A miRNA signature suggestive of nodal metastases from laryngeal carcinoma.

The discovery that miRNAs are frequently deregulated in tumours offers the opportunity to identify them as prognostic and diagnostic markers. The aim of this multicentric study is to identify a miRNA expression profile specific for laryngeal cancer. The secondary endpoint was to identify specific deregulated miRNAs with potential as prognostic biomarkers for tumour spread and nodal involvement, and specifically to search for a miRNA pattern pathognomonic for N+ laryngeal cancer and for N- tissues. We identified 20 miRNAs specific for laryngeal cancer and a tissue-specific miRNA signature that is predictive of lymph node metastases in laryngeal carcinoma characterised by 11 miRNAs, seven of which are overexpressed (upregulated) and four downregulated. These results allow the identification of a group of potential specific tumour biomarkers for laryngeal carcinoma that can be used to improve its diagnosis, particularly in early stages, as well as its prognosis.

Trypanosoma cruzi genotyping supports a common source of infection in a school-related oral outbreak of acute Chagas disease in Venezuela.

Trypanosoma cruzi I, a discrete typing unit (DTU) found in human infections in Venezuela and other countries of the northern region of South America and in Central America, has been recently classified into five intra-DTU genotypes (Ia, Ib, Ic, Id, Ie) based on sequence polymorphisms found in the spliced leader intergenic region. In this paper we report the genotype identification of T. cruzi human isolates from one outbreak of acute orally acquired Chagas disease that occurred in a non-endemic region of Venezuela and from T. cruzi triatomine and rat isolates captured at a guava juice preparation site which was identified as the presumptive source of infection. The genotyping of all these isolates as TcId supports the view of a common source of infection in this oral Chagas disease outbreak through the ingestion of guava juice. Implications for clinical manifestations and dynamics of transmission cycles are discussed.

[Methodological aspects in the evaluation of turn-over and up/down sizing as indicators of work-related stress]. / Aspetti metodologici per la valutazione di turn-over e up/down-sizing quali indicatori di stress da lavoro.

We discuss the methodological aspects related to the evaluation of turn-over and up-down sizing as indicators of work-related stress, in complex organizations like a university hospital. To estimate the active workers population we developed an algorithm which integrated several administrative databases. The indicators were standardized to take into account some potential confounders (age, sex, work seniority) when considering different hospital structures and job mansions. Main advantages of our method include flexibility in the choice of the analysis detail (hospital units, job mansions, a combination of both) and the possibility to describe over-time trends to measure the success of preventive strategies.

Panstrongylus rufotuberculatus (Champion, 1899) naturalmente infectados con Trypanosoma cruzi en el estado Miranda, Venezuela / Panstrongylus rufotuberculatus (Champion, 1899) naturally infected with Trypanosoma cruzi in Miranda state, Venezuela

Dos ejemplares de Panstrongylus rufotuberculatus fueron capturados en una vivienda de El Hatillo, estado Miranda. En ambos se confirma la presencia de Trypanosoma cruzi. Se estudian algunos parámetros biológicos para estimar el comportamiento de uno de los aislados (Pr), encontrándose que tanto el cultivo en medios acelulares como la inoculación en ratones fueron exitosos. Así mismo, 73,3% de los Rhodnius de laboratorio se infectaron y 30,6% de los parásitos presentaron metaciclogénesis, mientras que in vitro se obtuvo 25,5%. La identificación molecular correspondió a T. cruzi. Este hallazgo es importante debido a la posible emergencia de esta especie silvestre que por alteración antrópica de sus hábitats naturales puede estar en proceso de dispersión, penetración y domiciliación de las viviendas, implicando la posibilidad de transmisión del parásito al ser humano y animales domésticos.

Two specimens of Panstrongylus rufotuberculatus were captured in a house in El Hatillo, Estado Miranda. In both specimens the presence of Trypanosoma cruzi was confirmed. We studied some biological parameters for estimating the behavior of the isolates, finding in both that cell-free culture media as inoculation in mice were successful. Also, 73.3% of Rhodnius prolixus fed on infected mice became infected and 30.6% of the parasites developed to metacyclic forms whereas in vitro only 25.5% was obtained. Furthermore, the molecular identification corresponded to T. cruzi. This finding is important due to the possible emergence of wild species by anthropogenic alteration of their natural habitats, and this may become a process of dispersion, penetration and clearance of houses, implying the possibility of transmitting the parasite to humans and pets.

Stridulatory sound emission of Panstrongylus rufotuberculatus Champion, 1899, (Hemiptera: Reduviidae: Triatominae).

This study contains the first report of stridulatory sound observed in Panstrongylus rufotuberculatus Champion, 1899, and also a new record of this species in Venezuela. The conditions in which stridulation occurred are described, as well as the general environmental characteristics of the localities where it was found. This triatomine only performs the sound in conditions of extreme provocation.

