Contribución de la prueba rápida NS1 e IgM al diagnóstico de dengue en Colombia en el periodo pre-zika

Objetivo: Se considera que el diagnóstico del dengue es fundamentalmente clínico; sin embargo, las pruebas rápidas basadas en la detección de IgM o NS1/IgM están siendo utilizadas en los servicios de salud. Este estudio determinó la contribución de las pruebas rápidas al diagnóstico de dengue en un área endémica antes de la introducción del virus zika.Metodología: Diseño de corte transversal de pruebas diagnósticas realizado a partir del análisis secundario de un estudio previo en 14 instituciones de salud del Valle del Cauca. Se obtuvo información de 632 participantes con resultados de prueba rápida, diagnóstico clínico y pruebas de referencia ELISA NS1, ELISA IgM y RT-PCR. Se compararon la sensibilidad, especificidad, valores predictivos y razones de verosimilitud del uso solo, en serie, y paralelo de los componentes NS1, IgM, NS1/IgM de la prueba rápida y el diagnóstico clínico con las pruebas Q de Cochran y McNemar para datos pareados.Resultados: La sensibilidad del diagnóstico clínico (61,4% IC95% 56%-66,7%) fue superior a la de las pruebas rápidas (37% IC95% 29,6%-44,7%) (P<0,001). El uso en serie de la prueba NS1/IgM cuando el diagnóstico clínico fue negativo aumentó la sensibilidad a 79,5% y, el uso en serie cuando el diagnóstico clínico fue positivo aumentó la especificidad (de 66,3% a 98,7%). Sin embargo, este último disminuyó la sensibilidad a 32,2%. Todas las razones de verosimilitud negativas (LR-) fueron cercanas a 1; mientras que, el uso en serie cuando el diagnóstico clínico fue positivo tuvo LR+ mayores de 10.Conclusión: El diagnóstico clínico tiene una mayor sensibilidad que las pruebas rápidas, pero por si solo no es suficiente para confirmar o descartar dengue. Un resultado positivo en pruebas rápidas en pacientes con diagnóstico clínico de dengue es útil para confirmarlo, pero un resultado negativo no lo descarta.

Identifying socio-ecological networks in rural-urban gradients: Diagnosis of a changing cultural landscape

Socio-ecological systems maintain reciprocal interactions between biophysical and socioeconomic structures. As a result of these interactions key essential services for society emerge. Urban expansion is a direct driver of land change and cause serious shifts in socio-ecological relationships and the associated lifestyles. The framework of rural-urban gradients has proved to be a powerful tool for ecological research about urban influences on ecosystems and on sociological issues related to social welfare. However, to date there has not been an attempt to achieve a classification of municipalities in rural-urban gradients based on socio-ecological interactions. In this paper, we developed a methodological approach that allows identifying and classifying a set of socio-ecological network configurations in the Region of Madrid, a highly dynamic cultural landscape considered one of the European hotspots in urban development. According to their socio-ecological links, the integrated model detects four groups of municipalities, ordered along a rural-urban gradient, characterized by their degree of biophysical and socioeconomic coupling and different indicators of landscape structure and social welfare. We propose the developed model as a useful tool to improve environmental management schemes and land planning from a socio-ecological perspective, especially in territories subject to intense urban transformations and loss of rurality.

Middle Miocene closure of the Central American Seaway

Uranium-lead geochronology in detrital zircons and provenance analyses in eight boreholes and two surface stratigraphic sections in the northern Andes provide insight into the time of closure of the Central American Seaway. The timing of this closure has been correlated with Plio-Pleistocene global oceanographic, atmospheric, and biotic events. We found that a uniquely Panamanian Eocene detrital zircon fingerprint is pronounced in middle Miocene fluvial and shallow marine strata cropping out in the northern Andes but is absent in underlying lower Miocene and Oligocene strata. We contend that this fingerprint demonstrates a fluvial connection, and therefore the absence of an intervening seaway, between the Panama arc and South America in middle Miocene times; the Central American Seaway had vanished by that time.

A novel, fully automated, observer-independent program for semiquantifying striatal ¹²³I-FP-CIT uptake

OBJECTIVE

To describe and validate a novel, fully automated program specifically designed for the semiquantification of striatal (123)I-FP-CIT uptake using volumes of interest (VOI) analysis.

