Soil erosion after forest fires: evaluation of mitigation measures applied to drainage channels in the northwest of Portugal

The development and implementation of measures which promote the reduction of the impacts of forest fires on soils is imperative and should be part of any strategy for forest and soil preservation and recovery, especially considering the actual scenario of continuous growth in the number of fires and burnt area. Consequently, with the dendrocaustologic reality that has characterized the Portuguese mainland in recent decades, a research project promoted by the Center for the Study of Geography and Spatial Planning (CEGOT) was implemented with the objective of applying several erosion mitigation measures in a burned area of the Peneda-Geres National Park in NW Portugal. This paper therefore seeks to present the measures applied in the study area within the project Soil Protec, relating to triggered channel processes and the results of preliminary observations concerning the evaluation of the effectiveness of erosion mitigation measures implemented, as well as their cost/benefit ratio.

Growth curves of Leishmania braziliensis braziliensis Promastigotes and surface antigen expression before and after adaptation to Schneider's drosophila medium as assessed by anti-Leishmania human sera

Leishmania braziliensis braziliensis(MHOM/BR/75/M2903) was grown in Schneider's Drosophila medium. In one set of experiments promastigotes were already adapted to the medium by means of serial passages whereas in the second cells were grown in a biphasic medium and transfered to the liquid. Growth was more abundant for culture medium adapted cells; degenerate cells in small numbers as well as dead ones were present from day 5 for promastigotes adapted to liquid medium and from day 3 for newly adapted cells. Synthesis of surface antigens differed according to length of cell culture as assessed by the titer of five mucocutaneous leishmaniasis sera on subsequent days. Five days of culture for cells already adapted to the culture medium and 3 days for newly adapted ones were judged to be the best for the preparation of immunofluorescence antigens.

Acquisition and data analysis related to changes in some forest soils properties after prescribed fire action

Controlled fires in forest areas are frequently used in most Mediterranean countries as a preventive technique to avoid severe wildfires in summer season. In Portugal, this forest management method of fuel mass availability is also used and has shown to be beneficial as annual statistical reports confirm that the decrease of wildfires occurrence have a direct relationship with the controlled fire practice. However prescribed fire can have serious side effects in some forest soil properties. This work shows the changes that occurred in some forest soils properties after a prescribed fire action. The experiments were carried out in soil cover over a natural site of Andaluzitic schist, in Gramelas, Caminha, Portugal, that had not been burn for four years. The composed soil samples were collected from five plots at three different layers (0-3cm, 3-6cm and 6-18cm) during a three-year monitoring period after the prescribed burning. Principal Component Analysis was used to reach the presented conclusions.

Soil attributes dynamics evaluation after prescribed burning practice in northwestern Portugal forest

The Portuguese northern forests are often and severely affected by wildfires during the summer season. These occurrences affect significant and rudely all ecosystems, namely soil, fauna and flora. Preventive actions such as prescribed burnings and clear-cut logging are frequently used and have showed a significant reduction of the natural wildfires occurrences. In Portugal, and due to some technical and operational conditions, prescribed burnings in forests are the most common preventive action used to reduce the existing fuel hazard. The overall impacts of this preventive action on Portuguese ecosystems are complex and not fully understood. This work reports to the study of a prescribed burning impact in soil chemical properties, namely pH, humidity and organic matter, by monitoring the soil self-recovery capacity. The experiments were carried out in soil cover over a natural site of Andaluzitic schist, in Gramelas, Caminha, Portugal, who was able to maintain itself intact from prescribed burnings from four years. The composed soil samples were collected from five plots at three different layers (0-3cm, 3-6cm and 6-18cm) 1 day before prescribed fire and after the prescribed fire. The results have shown that the dynamic equilibrium in soil was affected significantly.

Reinfection after treatment of schistosomiasis: environment or "predisposition"?