Stridulatory sound emission of Panstrongylus rufotuberculatus Champion, 1899, (Hemiptera: Reduviidae: Triatominae)

Este estudo contém o primeiro reporte da estridulação observada em Panstrongylus rufotuberculatus Champion, 1899, e um novo registro desta espécie na Venezuela. Descrevem-se as condições em que ocorre a estridulação, como também as características gerais das localidades onde foi capturado. Este triatomino só emite som em condições de extrema provocação.

Stridulatory sound emission of Panstrongylus rufotuberculatus Champion, 1899, (Hemiptera: Reduviidae: Triatominae)

This study contains the first report of stridulatory sound observed in Panstrongylus rufotuberculatus Champion, 1899, and also a new record of this species in Venezuela. The conditions in which stridulation occurred are described, as well as the general environmental characteristics of the localities where it was found. This triatomine only performs the sound in conditions of extreme provocation.

Este estudo contém o primeiro reporte da estridulação observada em Panstrongylus rufotuberculatus Champion, 1899, e um novo registro desta espécie na Venezuela. Descrevem-se as condições em que ocorre a estridulação, como também as características gerais das localidades onde foi capturado. Este triatomino só emite som em condições de extrema provocação.

Pest management strategies in traditional agriculture: an African perspective.

African agriculture is largely traditional--characterized by a large number of smallholdings of no more than one ha per household. Crop production takes place under extremely variable agro-ecological conditions, with annual rainfall ranging from 250 to 750 mm in the Sahel in the northwest and in the semi-arid east and south, to 1500 to 4000 mm in the forest zones in the central west. Farmers often select well-adapted, stable crop varieties, and cropping systems are such that two or more crops are grown in the same field at the same time. These diverse traditional systems enhance natural enemy abundance and generally keep pest numbers at low levels. Pest management practice in traditional agriculture is a built-in process in the overall crop production system rather than a separate well-defined activity. Increased population pressure and the resulting demand for increased crop production in Africa have necessitated agricultural expansion with the concomitant decline in the overall biodiversity. Increases in plant material movement in turn facilitated the accidental introduction of foreign pests. At present about two dozen arthropod pests, both introduced and native, are recognized as one of the major constraints to agricultural production and productivity in Africa. Although yield losses of 0% to 100% have been observed on-station, the economic significance of the majority of pests under farmers' production conditions is not adequately understood. Economic and social constraints have kept pesticide use in Africa the lowest among all the world regions. The bulk of pesticides are applied mostly against pests of commercial crops such as cotton, vegetables, coffee, and cocoa, and to some extent for combating outbreaks of migratory pests such as the locusts. The majority of African farmers still rely on indigenous pest management approaches to manage pest problems, although many government extension programs encourage the use of pesticides. The current pest management research activities carried out by national or international agricultural research programs in Africa focus on classical biological control and host plant resistance breeding. With the exception of classical biological control of the cassava mealybug, research results have not been widely adopted. This could be due to African farmers facing heterogeneous conditions, not needing fixed prescriptions or one ideal variety but a number of options and genotypes to choose from. Indigenous pest management knowledge is site-specific and should be the basis for developing integrated pest management (IPM) techniques. Farmers often lack the biological and ecological information necessary to develop better pest management through experimentation. Formal research should be instrumental in providing the input necessary to facilitate participatory technology development such as that done by Farmer Field Schools, an approach now emerging in different parts of Africa.

Trypanosoma cruzi and human ubiquitin are immunologically distinct proteins despite only three amino acid difference in their primary sequence.

The high similarity between Trypanosoma cruzi and human ubiquitin prompted us to characterize the human humoral immunity to host and parasite ubiquitin in Chagas disease and its possible role in Chagas autoimmunity. We have used a simplified one step purification procedure to partially purify T. cruzi ubiquitin. Using this preparation we have performed ELISA and Western blots, to show that chagasic sera recognise T. cruzi but not human or Leishmania ubiquitin indicating a species-specific response. Our results show that despite the high degree of similarity in the primary structure of human and T. cruzi ubiquitins, the three amino acid difference is sufficient to distinguish parasite versus host proteins.

Insect pests of beans in Africa: their ecology and management.

Damage by insect pests, inter alia, is considered the limiting factor of bean production in Africa. This paper reviews the current status of insect pests of beans, focusing on their ecology and management, as well as the potential for integrated pest management (IPM) approaches in subsistence farming conditions, under which most beans are grown in Africa. Although numerous insect pests attack all parts of beans, bean stem maggots and bruchids are the most important field and storage pests, respectively. Foliage beetles, flower thrips, pollen beetles, pod borers, pod bugs, and sap suckers such as aphids also inflict significant damage. Control of bean pests in Africa is achieved through the use of a traditional IPM approach that consists of appropriate sowing dates, optimum plant density, varietal mixtures, intercropping, good crop husbandry, and locally available materials. Research should focus on low-input IPM approaches that encompass farmers' current practices, host-plant resistance, and natural biological control.

Isolation and identification of house fly,Musca domestica L., repellents from pepper tree,Schinus molle L.