MATERIAL AND METHODS

The proposed algorithm is based on a template that mimics the striatal (123)I-FP-CIT uptake in a healthy subjects, derived from defined anatomical VOIs available from WFU PickAtlas. Four SPECT studies of the anthropomorphic Alderson phantom filled with variable radioactive concentrations were acquired for the experimental validation. Experimental SPECT images were spatially normalized with respect to the previously created template. The binary VOIs corresponding to left caudate and putamen and right caudate and putamen, which were used to construct the template, were projected onto the experimental images to obtain the counts for these regions. To minimize the partial volume effect, a percentage of the voxels in these regions (threshold), rather than all of them, was used. A binary occipital VOI was used to quantify the non-specific uptake. Experimental binding potentials (BPs) were calculated from the counts in these regions. True BPs were calculated from aliquots taken from the solutions used to fill the phantom.

RESULTS

There were statistically significant differences in the experimental BP values (p<0.002) according to the percentage of voxels used. A highly significant correlation was achieved between true and experimental BP values, regardless of the percentage of voxels included for quantification.

CONCLUSIONS

Our novel, observer-independent program automatically performs the semiquantification of striatal (123)I-FP-CIT uptake in experimental studies.

Summing-coincidence corrections with Geant4 in routine measurements by γ spectrometry of environmental samples

In this work, we describe a method to quantitatively evaluate true-coincidence-summing effects by making use of the Geant4 toolkit, which incorporates an emulation of the radionuclide disintegration scheme. To check the capabilities of the method, we firstly validated the simulated corrections using the ones obtained experimentally for radionuclides such as (60)Co, (152)Eu and (133)Ba. Secondly, we evaluated the effect of summing corrections of some radionuclides included in two intercomparison exercises to conclude that the results were improved when utilising the method described here.

Critical comparison between modified Monier-Williams and electrochemical methods to determine sulfite in aqueous solutions

In the present work, known concentration of sulfite aqueous solutions in the presence and absence of gallic acid was measured to corroborate the validity of modified Monier-Williams method. Free and bound-sulfite was estimated by differential pulse voltammetry. To our surprise, the modified Monier-Williams method (also known as aspiration method) showed to be very inaccurate for free-sulfite, although suitable for bound-sulfite determination. The differential pulse approach, using the standard addition method and a correction coefficient, proved to be swift, cheap, and very precise and accurate.

Spatiotemporal distribution of microbial communities in a coastal, sandy aquifer system (Doñana, SW Spain)

The aquifer system of Doñana (SW Spain) represents the most important freshwater source in the Doñana Natural Area. Its spatiotemporal dynamics favours the hydrological connection between surface and subsurface ecosystems, and promotes matter fluxes among the different terrestrial and aquatic systems present here. This aquifer has been intensively studied from a hydrogeological point of view but little is known from an ecological perspective. In order to understand the ecological roles played by microbial communities in this system, we conducted a long-term seasonal study of bacterial abundance, cell biomass, bacterial biomass and functional activities over a 2-year period. Bacterial abundance ranged between 2.11 +/- 1.79 x 10(5) and 8.58 +/- 6.99 x 10(7) bacteria mL(-1) groundwater, average cell biomass was estimated to be 77.01 +/- 31.56 fgC and bacterial biomass varied between 8.99 +/- 4.10 x 10(-2) and 5.65 +/- 0.70 microgC mL(-1). Iron-related bacteria showed the highest activities among the functional groups studied. Moreover, among the variables that usually control spatial distributions of microbial communities in aquifer systems, depth did not have a relevant effect on this aquifer, at least in the range of depths studied, but grain size, probably due to its direct effects on hydrogeological parameters, such as permeability or porosity, appeared to exert moderate control, principally in terms of bacterial abundance. Finally, significant seasonal differences in the means of these microbiological variables were also observed; temperature seems to be the main factor controlling the temporal distribution of microbial communities in this aquifer system.

Spatiotemporal distribution of microbial communities in a coastal, sandy aquifer system (Doñana, SW Spain)

The aquifer system of Doñana (SW Spain) represents the most important freshwater source in the Doñana Natural Area. Its spatiotemporal dynamics favours the hydrological connection between surface and subsurface ecosystems, and promotes matter fluxes among the different terrestrial and aquatic systems present here. This aquifer has been intensively studied from a hydrogeological point of view but little is known from an ecological perspective. In order to understand the ecological roles played by microbial communities in this system, we conducted a long-term seasonal study of bacterial abundance, cell biomass, bacterial biomass and functional activities over a 2-year period. Bacterial abundance ranged between 2.11 +/- 1.79 x 10(5) and 8.58 +/- 6.99 x 10(7) bacteria mL(-1) groundwater, average cell biomass was estimated to be 77.01 +/- 31.56 fgC and bacterial biomass varied between 8.99 +/- 4.10 x 10(-2) and 5.65 +/- 0.70 microgC mL(-1). Iron-related bacteria showed the highest activities among the functional groups studied. Moreover, among the variables that usually control spatial distributions of microbial communities in aquifer systems, depth did not have a relevant effect on this aquifer, at least in the range of depths studied, but grain size, probably due to its direct effects on hydrogeological parameters, such as permeability or porosity, appeared to exert moderate control, principally in terms of bacterial abundance. Finally, significant seasonal differences in the means of these microbiological variables were also observed; temperature seems to be the main factor controlling the temporal distribution of microbial communities in this aquifer system.

