Seasonal proteome variation in intertidal shrimps under a natural setting: Connecting molecular networks with environmental fluctuations.

The ability of intertidal organisms to maintain their performance via molecular and physiological adjustments under low tide, seasonal fluctuations and extreme events ultimately determines population viability. Analyzing this capacity in the wild is extremely relevant since intertidal communities are under increased climate variability owing to global changes. We addressed the seasonal proteome signatures of a key intertidal species, the shrimp Palaemon elegans, in a natural setting. Shrimps were collected during spring and summer seasons at low tides and were euthanized in situ. Environmental variability was also assessed using hand-held devices and data loggers. Muscle samples were taken for 2D gel electrophoresis and protein identification through mass spectrometry. Proteome data revealed that 55 proteins (10.6% of the proteome) significantly changed between spring and summer collected shrimps, 24 of which were identified. These proteins were mostly involved in cytoskeleton remodelling, energy metabolism and transcription regulation. Overall, shrimps modulate gene expression leading to metabolic and structural adjustments related to seasonal differences in the wild (i.e. abiotic variation and possibly intrinsic cycles of reproduction and growth). This potentially promotes performance and fitness as suggested by the higher condition index in summer-collected shrimps. However, inter-individual variation (% coefficient of variation) in protein levels was quite low (min-max ranges were 0.6-8.3% in spring and 1.2-4.8% in summer), possibly suggesting reduced genetic diversity or physiological canalization. Protein plasticity is relevant to cope with present and upcoming environmental variation related to anthropogenic forcing (e.g. global change, pollution) but low inter-individual variation may limit evolutionary potential of shrimp populations.

Proteomic changes driven by urban pollution suggest particulate matter as a deregulator of energy metabolism, mitochondrial activity, and oxidative pathways in the rat brain.

The adverse effects of air pollution have been long studied in the lung and respiratory systems, but the molecular changes that this causes at the central nervous system level have yet to be fully investigated and understood. To explore the evolution with time of protein expression levels in the brain of rats exposed to particulate matter of different sizes, we carried out two-dimensional gel electrophoresis followed by determination of dysregulated proteins through Coomassie blue staining-based densities (SameSpots software) and subsequent protein identification using MALDI-based mass spectrometry. Expression differences in dysregulated proteins were found to be statistically significant with p-value <0.05. A systems biology-based approach was utilized to determine critical biochemical pathways involved in the rats' brain response. Our results suggest that rats' brains have a particulate matter size dependent-response, being the mitochondrial activity and the astrocyte function severely affected. Our proteomic study confirms the dysregulation of different biochemical pathways involving energy metabolism, mitochondrial activity, and oxidative pathways as some of the main effects of PM exposure on the rat brain. SIGNIFICANCE: Rat brains exposed to particulate matter with origin in car engines are affected in two main areas: mitochondrial activity, by the dysregulation of many pathways linked to the respiratory chain, and neuronal and astrocytic function, which stimulates brain changes triggering tumorigenesis and neurodegeneration.

Dithiothreitol-based protein equalization technology to unravel biomarkers for bladder cancer.

This study aimed to assess the benefits of dithiothreitol (DTT)-based sample treatment for protein equalization to assess potential biomarkers for bladder cancer. The proteome of plasma samples of patients with bladder carcinoma, patients with lower urinary tract symptoms (LUTS) and healthy volunteers, was equalized with dithiothreitol (DTT) and compared. The equalized proteomes were interrogated using two-dimensional gel electrophoresis and matrix assisted laser desorption ionization time of flight mass spectrometry. Six proteins, namely serum albumin, gelsolin, fibrinogen gamma chain, Ig alpha-1 chain C region, Ig alpha-2 chain C region and haptoglobin, were found dysregulated in at least 70% of bladder cancer patients when compared with a pool of healthy individuals. One protein, serum albumin, was found overexpressed in 70% of the patients when the equalized proteome of the healthy pool was compared with the equalized proteome of the LUTS patients. The pathways modified by the proteins differentially expressed were analyzed using Cytoscape. The method here presented is fast, cheap, of easy application and it matches the analytical minimalism rules as outlined by Halls. Orthogonal validation was done using western-blot. Overall, DTT-based protein equalization is a promising methodology in bladder cancer research.