Foliage from the pepper tree,Schinus molle L., is traditionally used in Ethiopia to "repel" house flies,Musca domestica L. The volatile extracts of pepper tree leaves were shown to have repellent and feeding-deterrent activity against house flies in a two-choice laboratory bioassay. High-performance liquid chromatographic fractionation of steam-distilled volatiles from leaves, monitored by laboratory bioassays, demonstrated that bioactivity is associated with two compounds,cis-menth-2-en-1-ol andtrans-piperitol. The absolute configuration of the latter was established as (1S,6S)-piperitol by comparison of acetyl lactate derivatives. Racemic compounds were synthesized from piperitone, and bioassays with house flies indicatedtrans-piperitol to be the most active house fly repellent.

Cloning and partial characterization of a 28 kDa antigenic protein of Trypanosoma cruzi.

Eleven antigenic clones were isolated from a Trypanosoma cruzi cDNA expression library using a pool of Chagasic sera from Venezuelan patients. These clones were tested with 26 Chagasic sera and 11 sera from patients with other diseases. One clone (Clone 2) reacted with the majority of the Chagasic sera and did not react with the non-Chagasic sera. Restriction enzyme digestion of Clone 2 DNA showed that it contained an insert of 5.2 kb. In a Southern blot of a pulse field gel electrophoresis, Clone 2 hybridized to three T. cruzi chromosomal fragments. By Northern blot analyses, it was observed that the clone hybridizes to a major T. cruzi RNA band of 0.97 kb and to two minor bands of 4.8 and 6.3 kb. The expression of these three RNAs was higher in trypomastigotes than in epimastigotes or spheromastigotes. Specific antibodies isolated against the beta-galactosidase-Clone 2 fusion protein expressed in E. coli reacted with a 28 kilodalton protein in T. cruzi.

Cyclic AMP in the Malpighian tubule fluid and in the urine of Rhodnius prolixus.

We demonstrate the presence of cyclic adenosine monophosphate (cAMP) in the fluid secreted by isolated Malpighian tubules of Rhodnius prolixus. In addition, we show that fifth-instar R. prolixus excrete cAMP in the urine after a meal of human blood. Nonstimulated isolated Malpighian tubules secrete small amounts of cAMP that increase about 10-fold after the addition of 5-hydroxytryptamine (5-HT). 5-HT is known to mimic R. prolixus diuretic hormone. The present findings demonstrate that 5-HT also acts via cAMP. The presence of cAMP in the rectal sac of the insect could be of importance in the differentiation of Trypanosoma cruzi and in the cycle of Chagas disease.

Social and Ecological Aspects of Resettlement and Villagization among the Konso of Southwestern Ethiopia.

TEKLEMARIAM AYELE(2) This is a study of the changing settlement and land use patterns of the Konso in three peasant associations in southwestern Ethiopia and an evaluation of their attitudes toward government-sponsored villagization in the lowlands. Over the years, the Konso have moved spontaneously from the overpopulated highlands toward lower elevations and have recently begun to cultivate on the Yanda plain, but without settling there. Fear of tropical diseases, armed conflict with pastoralists and the Konso perception of lowland living continue to be powerful deterrents to settlement in the lowlands. Major objectives of the government villagization programme are unlikely to be achieved in the Konso area and may instead lead to disaster unless this programme is drastically revised to provide suitable conditions for resettlement and to meet the specific needs of the population.

Intracellular signaling transduction in the differentiation of Trypanosoma cruzi: role of cAMP.

We have studied the cell differentiation of Trypanosoma cruzi in an vitro system that allows the transformation of epimastigotes into metacyclic trypomastigotes. Intracellular cAMP levels of epimastigotes increased 3 fold prior to their differentiation into metacyclics where cAMP remained elevated 3.7 fold with respect to epimastigotes. We also observed a 3 fold increase in the specific activity of cAMP-binding of metacyclics crude homogenates. This activity resided in a cAMP-binding receptor protein (CARPT) which was different from the typical cAMP-binding subunits (RI and RII) of cAMP-dependent protein kinases, as shown by the use of polyclonal antibodies prepared against these two types of proteins. Anti-RI antibodies did not react with CARPT, and anti-RII antibodies gave a cross reaction with CARPT which was at least 1,000 fold less sensitive than the one shown by the homologous antigen. On Western blots CARPT displayed a major band with Mr = 87,000 instead of Mr = 56,000 for RII. These studies implicate that cAMP may act as a mediator of the cell differentiation of T. cruzi by a mechanism involving a novel type of cAMP-binding receptor.

Cyclic AMP as an inducer of the cell differentiation of Trypanosoma cruzi.

The addition to epimastigotes cultures of T. cruzi, of either cAMP, monobutyryl-cAMP, dibutyryl-cAMP, 8-Br-cAMP (at 2 mM each), or the cAMP-phosphodiesterase inhibitor, papaverine (0.2 mM), promoted the in vitro differentiation of these parasite forms into metacyclics. This effect of cAMP may also be exerted in vivo in the insect vector, since cAMP was detected in the urine and in the Malpighi secretion fluids of Rodnius prolixus.