[Gender-related differences in functional assessment of serotonergic system in healthy young subjects]

INTRODUCTION

Prolactin stimulation test with serotonergic stimulants has been widely used in the study of diverse psychiatric disorders. However, the characterization of this response in normal subjects is still incomplete.

OBJECTIVE

To compare the response to serotonin stimulation using dexfenfluramine, a specific serotonergic agent, in young healthy men and women, controlling the menstrual cycle.

METHODS

A total of 10 women and 9 men, who were given 30 mg of dexfenfluramine orally, were studied and their levels of prolactin were measured on an hourly basis for a five-hour period. Baseline, maximum and delta values of prolactin were compared for both groups.

RESULTS

According to the age groups studied (mean age for men: 19.9 +/- 2.5 years old; mean age for women: 20 +/- 1.5 years old), the prolactin maximum level and the response to prolactin (DPRL) were significantly higher in women (p-values: 0.02 and 0.04, respectively).

CONCLUSIONS

Young healthy women show a greater response to stimulation with dexfenfluramine than young healthy men. Clinical and biological implications of this observation are discussed in the context of the currently available research papers.

Clozapine may partially compensate for task-related brain perfusion abnormalities in risperidone-resistant schizophrenia patients

BACKGROUND

Previous reports show different cerebral activity patterns during treatment with clozapine and typical neuroleptics. However, to date no study has directly compared the brain activity patterns while subjects are undergoing treatment with clozapine and other atypical antipsychotics. This comparison is of interest, given the probably different mechanism of action of clozapine in comparison with other atypicals.

OBJECTIVE

To assess the effect of clozapine on perfusion deviations still evident during treatment with risperidone.

METHODS

Here we used hexamethylene-propylenaminoxime single photon emission computed tomography to compare the perfusion patterns observed during the performance of a Stroop test in 10 patients sequentially treated with risperidone and clozapine, owing to a lack of response to the former, and in 10 healthy controls.

RESULTS

Patients on risperidone showed decreased perfusion as compared to controls in the medial prefrontal, middle cingulate and insular regions, as well as increased activities in brain stem and the posterior hippocampus. After receiving clozapine, the same patients showed an even wider prefrontal perfusion deficit and the brain stem was still hyperactive, but the abnormalities in the cingulate cortex, insula and hippocampus had disappeared. Clinical improvement was directly related to an increase in thalamic perfusion.

CONCLUSION

Clozapine may alleviate hyperactivity in the limbic system in schizophrenia and may facilitate activation of the regions involved in cognitive tasks to a greater degree than risperidone, as well as eliciting greater inhibition of the PF region.

Serotonin transporter polymorphism and fluoxetine effect on impulsiveness and aggression in borderline personality disorder

INTRODUCTION

Impulsiveness and aggressiveness are characteristics of borderline personality disorder and are associated to a serotoninergic system dysfunction. Serotonin transporter polymorphisms have been linked to aggressive and impulsive behaviors. The short allele (S) in depression is associated to a worse response to selective serotonin reuptake inhibitors (SSRI). This study aims to study these polymorphisms to predict the response of aggressive and impulsive behaviors to SSRIs in borderline personality disorder.

METHOD

Fifty-nine patients with DSM-IV borderline personality disorder in accordance with the International Personality Disorder Examination (IPDE) and without axis 1 disease were treated with flexible doses of fluoxetine for 12 weeks. The patients were evaluated with the Overt Aggression Scale Modified (OAS-M) at the beginning and at 2, 4, 8 and 12 weeks of treatment. Polymorphisms L and S of the serotonin transporter promoter region were determined. Response to fluoxetine of the LL carriers versus the S carriers (LS+SS) was compared.

RESULTS

LL carriers had a better response than S carriers in the reduction of total OAS-M scores and on the aggressiveness and irritability components of the OAS-M.

CONCLUSIONS

L-allele carriers responded better to fluoxetine than S carriers, in a similar way as in depression. The S allele may represent a common factor of bad response to SSRI in diseases associated to serotoninergic system dysfunction.

