Spatial dynamics of urban populations of Lutzomyia longipalpis (Diptera: Psychodidae) in Caxias, State of Maranhão, Brazil

Introduction In this paper, we report the ecology of Lutzomyia longipalpis in Caxias City, located in the eastern part of State of Maranhão, Brazil and highlight its seasonal and geographical distribution by environment. In addition, we discuss natural Leishmania infection and its relationship with visceral leishmaniasis. Methods Between September 2007 and August 2009, the collection of sandflies was performed using Center for Disease Control (CDC) light traps from 15 houses in 5 selected neighborhoods. Results Lutzomyia longipalpis was present in all zones of the city. We also found that Lu. longipalpis was regularly detected both inside and around the house, predominantly in outdoor areas. In urban areas, Lu. longipalpis was present in both the dry and rainy seasons, with a higher density present in the latter. One female specimen of Lu. longipalpis was observed to have natural Leishmania infection. Conclusions The presence of Lu. longipalpis was observed throughout the year during 2 seasonal periods, with a predominance in the rainy season. A low rate of natural Leishmania infection was observed in urban areas during the rainy season.

Schistosomiasis mansoni in urban Northeast Brazil: influence of rainfall regime on the population dynamics of Biomphalaria sp.

Introduction Our objective was to evaluate the influence of rainfall regime on the population dynamics of Biomphalaria in a potential urban focus of schistosomiasis in Aracaju, Brazil, during 2009-2010. Methods Snails were collected monthly and were counted, measured and identified; the level of infection and fecal contamination at the sampling sites was determined; rainfall data were obtained. Results High levels of fecal contamination were observed, and the abundance of Biomphalaria glabrata increased during the rainy and post-rainy seasons. The snails' size was variable, and infected snails were identified independently of rainfall. Conclusions These results provide evidence of anthropogenic and climate interference in an urban focus of schistosomiasis in the Aracaju metropolitan area.

Diversity and dynamics of airborne fungi in São Luis, State of Maranhão, Brazil

Introduction: This study aimed to identify airborne fungi in São Luis, Maranhão, Brazil, to determine the prevalent genera and to correlate these genera with the area and season. Methods: In total, 1,510 colony-forming units (CFUs) of airborne fungi were isolated from the north, south, east and west sides and from the center of the city from January to December 2007. The samples were collected on Petri dishes that were exposed to the fungi by the gravitational method. Results: Twenty genera of fungi were isolated; the most common were Aspergillus (33.5%), Penicillium (18.8%), Cladosporium (14.2%), Curvularia (10.6%) and Fusarium (7.6%). The CFUs of the fungi were statistically significant (p < 0.0001). Fungal biological diversity was present all year, without any large seasonal variations but with slight increases in May, August and September. Conclusions: The fungal genera identified in this study were correlated with natural systems and could be useful when evaluating the impact of environmental changes on the region.

Observations on dynamics of foraging hole construction of two leaf-feeding, soil-inhabiting Syntermes species (insecta: Isoptera) in an Amazonian Rainforest, Brazil

The intensity of construction of foraging access holes by two leaf-litter feeding, soil- inhabiting termite species, Syntermes molestus and Syntermes spinosus, in a Central Amazonian rain forest, was observed on consecutive nights for two weeks. Between 11 and 48 nest entrances per m2 were counted. Interaction between the two species was intense; some entrance holes were overtaken by the larger species during the observations; however, both species coexist in the area. A calculated minimum of 35 entrances/m2 is built every year by both species, emphasizing the importance of soil-burrowing termites for soil structure, aeration and water regime.

Observations on aquatic Macrophyte Dynamics In the Reservoir Of The Balbina Hydroelectric Powerplant, Amazonas State, Brazil

Between 1991 and 1995 aquatic macrophyte composition was observed in the lower part of the reservoir of the hydroelectric power plant of Balbina (Amazonas, Brazil). After closure of the dam in 1987, vegetation cover - mostly Eichhornia crassipes - was high, but was not quantified. After 1990 it declined rapidly with a characteristic succession pattern: Eichhornia ® Vincularia + Cyperaceae ® Salvinia. The Cyperaceae, and many other less dominant species, were mostly associated with drift wood, produced by the decomposing, emergent forest. Comparison of the chemical data of the Uatumã river before the construction of the dam (1983) with those of later years (1989 - 1995) suggests that the succession was the result of a relatively mild and short period of eutrophication, followed by declining nutrient levels. Annual variation of water levels, followed by aquatic and terrestrial decomposition of the marginal vegetation, may allow for the maintenance of relatively productive vegetation belts along the shore lines of islands and inundated stream valleys.

