insoluble, long-chain polyphosphates. The amount of soluble, long-chain polyphosphates does not change significantly in the course of ageing. In rat embryos and newborns, mainly soluble polyphosphates could be detected. In rat liver, the age-dependent changes are less pronounced. The changes in polyphosphate level are accompanied by changes in exopolyphosphatase activity, which degrades the polymers to orthophosphate; highest enzyme activities were found when the polyphosphate level was low. Induction of apoptosis in the human leukemic cell line HL-60 by actinomycin D results in degradation of long polyphosphate chains. The total polyphosphate content does not change significantly in apoptotic cells.

A novel method for determination of inorganic polyphosphates using the fluorescent dye fura-2

A method for determining inorganic polyphosphate, which is based on the Mn(2+)-induced quenching of the fluorescence of the calcium indicator fura-2, is described. The effect of Mn2+ ions on fura-2 fluorescence is gradually abolished in the presence of increasing concentrations of polyphosphate; this allows the quantification both of synthetic polyphosphates and of the naturally occurring polymer isolated from tissues or cells. The described method has some advantages compared to conventional procedures for detection of polyphosphates based on the metachromatic effect on toluidine blue. It can be applied for the determination of pyrophosphate, tripolyphosphate and other short-chain polyphosphates not detectable by toluidine blue and it can be used for measurement both of pyrophosphatase and exopolyphosphatase activity.

T-cell responsiveness of American cutaneous leishmaniasis patients to purified Leishmania pifanoi amastigote antigens and Leishmania braziliensis promastigote antigens: immunologic patterns associated with cure

Patients suffering from American cutaneous leishmaniasis were studied before therapy (active lesion) and at the end of therapy (cured patients). Assays of lymphocyte proliferative responses of peripheral blood mononuclear cells induced in vitro by Leishmania braziliensis promastigote antigens (Lb) or by three proteins (A-2/P-2, P-4, and P-8) derived from Leishmania pifanoi amastigotes were performed. Antigen-stimulated cells were harvested for CD4 and CD8 phenotype analysis and the levels of gamma interferon (IFN-gamma), interleukin 2 (IL-2) and interleukin 4 (IL-4) produced were also determined. Results show two different patterns of Lb-induced T cell responses: (a) predominance of responding CD4+ cells and mixed type 1 and type 2 cytokine production (IFN-gamma, IL-2, and IL-4) during the active disease, (b) similar proportions of responding CD4+ and CD8+ cells and type 1 cytokine production (presence of IFN-gamma and IL-2 and very low IL-4) at the end of therapy (healed lesions). Thus, this last pattern is probably associated with a beneficial T cell response. The A-2/P-2 amastigote cysteine proteinase provided only marginal (s.i. approximately or = 2.5) T cell stimulation in 25% of patients studied; in contrast, the L. pifanoi P-4 and P-8 amastigote antigens induced significant stimulation (s.i. approximately or = 5) in approximately 50% of the patients. In comparison to Lb-stimulated cultures, lower proliferative responses of T lymphocytes to P-4 or P-8 were observed. However, the P-4- or P-8-stimulated cultures had similar percentages of reactive CD4+ and CD8+ cells, as well as type 1 cytokines (presence of IFN-gamma and IL-2, and low levels or absence of IL-4) in the supernatants both before and at the end of therapy. The consistent induction of apparently beneficial T cell responses by the P-4 and P-8 amastigote glycoproteins points to the possibility that these molecules be considered as candidates for future defined vaccines against leishmaniasis.

Cytochemical analysis of the content of chicken thrombocytes vacuoles

The content of the large vacuoles present in chicken thrombocytes was analyzed by the use of cytochemical techniques which indicated the presence of basic proteins, unsaturated fatty acids, sugars rich in viccinal hydroxyl groups, linked to proteins or lipids and acid phosphatase. These substances perform one of the most conspicuous functions of these cells, which is phagocytosis. In addition, thrombocytes are committed to hemostasis. Both functions make these cells similar to human platelets, even though having different origins and morphologic characteristics. The large vacuoles described are connected to the open canalicular system (OCS) and together with other cellular structures they contribute to the endocytic system.