Unparalleled sample treatment throughput for proteomics workflows relying on ultrasonic energy.

We report on the new microplate horn ultrasonic device as a powerful tool to speed proteomics workflows with unparalleled throughput. 96 complex proteomes were digested at the same time in 4min. Variables such as ultrasonication time, ultrasonication amplitude, and protein to enzyme ratio were optimized. The "classic" method relying on overnight protein digestion (12h) and the sonoreactor-based method were also employed for comparative purposes. We found the protein digestion efficiency homogeneously distributed in the entire microplate horn surface using the following conditions: 4min sonication time and 25% amplitude. Using this approach, patients with lymphoma and myeloma were classified using principal component analysis and a 2D gel-mass spectrometry based approach. Furthermore, we demonstrate the excellent performance by using MALDI-mass spectrometry based profiling as a fast way to classify patients with rheumatoid arthritis, systemic lupus erythematosus, and ankylosing spondylitis. Finally, the speed and simplicity of this method were demonstrated by clustering 90 patients with knee osteoarthritis disease (30), with a prosthesis (30, control group) and healthy individuals (30) with no history of joint disease. Overall, the new approach allows profiling a disease in just one week while allows to match the minimalism rules as outlined by Halls.

A cost-effective method to get insight into the peritoneal dialysate effluent proteome.

Protein depletion with acetonitrile and protein equalization with dithiothreitol have been assessed with success as proteomics tools for getting insight into the peritoneal dialysate effluent proteome. The methods proposed are cost-effective, fast and easy of handling, and they match the criteria of analytical minimalism: low sample volume and low reagent consumption. Using two-dimensional gel electrophoresis and peptide mass fingerprinting, a total of 72 unique proteins were identified. Acetonitrile depletes de PDE proteome from high-abundance proteins, such as albumin, and enriches the sample in apolipo-like proteins. Dithiothreitol equalizes the PDE proteome by diminishing the levels of albumin and enriching the extract in immunoglobulin-like proteins. The annotation per gene ontology term reveals the same biological paths being affected for patients undergoing peritoneal dialysis, namely that the largest number of proteins lost through peritoneal dialysate are extracellular proteins involved in regulation processes through binding. SIGNIFICANCE: Renal failure is a growing problem worldwide, and particularly in Europe where the population is getting older. Up-to-date there is a focus of interest in peritoneal dialysis (PD), as it provides a better quality of life and autonomy of the patients than other renal replacement therapies such as haemodialysis. However, PD can only be used during a short period of years, as the peritoneum lost its permeability through time. Therefore to make a breakthrough in PD and consequently contribute to better healthcare system it is urgent to find a group of biomarkers of peritoneum degradation. Here we report on two cost-effective methods for protein depletion in peritoneal dialysate effluent (PDE). The use of ACN and DTT over PDE to deplete high abundant proteins or to equalize the concentration of proteins, respectively, performs well and with similar protein profiles than when the same chemicals are used in human plasma samples. ACN depletes de PDE proteome from large proteins, such as albumin, and enriches the sample in apolipoproteins. DTT equalizes the PDE proteome by diminishing the levels of large proteins such as albumin and enriching the extract in immunoglobulins. Although the number and type of proteins identified are different, the annotation per gene ontology term reveals the same biological paths being affected for patients undergoing peritoneal dialysate. Thus, the largest number of proteins lost through peritoneal dialysate belongs to the group of extracellular proteins involved in regulation processes through binding. As for the searching of biomarkers, DTT seems to be the most promising of the two methods because acts as an equalizer and it allows interrogating more proteins in the same sample.

