[Utility of SPECT/CT scan for anatomical localization of pararectal and presacral sentinel nodes in prostate cancer]. / Utilidad de la SPECT-TC para la localización anatómica de los ganglios centinelas presacrales y pararrectales en el cáncer de próstata.

AIM: This study has aimed to evaluate the added value of SPECT-CT scan in the preoperative assessment of sentinel nodes of the presacral and pararectal regions localized outside the standard area of extended pelvic lymphadenectomy for the staging of the pelvis in prostate cancer. SPECT-CT scan can serve as a guide for the excision of these nodes by lymphadenectomy by open surgery or laparoscopy. MATERIAL AND METHODS: We evaluated 4 patients with prostate cancer presenting sentinel nodes in the pararectal and presacral regions on SPECT-CT scan performed in addition to lymphoscintigraphy. These patients underwent lymphadenectomy with robot-assisted laparoscopy together with prostatectomy. All of the excised lymph nodes were sent for histopathology study. RESULTS: An average of 6 sentinel nodes per patient were found on SPECT-CT scan with a mean of 2 sentinel nodes in presacral/pararectal región. Lymphadenectomy including these areas was performed. Pararectal/presacral sentinel nodes of all patients depicted by SPECT-CT scan were tumor free on histopathology study. Sentinel nodes (no pararectal/presacral) were positive for malignancy in only one patient. CONCLUSION: Preoperative SPECT-CT scan is a useful tool to localize the sentinel nodes in pararectal/presacral regions. It can be an anatomic guide for new modalities of laparoscopic surgery such as robot-assisted procedures that can access the pelvic areas visualized with SPECT-CT scan, making excision of these nodes possible.

Soil microbial populations, community composition, and activity as affected by repeated applications of hog and cattle manure in eastern Saskatchewan.

A field site near Humboldt, Saskatchewan, was annually treated with hog or cattle manure and cropped to canola, spring wheat, barley, and canola from 1997 to 2000. During each growing season, soil was analyzed for microbial populations in terms of activity and community structure, and crops were assessed for root rot and foliar diseases. Microbial activity in soils treated with cattle manure was higher than in soils treated with hog manure or urea. Similarly, nitrous oxide emissions from soil increased with increasing rates of hog and cattle manure. Potential human pathogens, including Rahnella, Serratia, Proteus, Leclercia, and Salmonella species, were identified in soils that received cattle manure, whereas pseudomonads were the dominant species in the hog-manure-treated soil. Fecal coliforms were confirmed in soils that received hog or cattle manure. However, Enterobacteriaceae populations were 10-fold higher in soils receiving cattle manure than in soils receiving the other treatments. Increasing cattle manure rates increased fecal coliform population, but there was no indication that increased hog manure rates increased fecal coliform populations. Addition of urea, hog manure, or cattle manure to the soil did not increase foliar disease in wheat, barley, and canola and had variable effects on root rot incidence in cereals.

On two methods to estimate production of Eichhornia crassipes in the eutrophic Pampulha reservoir (MG, Brazil).

This paper deals with variations in biomass and in the production of Eichhornia crassipes (water hyacinth) in a eutrophic tropical reservoir. Net production was assessed by both a traditional method and a demographic approach. The initial biomass ranges from 96 g DW.m-2 to a maximum of 2027 g DW.m-2. Net production estimates varied greatly according to which method was used to calculate them (traditional: 20.6 ton DW.hectare-1.year-1, demographic: 226.9 ton DW.year-1).

Current advances on the study of snail-snail interactions, with special emphasis on competition process.

Field work research on population dynamic of snails from the regions of Belo Horizonte and Lagoa Santa give much information about interactions among two or more species of mollusks: Pomacea haustrum, Biomphalaria glabrata, B. tenagophila, B. straminea and Melanoides tuberculata. Data ranging from two years to several decades ago suggest that the Pampulha reservoir is like a cemetery of B. glabrata and B. straminea, species that coexist for more than 14 years in a small part of a stream, whereas only B. glabrata lives in all the streams of the basin. In the last ten to twenty years B. tenagophila has coexisted with P. haustrum and M. tuberculata in the Serra Verde ponds and in the Pampulha dam. However these species have not settled in any of the brooks, except temporarily. The data suggest that the kind of biotope and the habitat conditions are decisive factors for the permanence of each species in its preferencial biotope. B. glabrata, natural from streams and riverheads, quickly disappears from the reservoirs and ponds where it coexists with other species for a short time, independently of the competitive process. Competition needs to be better studied, since in Central America and Caribean islands this kind of study has favored the biological control of planorbid species.

Degree of host-parasite compatibility between Schistosoma mansoni and their intermediate molluscan hosts in Brazil.