Solubilized Micellar Calcium Induced Low Methoxyl-Pectin Aggregation During Milk Acidification

Low methoxyl (LM) pectin was combined with 3-kDa molecular weight cut-off permeates from milk subjected to pH 6.7 to 5 and 7 degrees C or 40 degrees C with the objective of studying the effect of solubilized micellar calcium on viscoelastic properties of LM-pectin-milk mixes. Lowering the pH of skim milk with hydrochloric acid during ultrafiltration gradually promoted permeates to exhibit gel-like behavior when combined with LM-pectin. The onset of the gel-like behavior (G' > 1) occurred at a higher pH when permeates were obtained from milk filtered at 7 degrees C compared with 40 degrees C. As pH value during ultrafiltration approached 5 and regardless of temperature, G' for permeate-pectin mixes approached the same values (approximately 70 Pa) as G' for skim milk-pectin mixes. In all cases G' was highly correlated with free calcium concentration (r > 0.95). The gradual acidification of skim milk-LM-pectin using glucono-delta-lactone, promoted a sharp increase in storage modulus as pH approached 5.2 and a maximum G' increment (DeltaG') at pH approximately 4.9. From pH 4.9 to 4, G' continued to increase but at smaller increments. It was concluded that LM-pectin-casein micelle interaction in milk is a 2-step process: 1) solubilized micellar calcium dependent pectin-pectin interaction as pH approaches 5.0 to 4.9, and 2) pectin-casein micelle interaction in the 5.0-4.9 to 4.0 pH range.

Pyrrolizidine alkaloid level in Senecio bicolor (Wilid.) Tod, ssp. cineraria (DC.) from middle Europe

From Senecio bicolor, ssp. cineraria, cultivated in middle Europe, seven pyrrolizidine alkaloids (PA) were isolated and their structures elucidated by spectroscopical methods. Besides the already known senecionine, integerrimine, seneciphylline, jacobine, jacoline and jaconine the jacobine-acetate was found. On account of structure toxicity relationship all PA show toxic side-effects.

[Schizophrenic patients living in the community. Nursing referral]

The authors describe the clinical and socio-demograpaphic characteristics of schizophrenic patients who live out in the community. The authors study the clinical profile and the disabilities of those items derived from nursing. To do so, the authors made a random selection from persons diagnosed as schizophrenics who visited one of the five Mental Health Centers in the Sant Joan de Déu Hospital network's Mental Health Services. The authors evaluated sociodemographic characteristics, use of services, disabilities based on WHO-DAS, PANSS psychopathology, and LSP ability to function socially. Of the 231 patients included in this study group, 141 patients followed a psychiatrist only treatment program while 90, or 39%, followed a combined psychiatrist-nurse treatment program. Upon comparing these two groups, the authors observed that those patients who followed a combined treatment program had a higher score on the Negative PANSS test (*p < 0.005) which means they have many more difficulties to adequately carry out social functions in daily life activities. On the other hand, this group had lower scores on the WHO-DAS-IV Total test (*p < 0.001), on the WHO-DAS-IV Occupational Test (*p < 0.001), on the WHO-DAS-IV Familiar Test (*p < 0.005) and on WHO-DAS-IV Personal Care Test (*p < 0.005). The authors did not observe any significant results on the rest of the subscales nor on the LSP test.

Cognitive effects of precentral cortical stimulation for pain control: an ERP study

Electrical stimulation of the motor cortex (MCS) is a promising and increasingly used neurosurgical technique for the control of refractory neuropathic pain. Although its mechanisms of action remain unknown, recent functional imaging data suggest involvement of the thalamus, brainstem and anterior cingulate/orbitofrontal cortex. Since some of these areas are also implicated in higher cognitive functions, notably attentional processes, we analysed cognitive ERPs and behavioural performance during an "oddball" auditory detection task in patients submitted to this procedure. Eleven consecutive patients undergoing MCS because of neuropathic refractory pain, ranging in age from 25 to 71 years, were included in the study. ERPs were obtained in all cases both during the application ("MCS-on") and within the 10 min that followed discontinuation of the procedure ("MCS-off"). In five patients, ERPs could also be obtained just before the start of MCS. When the patients' sample was taken as a whole, there were no consistent effects of MCS on the ERPs. There was, however, a significant interaction of MCS action with the patients' age, reflecting a significant delay during MCS of the cognitive responses N2 and P3 (N200 and P300) in the group of patients older than 50 years exclusively. This effect was rapidly reversible after MCS discontinuation. No MCS-related changes were observed in the N1 component. At the individual level, the effect of MCS on the endogenous ERPs was highly variable, ranging from a total stability of ERPs (mostly in younger subjects) to latency differences of tens of milliseconds in the older group. These results, together with recent experiments showing P300 alteration during repetitive transcranial stimulation, suggest that motor cortex stimulation may interfere with relatively simple cognitive processes such as those underlying target detection, and that the risk of abnormal cognitive effects related to cortical stimulation may increase with age. Although the procedure appears on the whole remarkably safe, complementary neuropsychological studies in this category of patients are advised, as well as caution to possible adverse cognitive effects when using MCS in the elderly, notably in the presence of pre-existent cerebral lesions.