Ocean warming alters cellular metabolism and induces mortality in fish early life stages: A proteomic approach.

Climate change has pervasive effects on marine ecosystems, altering biodiversity patterns, abundance and distribution of species, biological interactions, phenology, and organisms' physiology, performance and fitness. Fish early life stages have narrow thermal windows and are thus more vulnerable to further changes in water temperature. The aim of this study was to address the sensitivity and underlying molecular changes of larvae of a key fisheries species, the sea bream Sparus aurata, towards ocean warming. Larvae were exposed to three temperatures: 18°C (control), 24°C (warm) and 30°C (heat wave) for seven days. At the end of the assay, i) survival curves were plotted for each temperature treatment and ii) entire larvae were collected for proteomic analysis via 2D gel electrophoresis, image analysis and mass spectrometry. Survival decreased with increasing temperature, with no larvae surviving at 30°C. Therefore, proteomic analysis was only carried out for 18°C and 24°C. Larvae up-regulated protein folding and degradation, cytoskeletal re-organization, transcriptional regulation and the growth hormone while mostly down-regulating cargo transporting and porphyrin metabolism upon exposure to heat stress. No changes were detected in proteins related to energetic metabolism suggesting that larval fish may not have the energetic plasticity needed to sustain cellular protection in the long-term. These results indicate that despite proteome modulation, S. aurata larvae do not seem able to fully acclimate to higher temperatures as shown by the low survival rates. Consequently, elevated temperatures seem to have bottleneck effects during fish early life stages, and future ocean warming can potentially compromise recruitment's success of key fisheries species.

Oral health-related quality of life before hematopoietic stem cell transplantation.

OBJECTIVES: This study was planned to evaluate the impact of oral health on the quality of life (QoL) of patients undergoing hematopoietic stem cell transplantation (HSCT). MATERIAL AND METHODS: We assessed 200 patients divided into two paired groups: 100 patients prior to HSCT (SG) and 100 healthy volunteers (CG). We applied the Oral Health Impact Profile instrument, which is based on the biopsychosocial problem gradation of World Health Organization (WHO) and relates oral health problems with QoL according to seven dimensions. RESULTS: Fourteen patients in SG were referred for extraction of one to eight teeth, mostly due to deep caries with risk of pulpal infection and possible spread of infection via blood (r = 0.59, p = 0.000). The presence of severely compromised teeth by extensive decay correlated with Oral Health Impact Profile (OHIP-14). The Mann-Whitney test showed a significant difference between SG and CG in the following dimensions: functional limitation (p < 0.001), physical pain (p = 0.025), physical disability (p = 0.016), and social disability (p = 0.01). CONCLUSIONS: The impact of oral health on QoL of onco-hematologic patients is weak but is greater as compared to healthy ones. Nevertheless, a significant impact is seen in patients with severely compromised teeth. CLINICAL RELEVANCE: The negligence of oral care, proper hygiene, and the search for dental care may increase the risk for local and systemic infections.

Ultrasonography as a complementary exam in the diagnosis of oral arteriovenous malformation.

The Doppler ultrasonography (DU) in cases of arteriovenous malformations (AVMs) is not widely use by dentists and there are a lack of information on the topic in the literature. AVM is common in the region of the head and neck and are commonly confused with hemangiomas (congenital). Appropriate classification is essential for therapeutic decision. The diferential diagnosis is based on clinical history, diascopy, and, if necessary, diagnostic imaging. This article present two cases of oral AVM in which DU was crucial in detecting a venous and/or arterial component in purplish lesions in the tongue and buccal mucosa, with positive diascopy. In our cases, after DU, we found a predominance of blood component within the lesion and therefore both patients were referred to the head and neck surgeon for surgical removal of the lesion. Only in the presence of a venous component does outpatient treatment become feasible. Given the predominance of the arterial component, outpatient procedures are contraindicated. Therefore DU is an important supplementary test, being of great importance in the clinical decision and treatment plan for oral AVMs and should become a routine part of the dentist front of vascular lesions of medium to large size.