Soil mineral N dynamics beneath mixtures of leaves from legume and fruit trees in Central Amazonian multi-strata agroforests

Long term applications of leguminous green mulch could increase mineralizable nitrogen (N) beneath cupuaçu trees produced on the infertile acidic Ultisols and Oxisols of the Amazon Basin. However, low quality standing cupuaçu litter could interfere with green mulch N release and soil N mineralization. This study compared mineral N, total N, and microbial biomass N beneath cupuaçu trees grown in two different agroforestry systems, north of Manaus, Brazil, following seven years of different green mulch application rates. To test for net interactions between green mulch and cupuaçu litter, dried gliricidia and inga leaves were mixed with senescent cupuaçu leaves, surface applied to an Oxisol soil, and incubated in a greenhouse for 162 days. Leaf decomposition, N release and soil N mineralization were periodically measured in the mixed species litter treatments and compared to single species applications. The effect of legume biomass and cupuaçu litter on soil mineral N was additive implying that recommendations for green mulch applications to cupuaçu trees can be based on N dynamics of individual green mulch species. Results demonstrated that residue quality, not quantity, was the dominant factor affecting the rate of N release from leaves and soil N mineralization in a controlled environment. In the field, complex N cycling and other factors, including soil fauna, roots, and microclimatic effects, had a stronger influence on available soil N than residue quality.

Population Dynamics Modeling of Arapaima gigas

Pirarucu (Arapaima gigas) has been of the most important natural fishing resources of the Amazon region. Due to its economic importance, and the necessity to preserve the species hand, field research concerning the habits and behavior of the pirarucu has been increasing for the last 20 years. The aim of this paper is to present a mathematical model for the pirarucu population dynamics considering the species peculiarities, particularly the male parental care over the offspring. The solution of the dynamical systems indicates three possible equilibrium points for the population. The first corresponds to extinction; the third corresponds to a stable population close to the environmental carrying capacity. The second corresponds to an unstable equilibrium located between extinction and full use of the carrying capacity. It is shown that lack of males’ parental care closes the gap between the point corresponding to the unstable equilibrium and the point of stable non-trivial equilibrium. If guarding failure reaches a critical point the two points coincide and the population tends irreversibly to extinction. If some event tends to destabilize the population equilibrium, as for instance inadequate parental care, the model responds in such a way as to restore the trajectory towards the stable equilibrium point avoiding the route to extinction. The parameters introduced to solve the system of equations are partially derived from limited but reliable field data collected at the Mamirauá Sustainable Development Reserve (MSDR) in the Brazilian Amazonian Region.

Flood pulse and spatial dynamics of mercury in sediments in Puruzinho lake, Brazilian Amazon

The study was conducted in Puruzinho lake (Humaitá, AM) considering seasonal periods of rainy and dry in way to elucidate the flood pulse importance in the deposition, remobilization and distributions of mercury and organic matter in bottom sediments in the Madeira River Basin (Brazilian Amazon). Bottom sediments and soils samples were analyzed for total mercury and organic matter. Mercury concentrations obtained in bottom sediment were 32.20-146.40 ng g-1 and organic matter values were 3.5 - 18.0%. The main region for accumulation of mercury and organic matter was in the central and deepest lake area In the rainy season there was a greater distribution of Hg and organic matter, mainly controlled by means of income of the Madeira river water during flooding, while the predominant process in the dry season was the remobilization of total Hg due to the resuspension of bottom sediments.

The influence of the conservation status and changes in the rainfall regime on forest-savanna mosaic dynamics in Northern Brazilian Amazonia

Coupled carbon/climate models are predicting changes in Amazon carbon and water cycles for the near future, with conversion of forest into savanna-like vegetation. However, empirical data to support these models are still scarce for Amazon. Facing this scenario, we investigated whether conservation status and changes in rainfall regime have influenced the forest-savanna mosaic over 20 years, from 1986 to 2006, in a transitional area in Northern Amazonia. By applying a spectral linear mixture model to a Landsat-5-TM time series, we identified protected savanna enclaves within a strictly protected nature reserve (Maracá Ecological Station - MES) and non-protected forest islands at its outskirts and compared their areas among 1986/1994/2006. The protected savanna enclaves decreased 26% in the 20-years period at an average rate of 0.131 ha year-1, with a greater reduction rate observed during times of higher precipitation, whereas the non-protected forest islands remained stable throughout the period of study, balancing the encroachment of forests into the savanna during humid periods and savannization during reduced rainfall periods. Thus, keeping favorable climate conditions, the MES conservation status would continue to favor the forest encroachment upon savanna, while the non-protected outskirt areas would remain resilient to disturbance regimes. However, if the increases in the frequency of dry periods predicted by climate models for this region are confirmed, future changes in extension and directions of forest limits will be affected, disrupting ecological services as carbon storage and the maintenance of local biodiversity.