Maintenance of a laboratory colony of Cimex lectularius (Hemiptera: Cimicidae) using an artificial feeding technique

The in vitro maintenance technique described in this article has been used successfully to rear Cimex lectularius (L.) by feeding for >2 yr all nymphal stages and adults through parafilm "M" sealing film on different types of blood. Using this feeding technique, the subsequent egg production of female bedbugs was remarkably high. The blood was maintained at 37 degrees C to enhance the attachment of the bugs. The effect of anticoagulation methods for the blood meal was investigated, and heparinized blood was found the most suitable for feeding bugs. All stages of the bugs fed weekly on blood in the artificial feeding system remained attached for up to 0.5-1.0 h, until completion of their blood meals, and all reached engorged weights. More than 90% of the bugs fed artificially on whole blood, and they molted or laid eggs successfully.

Laryngeal effects of stimulation of rostral and ventral pons in the anaesthetized rat

In order to study the importance of two pontine regions modulating laryngeal resistance, electrical current or microinjections of glutamate (10-30 nl, 1-3 nmol) were made into the pontine parabrachial complex and the A5 region in spontaneously breathing anaesthetized rats. Two distinct patterns of laryngeal and respiratory responses were elicited. An increase of subglottal pressure was accompanied with an expiratory facilitatory response consisted of a decrease in both respiratory rate and phrenic nerve activity. A decrease of subglottal pressure was accompanied with an inspiratory facilitatory response consisted of an increase in both respiratory rate and phrenic nerve activity. The modification of laryngeal calibre occurred during both respiratory phases in most cases. The concomitant cardiovascular changes of these responses were also analyzed. Controls using guanethidine to block autonomic responses which might interact with respiratory control were also made. Histological analysis of stimulation sites showed a topographical organization of these responses: laryngeal constriction was evoked from Kölliker-Fuse, medial parabrachial nuclei and A5 region, whilst the laryngeal dilation was evoked from the lateral parabrachial nucleus.

Production and localization of Muc4/sialomucin complex and its receptor tyrosine kinase ErbB2 in the rat lacrimal gland

PURPOSE

To show the presence and forms of sialomucin complex (rat Muc4) and receptor tyrosine kinase ErbBs in the rat lacrimal gland and analyze for complexes of ErbB2 and its ligand Muc4.

METHODS

Northern blot analyses were used to identify sialomucin complex/Muc4 (SMC/Muc4) mRNA in rat lacrimal gland. Immunoblot analyses were performed to detect SMC/Muc4 and ErbBs. Sequential immunoprecipitation and immunoblot analyses were used to differentiate membrane and soluble forms of the SMC/Muc4 transmembrane subunit ASGP-2. Methacarn-fixed, paraffin-embedded sections of lacrimal glands from female adult rats were immunocytochemically stained using antisera to SMC/Muc4 and ErbBs to determine their relative locations in the gland. Colocalization of SMC/Muc4 and ErbB2 was confirmed by confocal immunofluorescence. Sequential immunoprecipitation and immunoblot were performed to analyze complexes of the SMC/Muc4 and ErbB2 in the lacrimal tissue.

RESULTS

Northern blot analyses of rat lacrimal glands, with a probe for SMC/Muc4, demonstrated the presence of a approximately 9-kb transcript, consistent with observations in other tissues. Similarly, immunoblot analyses with antibodies against both the transmembrane (ASGP-2) and mucin (ASGP-1) subunits showed the presence of the two SMC/Muc4 subunits in lysates from rat lacrimal gland. Significantly, two different forms of ASGP-2 were observed, a high-molecular-weight ( approximately 200-kDa) form and the more common 120- to 140-kDa form. Sequential immunoprecipitation and immunoblot analyses to differentiate membrane and soluble forms of SMC/Muc4 indicated that the high-molecular-weight form of ASGP-2 was predominantly associated with membranes, whereas the 120- to 140-kDa form was both membrane-associated and soluble. The lacrimal gland consists of acini connected by intercalated and interlobular ducts. Both acini and some intercalated ducts were stained by anti-ASGP-2 monoclonal antisera. Two patterns of acinar staining were observed: membrane staining at the borders of the epithelial cells and a granular staining within the cells. Staining of ductal surfaces with antibody to the cytoplasmic domain of ASGP-2 suggests that membrane SMC/Muc4 is being produced by the ductal cells and is not simply an adsorbed soluble product from the acinar cells. Immunoblot and immunocytochemical analyses demonstrated the presence of all four ErbBs, with ErbB2 showing the most widespread distribution, similar to that of SMC/Muc4. Immunofluorescence colocalization of membrane SMC/Muc4 and ErbB2 and coimmunoprecipitation of a complex of the two provided evidence of their association in membranes of lacrimal gland acinar cells.