Although very efficient for the control of morbidity due to S. mansoni in individual patients, chemotherapy has not proven successful in the management of transmission within hyperendemic areas when used alone, even if repeated at short intervals. Consequently, a great deal of effort has been expended toward immunologic investigation and development of a specific vaccine. Based upon a study of a group of children (5-14 years) from the state of Alagoas, the author demonstrates that the outcome one year after chemotherapy depends essentially on the "risk rating" of the area of domicile. A regression analysis did not reveal significant correlation to neither age, sex or initial egg counts. Although the study was not designed to reveal individual variations in the immune status, it is postulated that putative differences in genetic make-up are irrelevant in terms of large-scale intervention. Since morbidity due to S. mansoni has substantially declined during the last two or three decades, a control policy based on vaccination can only be justified if high levels of protective immunity can be attained. At any rate, such a vaccine will have to be administered in early childhood (preferably below the age of three). It can also be demonstrated that immunization in adolescence or adulthood serves no purpose whatsoever. The author is convinced that environmental intervention, usually dismissed as unrealistic in terms of the developing countries, is not only feasible, if done on a selective basis, but prioritary.

Schistosoma mansoni: acquired immunity in mice after the use of oxamniquine at the evolutive skin and pulmonary phases

Mice infected with 350 cercariae of Schistosoma mansoni (LE strain) were treated with oxamniquine, at the dose of 400 mg/kg, 24, 48, 72, and 96 h after infection. Forty days after the treatment, the animals were submitted to a challenge infection with 80 cercariae, through the abdominal and ear skins. The number of immature worms in the animal groups treated 24 and 96 h after the first infection was found to be lower than that in the control group, thus showing that the death of schisto-somes by chemotherapy, at the skin and pulmonary phases, causes an acquired resistance state.

Rheo-optical characterization of liquid crystalline acetoxypropylcellulose melt undergoing large shear flow and relaxation after flow cessation

The rheological and structural characteristics of acetoxypropylcellulose (APC) nematic melt are studied at shear rates ranging from 10 s(-1) to 1000 s(-1) which are relevant to extrusion based processes. APC shows a monotonic shear thinning behavior over the range of shear rates tested. The negative extrudate-swell shows a minimum when a critical shear rate (gamma) over dot(c) is reached. For shear rates smaller than (gamma) over dot(c), the flow-induced texture consists of two set of bands aligned parallel and normal to the flow direction. At shear rates larger than (gamma) over dot(c), the flow induced texture is reminiscent of a 2 fluids structure. Close to the shearing walls, domains elongated along the flow direction and stacked along the vorticity are imaged with POM, whereas SALS patterns indicate that the bulk of the sheared APC is made of elliptical domains oriented along the vorticity. No full nematic alignment is achieved at the largest shear rate tested. Below (gamma) over dot(c), the stress relaxation is described by a stretched exponential. Above (gamma) over dot(c), the stress relaxation is described by a fast and a slow process. The latter coincides with the growth of normal bands thicknesses, as the APC texture after flow cessation consists of two types of bands with parallel and normal orientations relative to the flow direction. Both bands thicknesses do not depend on the applied shear rate, in contrast to their orientation. (C) 2015 Elsevier Ltd. All rights reserved.

Schistosoma mansoni: evaluation of the activity of oxamniquine on schistosomules, at 24 hours after infection

Mice transcutaneously infected with about 400 cercariae were submitted to treatment with oxamniquine (400 mg/kg), 24 hours after infection. The recovery of schistosomules, at 4, 24, 48 and 72 hours and 35 days after treatment, showed the activity of the drug on the parasites, thus practically preventing their migration from the skin to the lungs. Worm recovery performed in the lungs (96 hours after treatment) showed recovery means of 0.6 worms/mouse in the treated group and 53.8 in the control group (untreated). The perfusion of the portal system carried out at 35 days after treatment clearly showed the elimination of all the parasites in the treated group, whereas a recovery mean of 144.7 worms/mouse was detected in the control group (untreated). These findings confirm the efficacy of oxamniquine at the skin phase of infection, and also show similarity with the immunization method that uses irradiated cercariae. The practical application of these findings in the medical clinic is discussed too