A journey through PROTEOSONICS.

Ultrasonic energy is gaining momentum in Proteomics. It helps to shorten many proteomics workflows in an easy and efficient manner. Ultrasonic energy is nowadays used for protein extraction, solubilisation and cell disruption, to speed protein identification, protein quantification, peptide profiling, metal-protein complexes characterisation and imaging mass spectrometry. The present review gives a perspective of the latest achievements in ultrasonic-based sample treatment for proteomics as well as provides the basic concepts and the tools of the trade to efficiently implement this tool in proteomics labs.

A comprehensive factorial design study of variables affecting protein extraction from formalin-fixed kidney tissue samples.

Formalin-fixed tissues are an important source of biological samples for biomedical research. However, proteomics analysis of formalin-fixed tissues has been set aside by formalin-induced protein modifications, which reduce protein extraction efficiency. In this study, a two level full factorial experimental design (2(4)) was used to determine the effects of the extracting conditions in the efficiency of protein recovery from formalin-fixed kidney samples. The following variables were assessed: temperature of extraction, pH of extraction, composition of the extracting buffer and the use ultrasonic energy applied with probe. It is clearly demonstrated that when hating and ultrasonic energy are used in conjunction, a 7-fold increase (p < 0.05) in protein extraction is obtained if compared to extracting conditions for which neither heating nor ultrasonic energy are used. The optimization study was done following the amount of protein extracted by UV (Nanodrop(®) technology, protein ABS at 280 nm) and by 1D SDS-PAGE. Extracts obtained with the optimized conditions were subjected to LC-MALDI MS/MS. A total of 112 proteins were identified.

Opposite effects of substance P fragments C (anxiogenic) and N (anxiolytic) injected into dorsal periaqueductal gray.

Recent findings implicating neurokinins in the expression of anxiety-like behaviors have stimulated interest in the participation of these neuropeptides in the dorsal periaqueductal gray matter (dPAG), one of the main output regions of the brainstem for the expression of defense reaction. Studies on the behavior of rats submitted to the elevated plus-maze test in this laboratory have shown that microinjections of substance P into the dorsal periaqueductal gray produce anxiogenic-like effects. Now, we analyze what portion of the molecule of substance P is responsible for these effects through the examination of the action of its C- and N-terminus fragments (6-11 and 1-7) in the elevated plus-maze. We also investigated whether these effects are influenced by prior treatment with the tachykinin NK(1) receptor antagonist 17-beta-hydroxy-17-alpha-ethynyl-5alpha-androstanol[3,2-b]pyrimido[1,2-a]benzimidazole (WIN51,708). To this end, rats were implanted with a cannula in the dorsal periaqueductal gray and injected 1 week later with equimolar doses (17.5 and 35 pmol) of either C- or N-fragments of substance P and tested in the elevated plus-maze. The results show that the C-terminal fragment has an anxiogenic profile of effects, including reduction in the number of entries and time spent in the open arms of the maze, plus increases in scanning, stretched-attend posture, head dipping and flat-back approach. On the other hand, the N-terminal fragment produced opposite effects, namely, an increase in the number of entries and time spent in the open arms of the maze accompanied by an increase in end-arm activity, rearing and head dipping. The tachykinin NK(1) receptor antagonist WIN51,708 (20 mg/kg, i.p.) inhibited the effects of the carboxy-terminal of substance P while it did not change the effects of the N-terminal fragment. Microinjection of WIN51,708 (20 mg/kg, i.p.), by its own, did not produce any significant effects. Therefore, the results indicate that the anxiogenic effects of substance P injected into the dorsal periaqueductal gray are encoded by its carboxy-terminal sequence and due to its action on tachykinin NK(1) receptors.

Hyperanxiety produced by periaqueductal gray injection of chondroitin sulphate glycosaminoglycan.