The compatibility of Biomphalaria tenagophila, B. straminea and B. glabrata from Minas Gerais with different strains of Schistosoma mansoni was evaluated using the method of Frandsen (1979b) in standardized experiments. One hundred and fifty of each species of snail were individually exposed in the laboratory to 50 miracidia of S. mansoni lines LE, SJ and AL. The cercariae from the infected snails were counted and used to calculate TCP/100 indices, which were compared with those of Frandsen (1979b). For B. tenagophila the TCP/100 indices varied from 37,996 to 74,266 (class II and III). The snail was poorly compatible with LE (class II) and compatible with SJ and AL (class III). For B. straminea the indices varied from 9,484 to 20,508. The snail was not very compatible with SJ (class I) and poorly compatible with LE and AL (class II). For B. glabrata the indices varied from 588,828 to 1,039,065. The snails was extremely compatible (class VI) with the three lines of S. mansoni. These results confirm the epidemiological importance of B. glabrata in Brazil followed by B. tenagophila and B. straminea.

[Competitive behavior of Biomphalaria glabrata and Biomphalaria tenagophila--laboratory studies]. / Estratégia competitiva entre Biomphalaria glabrata e Biomphalaria tenagophila--estudos de laboratório.

Observation about cohabitation among B. glabrata and B. tenagophila revealed a greater vulnerability of B. tenagophila population during the process of competition when its density was severely decreased in 12 trials, moderate in 2 trials. It was higher than B. glabrata in only one trial. Some snail water chemical parameters analysed such as pH, alkalinity, conductivity and oxygen dissolved, and the viability rate of batch of eggs didn't give subsidy to explain the competition mechanism. The newly-born survival, in the situation of cohabitation, was low for both species. This reveals the existence of intra and interspecific competitive interaction. The fertility rate reduction of B. tenagophila during the cohabitation was considered as a cause of its exclusion. One of the factors that seems to have influenced the fertility rate was a possible wrong crossing.

[Potential of Biomphalaria tenagophila from Pampulha lake, Belo Horizonte, MG, as a host of Schistosoma mansoni]. / Potencialidade de Biomphalaria tenagophila do lago da Pampulha, Belo Horizonte, MG, como hospedeira do Schistosoma mansoni.

Biomphalaria tenagophila snails, from a population originally obtained from "Pampulha" lake, Belo Horizonte, Minas Gerais State, Brazil, were exposed to miracidia from four strains of Schistosoma mansoni: "LE" and "HK" from Belo Horizonte, "AL" from Alagoas and "SJ" from São José dos Campos, São Paulo. The "LE", "AL" and "SJ" strains are maintained in the laboratory and the "HK" strain was obtained from feces of a patient residing near to "Pampulha" lake. Infection rates were of 4% ("LE" strain), 6% ("HK" strain), 30% ("SJ" strain) and 40% ("AL" strain). These infection rates were similar to those obtained by others authors for B. tenagophila from Minas Gerais. Experimentally infected snails when compared to B. glabrata of the control group and B. tenagophila naturally infected in "Pampulha" lake shed similar number of cercariae (2000 cercariae/snail). The high density of B. tenagophila in the "Pampulha" lake, the number of cercariae shed by naturally infected snails, the great number of persons who use the water for fishing and swimming, and the water contamination with human feces, are favourable factors for growing the Schistosomiasis focus in the lake.

[Physical and chemical characteristics of the habitat of Biomphalaria tenagophila (Mollusca, Planorbidae)]. / Características físicas e químicas do habitat da Biomphalaria tenagophila (Mollusca, Planorbidae).

Samples of water and snails collected through aleatory scoops in a small dam were done to obtain data concerning the physical and chemical characteristics of the water and their possible influence on biological aspects of the life cycle of snails. Among the 17 analysed parameters, Alkalinity and Conductivity showed a positive correlation with the density of B. tenagophila (r = +0.224 and r = +0.290), while CO2 and Acidity were negatively correlated with this populacional parameter (r = -0.592 and 0.601). Alkalinity and Total Hardness values were slightly higher than 100 mg/l CaCO3. Chlorides and Conductivity showed means of 94.9 +/- 38.7 and 680.1 +/- 643 microS/cm; these values are very high for that region. Other factors like pH and OD are according to the pattern for provision untreated waters. The density of B. tenagophila declined in the 6th month after a long period of torrential rains and in the rainy summers. In the colder months of the following year the density was higher (until 124 individuals/months/90 scoops). The monthly mean of the diameters of the snails was always larger than 13 mm, reaching 21.4 +/- 4.1 mm, but the mode was about 17 mm. There was no correlation between diameter/density (r = 0.037) and density/temperature (r = 0.065).