Immune reconstitution after autologous hematopoietic stem cell transplantation��

Abstract The investigation of the web of relationships between the different elements of the immune system has proven instrumental to better understand this complex biological system. This is particularly true in the case of the interactions between B and T lymphocytes, both during cellular development and at the stage of cellular effectors functions. The understanding of the B���T cells interdependency and the possibility to manipulate this relationship may be directly applicable to situations where immunity is deficient, as is the case of cancer or immune suppression after radio and chemotherapy. The work presented here started with the development of a novel and accurate tool to directly assess the diversity of the cellular repertoire (Chapter III). Contractions of T cell receptor diversity have been related with a deficient immune status. This method uses gene chips platforms where nucleic acids coding for lymphocyte receptors are hybridized and is based on the fact that the frequency of hybridization of nucleic acids to the oligonucleotides on a gene chip varies in direct proportion to diversity. Subsequently, and using this new method and other techniques of cell quantification I examined, in an animal model, the role that polyclonal B cells and immunoglobulin exert upon T cell development in the thymus, specifically on the acquisition of a broader repertoire diversity by the T cell receptors (Chapter IV and V). The hypothesis tested was if the presence of more diverse peptides in the thymus, namely polyclonal immunoglobulin, would induce the generation of more diverse T cells precursors. The results obtained demonstrated that the diversity of the T cell compartment is increased by the presence of polyclonal immunoglobulin. Polyclonal immunoglobulin, and particularly the Fab fragments of the molecule, represent the most diverse self-molecules in the body and its peptides are presented by antigen presenting cells to precursor T cells in the thymus during its development. This probably contributes significantly to the generation of receptor diversity. Furthermore, we also demonstrated that a more diverse repertoire of T lymphocytes is associated with a more effective and robust T cell immune function in vivo, as mice with a more diverse T cell receptors reject minor histocompatiblility discordant skin grafts faster than mice with a shrunken T cell receptor repertoire (Chapter V). We believe that a broader T cell receptor diversity allows a more efficient recognition and rejection of a higher range of external and internal aggressions. In this work it is demonstrated that a reduction of TCR diversity by thymectomy in wild type mice significantly increased survival of H-Y incompatible skin grafts, indicating decrease on T cell function. In addiction reconstitution of T-cell diversity in mice with a decreased T cell repertoire diversity with immunoglobulin Fab fragments, lead to a increase on TCR diversity and to a significantly decreased survival of the skin grafts (Chapter V). These results strongly suggest that increases on T cell repertoire diversity contribute to improvement of T cell function. Our results may have important implications on therapy and immune reconstitution in the context of AIDS, cancer, autoimmunity and post myeloablative treatments. Based on the previous results, we tested the clinical hypothesis that patients with haematological malignancies subjected to stem cell transplantation who recovered a robust immune system would have a better survival compared to patients who did not recover such a robust immune system. This study was undertaken by the examination of the progression and overall survival of 42 patients with mantle cell non-Hodgkin lymphoma receiving autologous hematopoietic stem cell transplantation (Chapter VI). The results obtained show that patients who recovered higher numbers of lymphocytes soon after autologous transplantation had a statistically significantly longer progression free and overall survivals. These results demonstrate the positive impact that a more robust immune system reconstitution after stem cell transplantation may have upon the survival of patients with haematological malignancies. In a similar clinical research framework, this dissertation also includes the study of the impact of recovering normal serum levels of polyclonal immunoglobulin on the survival of patients with another B cell haematological malignancy, multiple myeloma, after autologous stem cell transplantation (Chapter VII). The relapse free survival of the 110 patients with