We examined the effects of chondroitin sulphate C (CSC) on fear and anxiety parameters following injection of the glycosaminoglycan into the dorsal periaqueductal gray. Rats with chronically implanted cannulae were administered CSC (0.4 or 4.0 nmol) or vehicle (saline, 0.2 microl) and exposed to the elevated plus-maze test of emotionality. Intra-periaqueductal gray injection of CSC produced a dose-dependent anxiogenic effect as indicated by reduced entries into and time spent on the open arms, fewer excursions into the end of the open arms and by increased stretched attend posture, flat back approach and closed arm peeping-out behaviour. The behavioural effects of CSC appeared to be anxioselective, since the glycosaminoglycan did not influence measures of general (exploratory) activity, such as number of entries into the enclosed arms and amount of scanning, rearing and grooming. The present results show that CSC can produce an anxiogenic-like profile after injection into the dorsal periaqueductal gray. This is the first such report implicating an endogenous matrix glycosaminoglycan in neural mechanisms governing fear and anxiety.

Place aversion induced by microinjections of C-fragment of substance P into the dorsal periaqueductal gray of rats is mediated by tachykinin NK1 receptors.

Neural circuits in the dorsal periaqueductal gray matter (dPAG) play an important role in the integration of defensive behavior. The neurokinin substance P causes conditioned place aversion when administered into this region. The present study examined whether these effects may be mimicked by its carboxy-terminal amino acid sequence and whether they are influenced by prior treatment with the tachykinin NK1 receptor antagonist WIN51,708. The behavioral testing apparatus is a circular open field consisting of 4 uniform quadrants that are equally preferred by the rats prior to drug treatments. For conditioning, rats received drug injections on three consecutive days and were placed into their assigned quadrant. The carboxy-terminal analog (17.5 pmol/0.2 microl) applied into the dPAG produced place aversion effects with reduced time spent in the drug-paired quadrant on the testing day. The effects of the carboxy-terminal analog was antagonized by pretreatment with WIN51,708 (20 mg/kg, i.p.). Microinjection of WIN51,708 (20 mg/kg, i.p.), by its own, did not produce significant effects. These findings suggest that previous reports showing conditioned place aversion effects of SP injected into the dPAG are encoded by its carboxy-terminal sequence and due to its action on tachykinin NK1 receptors.

Neurochemical mechanisms of the defensive behavior in the dorsal midbrain.

Some regions in the mesencephalon, such as dorsal periaqueductal gray, inferior colliculus and deep layers of superior colliculus have been grouped together as a continuous strip of midbrain structures involved in the integration of the different components of aversive states in the brain. In fact, escape behavior and defensive, or fear-like behavior often result when these sites are electrically or chemically stimulated. Moreover, the behavioral responses induced by stimulation of these structures are, in general, accompanied by increases in mean arterial blood pressure, heart rate and respiration, and by analgesia. Both the behavioral and autonomic consequences of electrical stimulation of the mesencephalic tectum was shown to be attenuated by minor tranquilizers, probably through enhancement of GABAergic neurotransmission. Besides GABAergic interneurons which exert a tonic inhibitory control on neural circuits responsible for the behavioral correlates of the aversion in the above-mentioned structures, several other mechanisms such as opioid, neuropeptides, serotonergic and excitatory amino acids have also been implicated in the regulation of these processes. As to the analgesia that accompanies these aversive states it is mediated by non-opioid mechanisms, particularly by serotonergic ones through 5-HT2 receptors. Now, efforts have been made to characterize the mode of action of these neurotransmitters on their multiple receptors and how they interact with each other to produce or regulate the neural substrates of aversion in the midbrain.

Anxiogenic effects of substance P and its 7-11 C terminal, but not the 1-7 N terminal, injected into the dorsal periaqueductal gray.