Transmyocardial laser revascularization. Early clinical experience

OBJECTIVE: To analyze the initial clinical experience of transmyocardial laser revascularization (TMLR) in patients with severe diffuse coronary artery disease. METHODS: Between February, 1998 and February, 1999, 20 patients were submitted to TMLR at the Heart Institute (InCor), University of São Paulo Medical School, Brazil, isolated or in association with conventional coronary artery bypass graft (CABG). All patients had severe diffuse coronary artery disease, with angina functional class III/IV (Canadian Cardiovascular Society score) unresponsive to medical therapy. Fourteen patients were submitted to TMLR as the sole therapy, whereas 6 underwent concomitant CABG. Fifty per cent of the patients had either been previously submitted to a CABG or to a percutaneous transluminal coronary angioplasty (PTCA). Mean age was 60 years, ranging from 45 to 74 years. RESULTS: All patients had three-vessel disease, with normal or mildly impaired left ventricular global function. Follow-up ranged from 1 to 13 months (mean 6.6 months), with no postoperative short or long term mortality. There was significant symptom improvement after the procedure, with 85% of the patients free of angina, and the remaining 15 % of the patients showing improvement in functional class, as well as in exercise tolerance. CONCLUSION: This novel technique can be considered a low risk alternative for a highly selected group of patients not suitable for conventional revascularization procedures.

In-stent restenosis. Acute and long-term outcomes after excimer laser coronary angioplasty

OBJETIVE: With the increased use of intracoronary stents, in-stent restenosis has become a clinically significant drawback in invasive cardiology. We retrospectively assessed the short- and long-term outcomes after excimer laser coronary angioplasty of in-stent restenosis. METHODS: Twenty-five patients with 33 incidents of in-stent restenosis treated with excimer laser coronary angioplasty (ELCA) were analyzed. Sixty-six percent were males, mean age of 73±11 years, and 83% were functional class III-IV (NYHA). ELCA was performed using 23 concentric and 10 eccentric catheters with a diameter of 1.6-2.2 mm, followed by balloon angioplasty (PTCA) and ultrasound monitoring. The procedure was performed in the following vessels: left anterior descending artery, 10; left circumflex artery, 8; right coronary artery, 6; left main coronary artery, 2; and venous bypass graft, 7. RESULTS: The ELCA was successful in 71% of the cases, and PTCA was 100% successful. The diameter of the treated vessels was 3.44±0.5mm; the minimal luminal diameter (MLD) increased from 0.30mm pre-ECLA to 1.97mm post-ELCA, and to 2.94mm post-PTCA (p<0.001). The percent stenosis was reduced from 91.4±9.5% before ECLA to 42.3±14.9% after ELCA and to 14.6 ± 9.3% after PTCA (p<0.001). Seventeen (68%) patients were asymptomatic at 6 months and 15 (60%) at 1 year. New restenosis rates were 8/33 (24.2%) at 6 months and 9 /33 (27.3%) at 12 months. CONCLUSION: ELCA is safe and effective for the treatment of in-stent restenosis. In the present sample, a slight increase in new restenotic lesions between 6 and 12 months was found.

Laser assisted extraction of pacemaker and implantable defibrillator leads

OBJECTIVE: To analyze the results of laser-assisted extraction of permanent pacemaker and defibrillator leads. METHODS: We operated upon 36 patients, whose mean age was 54.2 years, and extracted 56 leads. The reasons for extracting the leads were as follows: infection in 19 patients, elective replacement in 13, and other causes in 4 patients. The mean time of catheter placement was 7.5±5.5 years. Forty-seven leads were from pacemakers, and 9 were from defibrillators. Thirty-eight leads were in use, 14 had been abandoned in the pacemaker pocket, and 4 had been abandoned inside the venous system. RESULTS: We successfully extracted 54 catheters, obtaining a 96.4% rate of success and an 82.1% rate for complete extraction. The 2 unsuccessful cases were due to the presence of calcium in the trajectory of the lead. The mean duration of laser light application was 123.0±104.5 s, using 5,215.2±4,924.0 pulses, in a total of 24.4±24.2 cycles of application. Thirty-four leads were extracted from the myocardium with countertraction after complete progression of the laser sheath, 12 leads came loose during the progression of the laser sheath, and the remaining 10 were extracted with other maneuvers. One patient experienced cardiac tamponade after extraction of the defibrillator lead, requiring open emergency surgery. CONCLUSION: The use of the excimer laser allowed extraction of the leads with a 96% rate of success; it was not effective in 2 patients who had calcification on the lead. One patient (2.8%) had a complication that required cardiac surgery on an emergency basis.