multiple myeloma analysed was associated with their ability to recover normal serum levels of the polyclonal compartment of immunoglobulin. These results suggest again the important effect of polyclonal immunoglobulin for the (re)generation of the immune competence. We also studied the impact of a robust immunity for the response to treatment with the antibody anti CD20, rituximab, in patients with non- Hodgkin���s lymphoma (NHL) (Chapter VIII). Patients with higher absolute counts of CD4+ T lymphocytes respond better (in terms of longer progression free survival) to rituximab compared to patients with lower number of CD4+ T lymphocytes. These observations highlight again the fact that a competent immune system is required for the clinical benefit of rituximab therapy in NHL patients. In conclusion, the work presented in this dissertation demonstrates, for the first time, that diverse B cells and polyclonal immunoglobulin promote T cell diversification in the thymus and improve T lymphocyte function. Also, it shows that in the setting of immune reconstitution, as after autologous stem cell transplantation for mantle cell lymphoma and in the setting of immune therapy for NHL, the absolute lymphocyte counts are an independent factor predicting progression free and overall survival. These results can have an important application in the clinical practice since the majority of the current treatments for cancer are immunosuppressive and implicate a subsequent immune recovery. Also, the effects of a number of antineoplastic treatments, including biological agents, depend on the immune system activity. In this way, studies similar to the ones presented here, where methods to improve the immune reconstitution are examined, may prove to be instrumental for a better understanding of the immune system and to guide more efficient treatment options and the design of future clinical trials. Resumo O estudo da rede de inter-rela����es entre os diversos elementos do sistema immune tem-se mostrado um instrumento essencial para uma melhor compreens��o deste complexo sistema biol��gico. Tal �� particularmente verdade no caso das interac����es entre os linf��citos B e T, quer durante o desenvolvimento celular, quer ao n��vel das fun����es celulares efectoras. A compreens��o da interdepend��ncia entre linf��citos B e T e a possibilidade de manipular esta rela����o pode ser directamente aplic��vel a situa����es em que a imunidade est�� deficiente, como �� o caso das doen��as neopl��sicas ou da imunossupress��o ap��s radio ou quimioterapia. O trabalho apresentado nesta disserta����o iniciou-se com o desenvolvimento de um novo m��todo laboratorial para medir directamente a diversidade do report��rio celular (Cap��tulo III). Redu����es da diversidade do report��rio dos receptores de c��lulas T t��m sido relacionadas com um estado de imunodefici��ncia. O m��todo desenvolvido utiliza ���gene chips���, aos quais hibridizam os ��cidos nucleicos codificantes das cadeias proteicas dos receptores linfocit��rios. A diversidade �� calculada com base na frequ��ncia de hibridiza����o do ��cido nucleico da amostra aos oligonucle��tidos presentes no ���gene chip���. De seguida, e utilizando este novo m��todo e outras t��cnicas de quantifica����o celular examinei, num modelo animal, o papel que as c��lulas policlonais B e a imunoglobulina exercem sobre o desenvolvimento linfocit��rio T no timo, especificamente na aquisi����o de um report��rio diverso de receptores T (Cap��tulos IV e V). Testei, ent��o, a hip��tese de que a presen��a no timo de p��ptidos mais diversos, como a imunoglobulna policlonal, induzisse a g��nese de precursores T mais diversos. Demonstr��mos que a diversidade do compartimento T �� aumentado pela presen��a de imunoglobulina policlonal. A imunoglobulina policlonal, e particularmente os fragmentos Fab desta mol��cula, representam as mol��culas aut��logas mais diversas presentes nos organismos vertebrados. Estes p��ptidos s��o apresentados por c��lulas apresentadoras de antig��nio ��s c��lulas precursoras T no timo, durante o desenvolvimento celular T. Tal, provavelmente, contribui para a g��nese da diversidade dos receptores. Tamb��m demonstr��mos que a presen��a de um report��rio mais diverso de linf��citos T se associa a um incremento da fun����o imunol��gica T in vivo. Uma diversidade de receptores T mais extensa parece permitir um reconhecimento e rejei����o mais eficientes de um maior n��mero de agressores internos e externos. Demonstr��mos que ratinhos com receptores de c��lulas T (RCT) com maior diversidade rejeitam transplantes cut��neos discordantes para antig��nios minor de histocompatibilidade