The dorsal periaqueductal gray matter (DPAG) is one of the main output regions of the brainstem for the expression of defense reaction. Recent findings implicating neurokinins in the expression of fear or anxiety-like behaviors, have stimulated interest in the participation of these neuropeptides in the generation of aversive states in the dorsal periaqueductal gray matter. Analyses of traditional measures of the behavior of rats submitted to the elevated plus-maze test in this laboratory have shown that microinjections of substance P (SP) into the DPAG produce anxiogenic-like effects. The present study employs an ethological analysis of the behavior of animals in this test to investigate the involvement of substance P (SP) and its C- and N- fragments (7-11 and 1-7) in the expression of the different aspects of fear upon injection into the DPAG. To this end, rats were implanted with a cannula in the DPAG and injected one week later with 35 and 70 pmol of either substance P, or C- or N- SP fragments and tested immediately afterwards in the elevated plus-maze. The results show that SP and its C terminal fragment, produced increases in scanning, stretched attend posture, head dipping and flat-back approach, whereas the fragment N terminal produced only an increase in rearing. Therefore, the effects of SP and its C terminal fragment were associated to risk assessment behavior, whereas those of N terminal fragment were related to vertical exploratory activity. The results indicate that SP produces anxiogenic effects through activation of neural substrates of aversion in the DPAG and that this effect is probably related to its C terminal fragment.

Aversive effects of the C-fragment of Substance P in the dorsal periaqueductal gray matter.

There has been an increasing interest in the role of neuropeptides in the integration of brain functions. Besides the well-known positive-reinforcing effects of Substance P (SP) in prosencephalic regions, a role of this neuropeptide in the generation of aversive states in mesencephalic structures has also been envisaged. Evidence from a previous study suggests an involvement of SP in the neural substrates of aversion in the dorsal periaqueductal gray matter (DPAG). In the present study, we investigate whether N- and C-terminal fragments of Substance P are responsible for the effects produced by microinjections of SP into the dorsal periaqueductal gray. The results show that SP and its C-terminal fragment SP(7-11) produced a behavioral activation with increases in locomotor activity, grooming, and rearings, while the N-terminal fragment SP(1-7) produced only an increase in vertical exploratory activity. The effects were more pronounced with intermediate doses of SP and its C-fragment, confirming the characteristic bell-shaped dose-effect function of this neuropeptide. The proaversive effects observed with DPAG microinjections of these neuropeptides in the present study gain further relevance when combined with previous reports showing unconditioned and conditioned aversive effects following DPAG microinjections of SP in the place aversion and the elevated plus maze tests, two widely used animal models of anxiety. These results confirm previous data showing that SP has a modulatory role in the DPAG and that its effects are probably due to its C-terminal fragment.

Estudio de individuos con serología positiva para chagas detectados en el banco de sangre del Hospital Interzonal General de Agudos, Mar del Plata / Study of subjects with positive serlogy for chaga's disease detected in the blood bank of the Hospital Interzonal General de Agudos, Mar del Plata

