Gill infection of Leporinus macrocephalus Garavello & Britski, 1988 (Osteichthyes: Anostomidae) by Henneguya leporinicola n. sp. (Myxozoa: Myxobolidae). Description, histopathology and treatment

Piau?us (Leporinus macrocephalus), were raised in 300 m2 ponds (density of 10 fish/m2) presenting asphyxia signals and daily mortality of 27 fishes. Specimens with 8-cm total body length, were collected for necropsy. Mucus of body surface and pieces of organs were collected and examined microscopically, in wet mounts, stained or in histological sections. The smears examination showed the presence of several spores in the secondary lamellae of the gill filaments, identified as Henneguya leporinicola n.sp (Myxozoa: Myxobolidae). Histopathological study showed epithelial hyperplasia and fulfilling of the spaces between the secondary lamellae, congestion and telangiectasia sinusoidal. It was also observed hyperplasia of the goblet cells and several cysts of parasite with 70.3 microns diameter. Such cysts were situated among the secondary lamellae, covered or not by the hyperplasic epithelium. With this diagnostic, three applications of formalin solution 10 ml/m3 were carried out. Fifteen days after that, fish were examined again to ascertain whether the treatment was efficient on disease caused by the protozoa. The tissue alterations present in the gills after the treatment were just a moderate sinusoidal congestion and a slight epithelial hyperplasia on the base of the secondary lamellae.     

The duty to recontact: attitudes of genetics service providers

The term "duty to recontact" refers to the possible ethical and/or legal obligation of genetics service providers (GSPs) to recontact former patients about advances in research that might be relevant to them. Although currently this practice is not part of standard care, some argue that such an obligation may be established in the future. Little information is available, however, on the implications of this requirement, from the point of view of GSPs. To explore the opinions of genetics professionals on this issue, we sent a self-administered questionnaire to 1,000 randomly selected U.S. and Canadian members of the American Society of Human Genetics. We received 252 completed questionnaires. The major categories of respondents were physician geneticist (41%), Ph.D. geneticist (30%), and genetic counselor (18%); 72% of the total stated that they see patients. Respondents indicated that responsibility for staying in contact should be shared between health professionals and patients. Respondents were divided about whether recontacting patients should be the standard of care: 46% answered yes, 43% answered no, and 11% did not know. Those answering yes included 44% of physician geneticists, 53% of Ph.D. geneticists, and 31% of genetic counselors; answers were statistically independent of position or country of practice but were dependent on whether the respondent sees patients (43% answered yes) or not (54% answered yes). There also was a lack of consensus about the possible benefits and burdens of recontacting patients and about various alternative methods of informing patients about research advances. Analysis of qualitative data suggested that most respondents consider recontacting patients an ethically desirable, but not feasible, goal. Points to consider in the future development of guidelines for practice are presented.     

Role of Anopheles (Kerteszia) bellator as malaria vector in southeastern Brazil (Diptera: Culicidae)

New research concerning Anopheles bellator in the southeast of the State of S?o Paulo, Brazil, are reported. Adult females of this mosquito showed remarkable endophily and endophagy which was even greater than An. cruzii. The epidemiological role of this anopheline as a malaria vector is discussed.     

Hemolytic activity and siderophore production in different Aeromonas species isolated from fish

The hemolytic activity and siderophore production of several strains of motile aeromonads were determined. The hemolytic activity of Aeromonas caviae and Aeromonas eucrenophila was enhanced after trypsinization of the samples. The enhancement of hemolysis was observed in strains that carried an aerolysin-like gene, detected by a PCR procedure. Siderophore production was demonstrated in all but one strain of Aeromonas jandaei. No apparent relationship was observed between the presence of plasmid DNA and hemolysis or siderophore production.     

Estimating the number of clusters in multivariate data by self-organizing maps

Determining the structure of data without prior knowledge of the number of clusters or any information about their composition is a problem of interest in many fields, such as image analysis, astrophysics, biology, etc. Partitioning a set of n patterns in a p-dimensional feature space must be done such that those in a given cluster are more similar to each other than the rest. As there are approximately Kn/K! possible ways of partitioning the patterns among K clusters, finding the best solution is very hard when n is large. The search space is increased when we have no a priori number of partitions. Although the self-organizing feature map (SOM) can be used to visualize clusters, the automation of knowledge discovery by SOM is a difficult task. This paper proposes region-based image processing methods to post-processing the U-matrix obtained after the unsupervised learning performed by SOM. Mathematical morphology is applied to identify regions of neurons that are similar. The number of regions and their labels are automatically found and they are related to the number of clusters in a multivariate data set. New data can be classified by labeling it according to the best match neuron. Simulations using data sets drawn from finite mixtures of p-variate normal densities are presented as well as related advantages and drawbacks of the method.