mais rapidamente do que ratinhos com um menor report��rio T (Cap��tulo V). Por outro lado, uma redu����o da diversidade do RCT, causada por timectomia de ratinhos de estirpes selvagens, mostrou aumentar significativamente a sobreviv��ncia de transplantes cut��neos incompat��veis para o antig��nio H-Y (antig��nio minor de histocompatibilidade), indicando uma diminui����o da fun����o linfocit��ria T. Al��m disso, a reconstitui����o da diversidade dos linf��citos T em ratinhos com uma diversidade de report��rio T diminu��da, induzida pela administra����o de fragmentos Fab de imunoglobulina, conduz a um aumento da diversidade dos RCT e a uma diminui����o significativa da sobreviv��ncia dos enxertos cut��neos (Cap��tulo V). Estes resultados sugerem que o aumento do report��rio de c��lulas T contribui para uma melhoria das fun����es celulares T e poder��o ter implica����es importantes na terap��utica e reconstituti����o imunol��gica em contexto de SIDA, neoplasias, autoimunidade e ap��s tratamentos mieloablativos. Baseado nos resultados anteriores, decidimos testar a hip��tese cl��nica de que doentes com neoplasias hematol��gicas sujeitos a transplanta����o de precursores hematopoi��ticos e com recupera����o imunol��gica precoce ap��s transplante teriam uma sobreviv��ncia mais longa do que doentes que n��o recuperassem t��o bem a sua imunidade. Analis��mos a sobreviv��ncia global e sobreviv��ncia sem doen��a de 42 doentes com linfoma n��o Hodgkin de c��lulas do manto sujeitos a transplante aut��logo de precursores hematopoi��ticos (Cap��tulo VI). Os resultados obtidos mostraram que os doentes que recuperaram contagens mais elevadas de linf��citos imediatamente ap��s o transplante aut��logo, apresentaram uma sobreviv��ncia global e sem progress��o mais longa do que doentes que n��o recuperaram contagens linfocit��rias t��o precocemente. Estes resultados demonstram o efeito positivo de uma reconstituti����o imunol��gica robusta ap��s transplante de presursores hematopoi��ticos, sobre a sobreviv��ncia de doentes com neoplasias hematol��gicas. Do mesmo modo, estud��mos o efeito que a recupera����o de n��veis s��ricos normais de imunoglobulina policlonal tem na sobreviv��ncia de doentes com outras neoplasias hematol��gicas de linf��citos B, como o mieloma m��ltiplo,ap��s transplante aut��logo de precursos hematopoi��ticos (Cap��tulo VII). A sobreviv��ncia livre de doen��a dos 110 doentes com mieloma m��ltiplo analizados est�� associada com a sua capacidade de recuperar n��veis s��ricos normais do compartmento policlonal de imunoglobulina. Estes resultados pioneiros indicam a import��ncia da imunoglobulina policlonal para a g��nese de compet��ncia imunol��gica. Tamb��m estud��mos o impacto de um sistema imunit��rio eficiente sobre a resposta ao tratamento com o anticorpo anti CD20, ituximab, em doentes com linfoma n��o Hodgkin (LNH) (Cap��tulo VIII). Os resultados mostram que doentes com valores mais elevados de linf��citos T CD4+ respondem melhor (em termos de maior sobrevida livre de doen��a) ao rituximab, do que doentes com valores mais baixos. Estas observa����es ilustram a necessidade de um sistema imunit��rio competente para o benef��cio cl��nico da terap��utica com rituximab em doentes com LNH. Em conclus��o, o trabalho apresentado nesta disserta����o demonstra que as c��lulas B e a imunoglobulina policlonal promovem a diversidade das c��lulas T no timo e melhoram a fun����o linfocit��ria T perif��rica. Concomitantemente, tamb��m demonstr��mos que, no contexto de reconstitui����o imune, por exemplo, ap��s transplante aut��logo de precursores hematopoi��ticos em doentes com linfomas de c��lulas do manto, o n��mero absoluto de linf��citos �� uma factor independente da sobreviv��ncia. Os resultados demonstram, tamb��m, a import��ncia dos valores de linfocitos T na resposta ao tratamento com rituximab no caso de doentes com LNH. O mesmo princ��pio se prova pelo facto de que doentes com mieloma m��ltiplo sujeitos a transplante aut��logo de precursores hematopoi��ticos que recuperam valores normais s��ricos de imunoglobulinas policlonais, terem melhores taxas de resposta em compara����o com doentes que n��o recuperam valores normais de imunoglobulinas policlonais. Estes resultados podem ter importantes aplica����es na pr��tica cl��nica dado que a maioria dos tratamentos de doen��as neopl��sicas implica imunossupress��o e, subsequente, recupera����o imunol��gica. Estes estudos podem ser um instrumento fundamental para uma melhor compreens��o do sistema imune e guiar uma escolha mais eficiente de op����es terap��uticas bem como contribuir para a concep����o de futuros estudos cl��nicos.