CONCLUSIONS

SMC/Muc4 is produced by the rat lacrimal gland as both membrane and soluble forms, specifically associated with both acinar and ductal cells. Because sialomucin complex is also present in the ocular tear film, the rat lacrimal gland represents a second source of this mucin for the tear film, in addition to the corneal and conjunctival epithelia. Moreover, the presence of a complex of SMC/Muc4 and the receptor tyrosine kinase ErbB2 in lacrimal tissue suggests that SMC/Muc4 acts as a ligand for the receptor and has functions in the lacrimal gland other than that of a mucin.

Soliton compression in Brillouin fiber lasers

Pulse propagation in optical fibers may electrostrictively excite acoustic waves as a result of cladding Brillouin scattering, transversally propagating with respect to the fiber axis in the fiber's cladding, and mechanical coating. We show, for the first time to our knowledge, experimentally and theoretically that these transverse resonances within finite frequency ranges may cooperatively couple with the acoustic longitudinal modes of a fiber resonator, giving rise to stable trains of either spread or compressed three-wave Brillouin solitons and propose a first stability map for the rich four-wave dissipative dynamics.

Eimeria necatrix virus: intracellular localisation of viral particles and proteins

The presence of the Eimeria necatrix virus was investigated in the following life cycle stages: sporocysts, sporozoites, merozoites, and macrogametes. Electron microscopy revealed virus-like particles (VLPs) in sporozoites, which were purified from sporozoite extracts and used to raise polyclonal antibodies. Viral proteins were identified as RNA polymerase (95 kDa) and the major capsid protein (80 kDa). Polyclonal antibody was used to detect the intracellular localisation of VLPs and proteins. Immunoelectron microscopy and immunohistochemistry identified a viral protein of 95 kDa in all the E. necatrix stages studied, whereas the 80 kDa protein was found only in sporocysts and sporozoites. In addition, no VLPs were found in sporocysts. These results indicate that the synthesis of viral capsid proteins takes place during the early events of sporulation, and is then packaged into novel viruses during the late events. No VLPs were seen and no capsid proteins were found in the merozoites and macrogametes, whereas the 95 kDa RNA polymerase was present in both these stages. In addition, no VLPs or proteins were detected in chicken tissues.

Bioenergetics of juveniles of red swamp crayfish (Procambarus clarkii)

Procambarus clarkii is an endemic North American crayfish species that was introduced into Spain in 1973 for aquacultural and fishing purposes. Although P. clarkii is a well-studied species for commercial production, there is a great gap in the knowledge of the bioenergetics of juveniles. The aims of this study were to quantify the elements of the energy flow for juveniles of P. clarkii when fed in the laboratory on four different diets. The diets used were: (1) trade commercial feed; (2) various dried algal species; (3) dried Gammarus pulex; and (4) an equal mixture of algal species and G. pulex. The best energetic balance was obtained with diet 3 (greatest energy directed to production P=57%; least energetic investment in respiration R=31%, excretion U=9%, but highest energy loss via faeces F=4%). The poorest energetic balance was observed with diet 4 (P=26.3%; R=55.5%; U=14.7%, but lower energy loss in faeces F=3.5%). The mean O:N relationship was 1.37+/-2.15, implying marked protein catabolism. The utility of studying the bioenergetics of juvenile P. clarkii in laboratory conditions results in the formulation of testable hypotheses about ecological facts and the provision of new insights into the management of their populations in natural environments.

[The most significative parameters for the diagnosis of focal neuropathy of the cubital nerve in the elbow]

OBJECTIVE

Determine the diagnostic validity of the most usual neurophysiological procedures in the examination of compressive neuropathies and/or ulnar nerve entrapment at the elbow.

PATIENTS AND METHODS

A prospective observational study was carried out over a period of one year which included 19 patients with clinical features compatible with entrapment/compression of the ulnar nerve at the elbow, their neurophysiological diagnosis and surgical confirmation. We also studied 49 patients who were attended in our clinic for other reasons not related to disorders of the ulnar nerve. The variables studied were: maximum rate of motor conduction above the elbow; the amplitudes between spikes and the area between the first negative deflection and the last positive spike of the responses at the wrist and above the elbow.

RESULTS

In the group of persons without disorders of the ulnar nerve the average rate of motor conduction was 58.07 m/s, with a confidence interval of 53-65. In the group of patients with specific clinical features the average rate of motor conduction was 47.26 m/s, with a confidence interval of 43.74-50.77. No relation was found between age and pathology, although rate of motor conduction was related to the presence of pathology.

