Seroepidemiological survey of human toxoplasmosis in Osorno, Region X, Chile, 1998]

A serological survey was carried out in Osorno X Region, Chile (40 degrees 21'-40 degrees 46' South lat, and 73 degrees 26' -72 degrees-46' West long.). An indirect hemagglutination test (IHAT) for toxoplasmosis was performed to 305 persons--160 blood donors and 145 with sexually transmitted disease (STD). The age of the surveyed persons (167 males and 138 females) varied between 10 and 72 years. IHAT titers > 16 were considered as positive. The general prevalence was 20.3%--21.2% in blood donors and 19.3% in persons with some STD--with no differences between males and females. However, significant differences between males and females with STD were found (35.6% and 8.1% respectively). No differences between urban and rural inhabitants were found with a slight higher prevalence in the urban ones. No antibodies against Toxoplasma gondii were detected in six AIDS patients. The importance of performing toxoplasmosis immunodiagnosis and individual prophylaxis to avoid the infection in high risk group are recommended.     

Adipose tissue-derived factors as potential biomarkers in cachectic cancer patients

Cachexia, a paraneoplastic syndrome markedly associated with worsened prognosis in cancer patients, provokes profound wasting of both lean and adipose mass in an association with a state of metabolic “chaos”. The white adipose tissue responds to cachexia with marked local inflammation and may be thus a relevant contributor to systemic inflammation. To address this hypothesis we examined the correlation between tissue expression of adipokines and plasma concentration in cachectic and stable weight patients with or without cancer. Adiponectin and liver-derived CRP concentration were significantly higher in the cachectic groups when compared with stable weight patients (P < 0.01). The concentration of plasma IL-6 was higher (11.4-fold) in the cancer cachectic group when compared with weight-stable controls, and presented a significant correlation with the presence of cancer (P < 0.001). A marked increase (5-fold) in IL-6 as a result of the interaction between the presence of cachexia and the presence of tumour was observed in the subcutaneous tissue of the patients, yet not in the visceral depot. Plasma adiponectin levels were higher in cachectic cancer patients, compared with stable weight cancer patients individually matched by age, sex, and BMI, and the subcutaneous depot was found to be the main contributing tissue, rather than the visceral pad. Based on the results we concluded that the subcutaneous adipose tissue is associated with plasma changes that may function as markers of cachexia.     

Urban noise influences vocalization structure in the House Wren Troglodytes aedon

Urban habitats are noisy and constrain acoustic communication in birds. We analysed the effect of anthropogenic noise on the vocalization characteristics of House Wrens Troglodytes aedon at two sites with different noise levels (rural and urban). We measured in each song and song trill the frequency bandwidth, maximum amplitude, highest and minimum frequency, and trill rate. In noisy urban environments, there was a reduction in bandwidth and an increase in trill rate relative to quieter, rural environments. The whole song of birds from both populations increased in minimum frequency as noise increased, improving song transmission.     

Conceptual and statistical problems with the use of the Shannon-Weiner entropy index in bioacoustic analyses

Information theory and its indices were developed for human communication to predict the amount of information transferred in a message. One such index, the Shannon-Weiner index (SWI), has often been used to analyse information from other fields in which its application may not be appropriate. In ecoacoustics, SWI is used to compare acoustic diversity (i.e. a measure derived by integrating the richness and abundance of animal sounds) between locations. In animal communication, SWI is used to quantify repertoire complexity (i.e. a measure derived by integrating the number and abundance of sound types produced by individuals or species) as an approach to understanding signal evolution. We discuss problems associated with using the SWI in ecoacoustics and animal communication. Specifically, we discuss conceptual and statistical problems associated with the SWI and then illustrate these problems using hypothetical data. In ecoacoustics, the SWI’s assumptions of random variables and independent samples are often violated. In animal communication, the SWI fails to distinguish among repertoires in which the number of sound types and the abundance of each sound type differ. We also show that other methods do capture these differences. We conclude that the SWI does not adequately represent acoustic diversity or repertoire complexity due to the multiple conceptual and statistical issues associated with its use. We recommend other analytical methods to more fully describe these biological systems, including goodness of fit, Morisita similarity index and Markov chain analysis. These methods provide more information for future comparisons and permit researchers to test hypotheses more directly.     

Molecular phylogenetics of sexual and parthenogenetic Timema walking-sticks

We inferred a phylogeny for the walking-stick genus Timema (Insecta: Phasmatoptera) using mitochondrial DNA sequence, and we used the phylogeny to infer temporal patterns of speciation and the evolutionary history of parthenogenesis. Maximum parsimony, neighbour-joining and maximum-likelihood analyses of 660 base pairs (bp) of cytochrome oxidase I (COI) yielded phylogenies that were well resolved and topologically identical or very similar. Application of an insect molecular clock for COI suggests that the genus originated in southern California, northern Mexico or Arizona about 20 million years ago and underwent a burst of speciation 1.5 to 3 million years ago during the uplifts of the Sierra Nevada, Coast, and Transverse Ranges. The phylogeny indicates that the three parthenogenetic lineages of Timema have arisen independently and are each closely related to morphologically indistinguishable or similar sexual species. Each of the three lineages exhibits an allopatric or parapatric, and more northerly, distribution with regard to their closest sexual relative. COI divergence levels between each of the three parthenogens and their closest sexual relative suggest ancient origins of parthenogenesis, 1.5 to 3 million years ago, that may coincide with the extensive glaciation that formed the North American ice sheets.     

Usefulness of the ELISA-IgG test in sera and filter paper blood eluates in the Chagas disease immunodiagnosis]

An ELISA-IgG test using a soluble extract of Trypanosoma cruzi antigen has been developed. One hundred and seventy eight sera (74 healthy people, 44 chagasic patients with positive xenodiagnosis and 60 with clinical symptoms), and 64 paper filter blood eluates (35 healthy people, 10 chagasic patients and 19 with clinical symptoms) were tested by ELISA-IgG and an indirect hemagglutination test. Both types of methods presented an overall average concordance of 98.3% and 100.0% with sera and filter paper blood eluates respectively. A cut off (average of optical density plus 3 standard deviations) of 0.365 and 0.379 for sera and eluates was found. The use of ELISA-IgG in Chagas' disease clinical diagnosis and seroepidemiological studies is discussed.     

To What did They Consent? Understanding Consent Among Low Literacy Participants in a Microbicide Feasibility Study in Mazabuka,Zambia

We conducted a study to review the consenting process in a vaginal Microbicide feasibility study conducted in Mazabuka, Zambia. Participants were drawn from those participating in the microbicide study. A questionnaire and focus group discussion were used to collect information on participants understanding of study aims, risks and benefits. Altogether, 200 participants took part in this study. The results of the study showed that while all participants signed or endorsed their thumbprints to the consent forms, full informed consent was not attained from most of the participants since 77% (n = 154) of the participants had numerous questions about the study and 34% (n = 68) did not know who to get in touch with concerning the study. Study objectives were not fully understood by over 61% of the participants. Sixty four percent of the participants were not sure of the risks of taking part in the microbicide study. A significant number thought the study was all about determining their HIV status. Some participants were concerned that their partners were not on the trial as they were convinced that being on the study meant that that they had a lifetime protection from HIV infection. The process of obtaining consent was inadequate as various phases of the study were not fully understood. We recommend the need for researchers to reinforce the consenting process in all studies and more so when studies are conducted in low literacy populations.