Utilidade do Ultrassom intracardíaco no isolamento de veias pulmonares usando cateter-balão a laser

FUNDAMENTO: O isolamento das veias pulmonares (IVP) tem sido usado como endpoint para a ablação da fibrilação atrial (FA) com cateter balão. OBJETIVO: Determinar a utilidade do ultrassom intracardíaco (USIC) para guiar o IVP, usando cateter balão a laser. MÉTODOS: 59 VP foram ablacionadas em 27 cães. Imagens de Doppler foram usadas para identificar os vazamentos do fluxo sanguíneo entre a VP e o balão. Após cada liberação de energia, o cateter de mapeamento circular foi reposicionado para verificar se o isolamento tinha sido obtido. A posição de vazamento foi então correlacionada com a posição do gap no estudo patológico. A análise de regressão logística multivariada foi realizada. RESULTADOS: Cinquenta e nove VP foram submetidas à ablação. O tempo médio de energia liberada foi de 279±177 seg., o diâmetro médio do balão era de 23±3 mm, e o comprimento médio do balão era 25±4 mm. O isolamento completo foi obtido em 38/59 (64%), e foi significantemente mais comum sem vazamento: [30/38 (79%) versus 8/23 (35%), p<0,001]. Isso foi independente do tempo de aplicação (302±223 seg. vs. 266±148 sec., p=ns), potência (3,5 W/cm, 4,5 W/cm, e 5,5 W/cm), diâmetro do balão (24± 3 mm vs. 22± 3 mm, p= ns) e comprimento (27±4 mm vs. 24±4 mm, p=ns). O valor preditivo positivo para previsão de isolamento completo foi de 65% e o valor preditivo negativo foi 83%. CONCLUSÃO: Um vazamento identificável entre a VP e o dispositivo de ablação por cateter-balão observado no USIC é preditor de menor taxa de isolamento de VP mais baixas. O USIC pode ser útil para detectar vazamentos a fim de evitar o uso ineficaz de aplicação energia durante a ablação circunferencial da VP. Isto também pode ser útil quando outras energias são utilizadas.

Hemodynamic Effect of Laser Therapy in Spontaneously Hypertensive Rats

Systemic arterial hypertension (SAH) is considered to be the greatest risk factor for the development of neuro-cardiovascular pathologies, thus constituting a severe Public Health issue in the world. The Low-Level Laser Therapy (LLLT), or laser therapy, activates components of the cellular structure, therefore converting luminous energy into photochemical energy and leading to biophysical and biochemical reactions in the mitochondrial respiratory chain. The LLLT promotes cellular and tissue photobiomodulation by means of changes in metabolism, leading to molecular, cellular and systemic changes. The objective of this study was to analyze the action of low-level laser in the hemodynamic modulation of spontaneously hypertensive rats, in the long term. Animals (n = 16) were randomly divided into the Laser Group (n = 8), which received three weekly LLLT irradiations for seven weeks, and into the Sham Group (n = 8), which received three weekly simulations of laser for seven weeks, accounting for 21 applications in each group. After seven weeks, animals were cannulated by the implantation of a catheter in the left carotid artery. On the following day, the systemic arterial pressure was recorded. The Laser Group showed reduced levels of mean blood pressure, with statistically significant reduction (169 ± 4 mmHg* vs. 182 ± 4 mmHg from the Sham Group) and reduced levels of diastolic pressure (143 ± 4 mmHg* vs. 157 ± 3 mmHg from the Sham Group), revealing a 13 and 14 mmHg decrease, respectively. Besides, there was a concomitant important decline in heart rate (312 ± 14 bpm vs. 361 ± 13 bpm from the Sham Group). Therefore, laser therapy was able to produce hemodynamic changes, thus reducing pressure levels in spontaneously hypertensive rats.