CONCLUSIONS

It was seen on logistical regression that the main variables for prediction of the presence or absence of pathology in a person were firstly motor conduction and secondly the amplitude index.

[Treatment of inoperable malignant gastric stenosis with self-expanding prosthesis]

We report two patients with inoperable malignant stenosis of gastric antrum who were treated with endoscopic placement of a 22 mm Wallstent metallic prosthesis. In one patient, the endoscope was introduced simultaneously with the prosthesis. Different types of pincers were introduced through the endoscope's canal, which aided the movement and placement of the prosthesis. In the other patient, to broaden the stenosis a pediatric endoscope was introduced with a guide inside the canal, which was held straight externally and which facilitated the positioning of the prosthesis. There were no complications and the patients were discharged after 48 hours able to follow a normal oral diet. Both patients are still living, six and four months respectively after the procedure.

Antibodies against Trypanosoma cruzi alkaline antigens are elicited in sera from acute but not chronic human chagasic patients

The aim of this work was to study the antibody response of acute and chronic chagasic patients against a Trypanosoma cruzi alkaline fraction (FI) in comparison with the reactivity against a T. cruzi acidic antigen, the main cystein proteinase of the parasite named cruzipain, and "natural" antigens. FI-specific antibodies were detected only during the acute phase of the infection and IgM was the main isotype produced, whereas cruzipain-specific antibodies were detected during all phases of the infection. By means of immunoblot and sequencing analysis we identified a 47-kDa FI proteic band recognized by IgM from acute chagasic patients as the T. cruzi glutamate dehydrogenase (GluDH). Furthermore, the antibody response against isolated GluDH showed similar characteristics as the one against FI. We also observed a strict association between the reactivity of IgM against FI and GluDH and IgM natural antibodies. However, reactivity against these alkaline antigens was not modified after absorption of natural antibodies in sera from acute chagasic patients, indicating that these parasite antigens are not recognized by the polyspecific natural antibodies. The most important goal of this report is that for the first time the T. cruzi antigen isoelectric point has been associated with its ability to trigger immunological memory, raising a novel antigen property that should be considered in the selection of antigens used in Chagas' disease diagnostic test and in the design of a vaccine against T. cruzi infection.

Self-expanding prostheses as a palliative method in treating advanced colorectal cancer

AIM

This work presents the results of the use of self-expanding prosthesis as a definitive palliative method for eliminating colorectal obstructions caused by advanced and unresectable tumours.

PATIENTS

A total of 41 cases were included (29 men, 12 women) with an average age of 70.12 years (range 46-95 years). All cases were showed symptoms of acute intestinal obstruction. Wallstent prostheses were inserted.

RESULTS

Locally unresectable colorectal tumours were disseminated in five cases, metastasis in 28 cases and other tumours in eight cases. In all patients the appropriate insertion was performed, eliminating the obstruction in 38 (92.6%) cases in 24-96 h. The morbidity rate was 6/41 cases (14.6%) with slight rectal discomfort in five and one case of bleeding. Posterior tolerance of the prostheses was good.

FOLLOW-UP

Two spontaneous rejections, three episodes of subocclusion because of faecal impact and two obstructions caused by an invasion of tumours occurred. Overall, 33 cases (80.4%) died within 1-18 months, average of 4.5 months survival.

CONCLUSIONS

Wallstent endoprostheses is a good alternative avoiding a colostomy and providing a good tolerance and comfort for the patient until death.

[Congenital defects of antithrombin III and proteins C and S during pregnancy]

We report 10 patients with congenital deficiencies of the natural anticoagulant proteins S, C and antithrombin III. Thirteen of a total of 30 pregnancies were managed at the perinatal branch of our department. We discuss the mechanism of action of these proteins and their role in thrombotic events. We analyze the most frequent thrombotic complications and we discuss the general guidelines for the investigation of a patient with a suspected congenital thrombophilia with special regard to its management during pregnancy, delivery and perinatal outcome.

[Somatosensory trigeminal evoked potentials after gingival stimulation of the mental nerve. Normal values]

OBJECTIVE

Somatosensory evoked potentials were recorded following unilateral stimulation of the mental nerve in the gum of 100 healthy volunteers aged between 17 and 22 years.

METHODS AND RESULTS

Responses were recorded until 100 ms with electrodes placed over the scalp (C5/C6) referenced to central frontal (Fz). In 10 subjects, simultaneous recordings were made in masticatory and facial muscles to detect possible muscle artefacts. Stimulation was effected using a specially-designed stimulator adaptable to each individual. Contralateral responses consisted of four very constant deflexions (N12, P19, N26 and P35) forming a W-shaped complex of mean duration 31.27 ms. Tables of normality were compiled for latencies and amplitudes with confidence intervals of 99.8% reliability. Constancy of deflexions, stability of response (by serial studies), and possible sexual differences were also studied. Muscle artefacts were ruled out, and the participation of the mental nerve in the genesis of the responses was confirmed.