Objetivo: Partiendo del consenso científico-social que la tripanosomiasis americana (enfermedad de Chagas) en un desafio como problema endémico aún no resuelto, e insuficientemente evaluado, se procedió a investigar las características de la población que donó sangre en nuestro hospital entre Octubre y Junio 1992 en integrantes de la cual se detectaron reacciones suerológicas positivas para esa enfermedad. Diseño: Encuesta epidemiológica, del tipo "muestra consecutiva", por interrogatório y examen clínico sobre la base de diagnóstico parasitario positivo en serie de casos. Sede del estudio: Banco de sangre hospitalario y consultorio de clínica médica, anexo a cardiología. Pacientes: Muestra de 113 personas con suerología positiva para la enfermedad de Chagas, por hemaglutinación y prueba de inmunofluorescencia, sobre un total de 3409 dadores (prevalencia, 3//). Fueron citados la encuesta 96 de los cuales concurrieron 33 (34,5//). Resultantes epidemiológicos: Las edades de los pacientes se situaron entre 24 y 57 años; media 45 años. 25 hombres (76// y 8 mujeres (27//) provenían de la provincia de Santiago del Estero. 22 (73//) eran nativos de áreas rurales y 16 (53//) habian vivido en casas de barro. 26 (79//) conocían la vinchuca y 21 (67//) no conocían la enfermedad de Chagas. 31 (95//) habían donado sangre anteriormente. Resultados clínicos: En 11 pacientes (33,5//), todos hombres se encontraton alteraciones electrocardiográficas, prevaleciendo la bradicardia sinusal (n=4,36,6//). En 4 pacientes el índice cardiotorácico (radiografia) fue mayor a o,5. En 27 pacientes (82// al examen clínico reveló normalidad detectable en tal exploración. 16 (48,5//) se mostraron asintomaticos. Conclusiones: Casi todos los pacientes habían donado sangre con anterioridad configurando el riesgo de haber trasmitido la enfermedad de Chagas. La mayoria conocia la vinchuca pero ignoraba su relación con la enfermedad de Chagas y desconocian la naturaleza evolutiva de la misma. El 82// de la muestra en estudio se dio con estudio de normalidad. La alteración electrocardiográica prevalente fue la bradicardia sinusal. Se impone la vigilancia longitudinal y eventual tratamiento de los pacientes sueropositivos para tripanosomiasis americana

Estudio de individuos con serología positiva para chagas detectados en el banco de sangre del Hospital Interzonal General de Agudos, Mar del Plata / Study of subjects with positive serlogy for chagas disease detected in the blood bank of the Hospital Interzonal General de Agudos, Mar del Plata

Objetivo: Partiendo del consenso científico-social que la tripanosomiasis americana (enfermedad de Chagas) en un desafio como problema endémico aún no resuelto, e insuficientemente evaluado, se procedió a investigar las características de la población que donó sangre en nuestro hospital entre Octubre y Junio 1992 en integrantes de la cual se detectaron reacciones suerológicas positivas para esa enfermedad. Diseño: Encuesta epidemiológica, del tipo "muestra consecutiva", por interrogatório y examen clínico sobre la base de diagnóstico parasitario positivo en serie de casos. Sede del estudio: Banco de sangre hospitalario y consultorio de clínica médica, anexo a cardiología. Pacientes: Muestra de 113 personas con suerología positiva para la enfermedad de Chagas, por hemaglutinación y prueba de inmunofluorescencia, sobre un total de 3409 dadores (prevalencia, 3//). Fueron citados la encuesta 96 de los cuales concurrieron 33 (34,5//). Resultantes epidemiológicos: Las edades de los pacientes se situaron entre 24 y 57 años; media 45 años. 25 hombres (76// y 8 mujeres (27//) provenían de la provincia de Santiago del Estero. 22 (73//) eran nativos de áreas rurales y 16 (53//) habian vivido en casas de barro. 26 (79//) conocían la vinchuca y 21 (67//) no conocían la enfermedad de Chagas. 31 (95//) habían donado sangre anteriormente. Resultados clínicos: En 11 pacientes (33,5//), todos hombres se encontraton alteraciones electrocardiográficas, prevaleciendo la bradicardia sinusal (n=4,36,6//). En 4 pacientes el índice cardiotorácico (radiografia) fue mayor a o,5. En 27 pacientes (82// al examen clínico reveló normalidad detectable en tal exploración. 16 (48,5//) se mostraron asintomaticos. Conclusiones: Casi todos los pacientes habían donado sangre con anterioridad configurando el riesgo de haber trasmitido la enfermedad de Chagas. La mayoria conocia la vinchuca pero ignoraba su relación con la enfermedad de Chagas y desconocian la naturaleza evolutiva de la misma. El 82// de la muestra en estudio se dio con estudio de normalidad. La alteración electrocardiográica prevalente fue la bradicardia sinusal. Se impone la vigilancia longitudinal y eventual tratamiento de los pacientes sueropositivos para tripanosomiasis americana (AU)