Schistosoma mansoni circulating polysaccharide and protein antigens recognized by sheep antisera in patients with different clinical forms of schistosomiasis before and after treatment

Two sheep antisera, one of which raised against polysaccharide (Po) and other against protein (Pt) components of Schistosoma mansoni adult worms, were assessed by ELISA for their ability to detect circulating parasite antigens in patients with different clinical forms of chronic schistosomiasis mansoni. The former antiserum detected parasite antigens in liver granulomata and the latter in renal glomeruli from schistosomiasis patients and mice experimentally infected with S. mansoni. In general, the levels and/or positivity rate of circulating antigens and specific IgG antibodies were significantly higher in patients with hepatointestinal (HI) and hepatosplenic (HS) forms than in mild intestinal (I) forms. An association between Po antigens and clinical features of the disease was observed, as the level of these antigens was low (137 ng/ml) as well as the positivity rate (7.9%) in patients with I forms; values that were intermediate (593 ng/ml and 33.3%) in those with HI forms, and high (1.563 ng/ml and 50.0%) in more severe HS forms. The Pt antigens were detected in the studied clinical forms not differing statistically but, the positivity rate was significantly higher in HS forms comparatively to I forms. The antisera studied revealed distinct circulating antigen profiles, and the prognostic value of Po and Pt antigens was suggested.

Autoantibodies before, during and after administration of recombinant interferon-alpha for chronic viral hepatitis

This study was undertaken to investigate the presence of autoantibodies in patients with chronic viral hepatitis B and C, before, during and after interferon-alpha (IFN-alpha) therapy and to study their relation to dose and type of IFN-alpha and response to treatment. Fifty patients with chronic hepatitis were divided in two groups, a control-group of 21 patients (10 type B and 11 type C) who were followed for 6 months without treatment and an IFN-group consisting of 29 patients (8 type B and 21 type C) who received IFN therapy for 6 months. Serum samples were tested for a range of antibodies at the start of the study, during therapy and at the end of the 6 month period. Antibodies tested for included: antinuclear, smooth muscle, antimitochondrial, parietal cell and thyroid microsomal. Four (8%) of the total patient group had autoantibodies at the beginning of the study (two in each group). During the follow-up period no patient in the control group developed antibodies compared with 3 (11%) patients in the treatment group. Autoantibodies developed in patients treated with higher doses of IFN and were found in those patients who tended to show a poor response to IFN-therapy. Further studies are needed to establish the relationship between poor response to IFN-alpha and development of autoantibodies.

Trypanosoma cruzi strains: behavior after passage into authoctonous or foreign species of triatomine (biological and biochemical patterns)

The behavior of T. cruzi strains from S. Felipe - BA (19 SF, 21 SF and 22 SF) classified as Type II Zymodeme 2, was investigated after passage through the authoctonous (P. megistus) and foreign vectors (T. infestans and R. prolixus). For each strain Swiss mice were infected: I - with blood forms (control); II - with metacyclic forms (MF) from P. megistus; III - with MF from T. infestans; IV - with MF from R. prolixus. Inocula: MF from the three species of triatomine, 60 to 120 days after feeding in infected mice, adjusted to 10 4. Biological behavior in mice (parasitemia, morphology, mortality, virulence and pathogenicity) after passage through triatomine was compared with data from the same strain in control mice. Isoenzymic electrophoresis (ASAT, ALAT, PGM, GPI) were also performed after culture into Warren medium. The three strains maintained the isoenzyme profiles (zymodeme 2), in the control groups and after passages through different species of triatomine. Biological characterization disclosed Type II strains patterns for all groups. An increased virulence was observed with the 22 SF strain isolated from P. megistus and T. infestans and higher levels of parasitemia and predominance of slender forms in mice inoculated with the 19 SF and 21 SF from these same species. Results indicate that the passage through the two species T. infestans and P. megistus had a positive influence on the virulence of the regional strains of S. Felipe, regardless of being autocthonous (P. megistus) or foreign to the area (T. infestans).

Measles antibody prevalence after mass immunization campaign in Niter��i, State of Rio de Janeiro, Brazil

Three months after a mass vaccination campaign (coverage: 100%) against measles a random seroepidemiological survey was carried out in students aged 1 to 19 years old in the Municipality of Niter��i, State of Rio de Janeiro. Blood samples were tested for measles antibodies by enzyme immunosorbent assay (EIA) and negative cases were tested again using hemagglutination inhibition (HI) and plaque reduction neutralization (PRN). Of the 798 samples tested by EIA, 718 (90.2%) were positive for measles antibodies. PRN test was more sensitive than EIA and HI in detecting measles specific antibodies. The total antibody prevalence increased from 90.2% to 93.2% when HI was employed in EIA negative specimens and to 98.9% when PRN was used. After the mass vaccination campaign a marked decrease in measles incidence was observed in the municipality studied, showing the effectiveness of the strategy used for measles control in developing countries.