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.

The population structure of Trypanosoma cruzi: expanded analysis of 54 strains using eight polymorphic CA-repeat microsatellites

Recently we cloned and sequenced the first eight Trypanosoma cruzi polymorphic microsatellite loci and studied 31 clones and strains to obtain valuable information about the population structure of the parasite. We have now studied 23 further strains, increasing from 11 to 31 the number of strains obtained from patients with chronic Chagas disease. This expanded set of 54 strains and clones analyzed with the eight microsatellites markers confirmed the previously observed diploidy, clonal population organization and very high polymorphism of T. cruzi. Moreover, this new study disclosed two new features of the population genetic structure of T. cruzi. The first was the discovery that, similarly to what we had previously shown for strains isolated from insect vectors, mammals and humans with acute disease, isolates from patients in the chronic phase of Chagas disease could also be multiclonal, albeit at a reduced proportion. Second, when we used parsimony to display the genetic relationship among the clonal lineages in an unrooted Wagner network we observed, like before, a good correlation of the tree topography with the classification in three clusters on the basis of single locus analysis of the ribosomal RNA genes. However, a significant new finding was that now the strains belonging to cluster 2 split in two distant sub-clusters. This observation suggests that the evolutionary history of T. cruzi may be more complex than we previously thought.

Attaining the minimum target of resolution WHA 54.19 for schistosomiasis control in the Rainforest Zone of the state of Pernambuco, Northeastern Brazil

Resolution 19 of the 54th World Health Assembly (WHA-54.19) urged member nations to promote preventive measures, ensure treatment and mobilize resources for control of schistosomiasis and soil-transmitted helminthiases (STH). The minimum target is to attend 75% of all school-age children at risk by year 2010. The Brazilian Ministry of Health (MoH) recommends biennial surveys of whole communities and treatment of the positives through the Schistosomiasis Control Program within the Unified Health System (PCE-SUS). However, by 2004 the PCE-SUS had covered only 8.4% of the 1.2 million residents in the Rainforest Zone of Pernambuco (ZMP). Six of the 43 municipalities still remained unattended. Only three of the municipalities already surveyed reached coverage of 25% or more. At least 154 thousand children in the 7-14 years old range have to be examined (and treated if positive) within the next five years to attend the minimum target of the WHA 54.19 for the ZMP. To make this target feasible, it is suggested that from 2006 to 2010 the PCE-SUS actions should be complemented with school-based diagnosis and treatment, involving health and educational organs as well as community associations to include both children in schools and non-enrolled school-age children.

Treatment of an Aedes aegypti colony with the Cry11Aa toxin for 54 generations results in the development of resistance

To study the potential for the emergence of resistance in Aedes aegypti populations, a wild colony was subjected to selective pressure with Cry11Aa, one of four endotoxins that compose the Bacillus thuringiensis serovar israelensis toxin. This bacterium is the base component of the most important biopesticide used in the control of mosquitoes worldwide. After 54 generations of selection, significant resistance levels were observed. At the beginning of the selection experiment, the half lethal concentration was 26.3 ng/mL and had risen to 345.6 ng/mL by generation 54. The highest rate of resistance, 13.1, was detected in the 54th generation. Because digestive proteases play a key role in the processing and activation of B. thuringiensis toxin, we analysed the involvement of insect gut proteases in resistance to the Cry11Aa B. thuringiensis serovar israelensis toxin. The protease activity from larval gut extracts from the Cry11Aa resistant population was lower than that of the B. thuringiensisserovar israelensis susceptible colony. We suggest that differences in protoxin proteolysis could contribute to the resistance of this Ae. aegypti colony.

ESTUDO DA CARCAÇA DE MACHOS BRAFORD DESMAMADOS AOS 72 OU 210 DIAS, ABATIDOS AOS CATORZE MESES

O objetivo deste trabalho foi comparar as características de carcaça de machos desmamados em duas idades, aos 72 (T72) e aos 210 (T210) dias. Utilizaram-se 36 terneiros 5/8 Hereford e 3/8 Nelore, não castrados, os quais foram terminados em confinamento e abatidos aos 14 meses de idade. Não houve diferença significativa quanto ao peso de fazenda (T72=424 kg e T210=406 kg), rendimento de carcaça quente (T72=54,7% e T210=54,4%), peso de carcaça quente (T72=232 kg e T210=221 kg) e fria (T72=224 kg e T210=214 kg) entre os dois grupos. Os animais desmamados aos 72 dias apresentaram carcaça com conformação ligeiramente superior (11,8 pontos vs. 11,3 pontos) e maior percentagem de costilhar em relação aos novilhos desmamados aos 210 dias, cujos cortes dianteiro e traseiro não diferiram significativamente. Não houve diferença significativa entre as variáveis comprimento de carcaça, comprimento de perna, comprimento de braço, perímetro de braço e espessura de coxão. A espessura de gordura de cobertura não diferiu significativamente entre os dois grupos de carcaça, sendo 4,6 mm e 4,2 mm, respectivamente para T72 e T210 dias. Os resultados mostraram que animais desmamados aos 72 dias de idade apresentam carcaça comparável aos desmamados com 210 dias, com peso e acabamento dentro dos limites exigidos pelos frigoríficos.

Análise florística e estrutural de sistemas silviagrícolas em Tomé-Açu, Pará

O objetivo deste trabalho foi analisar a composição florística e estrutural de sistemas silviagrícolas em Tomé-Açu, Pará. Os dados dendrométricos foram obtidos por inventário em 40 parcelas amostrais, com três unidades cada uma, no total de 120 unidades de 10x10 m. Foi inventariada a média de 1.424,3 indivíduos por hectare, pertencentes a 27 famílias e a 54 espécies. Tendo-se considerado a variabilidade dos estágios vegetativos, os diferentes sistemas silviagrícolas (SAF) foram divididos em quatro classes hierárquicas: SAF 1, SAF 2, SAF 3, e SAF 4, para estabelecer um sistema de classificação passível de ser utilizado em outras avaliações de campo e em classificações digitais por meio do sensoriamento remoto. Espécies observadas em outros sistemas da região amazônica também foram relevantes para este estudo, especialmente Theobroma cacao, T. grandiflorum e Euterpe oleracea que, juntas, apresentaram médias de frequência relativa de 51%, densidade relativa de 69,2%, dominância relativa de 50,1% e índice de valor de importância de 56,8%. Os dados médios de diversidade florística, abundância, área basal e valor de importância indicam os sistemas silviagrícolas da região de Tomé-Açu como sistemas de produção com potencial econômico e ambiental, se adotado manejo adequado e racional.