CONCLUSION

We consider the proposed method a reliable alternative to other procedures used to obtain TEPs.

Selection and development of a Spanish precocious strain of Eimeria necatrix

A precocious line of Eimeria necatrix (PEN E-281/20) with an abbreviated life cycle was derived from a Spanish field strain (E-281) by repeated passages of the first shed oocysts recovered from the caecal contents of previously infected chickens. After 20 passages, the 'useful' prepatent period (time from infection to obtaining sufficient oocysts to repassage) of the parasite was reduced by 30 h (from 148 to 118 h). The earliest oocysts found in the caecal content were 114 h postinfection (hpi), on the 19th passage. The pathogenicity of the parasite was reduced in comparison with the parent strain, its immunogenicity against homologous and heterologous strains was maintained and its reproductive capacity was similar to or higher than that of the parent strain. Compared with the parent strain, the second generation of schizonts was reduced in size (reduced pathogenicity), third generation schizonts were bigger and with more merozoites (maintenance of the reproductive index) and the life cycle progressed faster from the second generation of schizonts (reduction of prepatent period). Complete second schizogony, from trophozoites to mature schizonts was observed frequently in the caeca of birds infected with both parent and precocious lines.

Quantification of busulfan in plasma by gas chromatography-mass spectrometry following derivatization with tetrafluorothiophenol

A specific and highly sensitive method has been developed for the determination of busulfan in plasma by gas chromatography-mass spectrometry using a deuterium-labeled busulfan (busulfan-d8) as internal standard. Plasma containing busulfan and busulfan-d8 were extracted with ethyl acetate and derivatized with 2,3,5,6-tetrafluorothiophenol prior to the monitoring of specific ions. The limit of quantification of the assay was 20 ng/ml and the calibration curve was linear over the range of 10 to 2000 ng/ml of derivatized busulfan. This method was in good agreement with the GC-MS assay using derivatization with sodium iodide and measuring diiodobutane. In addition, a pharmacokinetic study of busulfan was conducted in six children. The apparent oral clearance was 5.7+/-1.9 ml/kg/min and the volume of distribution was 1.0+/-0.4 l/kg and were similar to those previously reported in pediatric patients.

[Visual evoked potentials (VEP). Current perspectives]

INTRODUCTION

The objective of this study is to describe current tendencies in the recording and interpretation of visual evoked potentials (VEP). In the introduction we describe the history of the three main classical schools and the modern methodology which combines them, so as to study the photopic and scotopic systems together and thus be better able to determine the origin of the underlying pathology.

MATERIAL AND METHODS

We describe recording techniques using flash and chequer-board and a strategy for study of the visual pathway.

RESULTS

The application of this technique is described for pathologies in which its findings are of particular interest: Silent multiple sclerosis, Parkinson, hepatic encephalopathy, dementia and psychiatric disorders in which certain neurotransmitters play a part; visual acuity; coma and brain death; cortical blindness. A separate section deals with paediatrics, in view of its special characteristics. We call for a return to the use of this technique with great future diagnostic potential.

[Fluoxetine in the treatment of borderline personality disorder]

OBJECTIVE

This study evaluates the therapeutic effect of fluoxetine, a selective serotonin reuptake inhibitor, in borderline personality disorder.

METHOD

46 patients with borderline personality disorder according to DSM-III-R and Diagnostic Interview for Borderlines (DIB-R) criteria, were given fluoxetine 20-60 mg for seven weeks. They were evaluated each week using Brief Psychiatric Rating Scale (BPRS), Global Assessment of Functioning Scale (GAF), Hamilton Depression Rating Scale (HDRS) and a clinical Impulsivity Scale.

RESULTS

There were significant improvements in BPRS, HDRS, GAF and Impulsivity Scale from the first week of the treatment. These improvements continued until the seven week of treatment. The favourable outcome was not only due to the improvement in depression and impulsivity scores, but also to the decline of global psychopathology.

CONCLUSIONS

The data suggest that fluoxetine is an effective pharmacologic treatment for borderline personality disorder. These findings support the hypothesis of a 5-HT dysfunction in borderline personality disorder.

Pharmacokinetics of the S(+) and R(-) enantiomers of vigabatrin during chronic dosing in a patient with renal failure

AIMS

To study the pharmacokinetics of vigabatrin in a patient affected with tuberous sclerosis who developed major agitation and aggression, while receiving vigabatrin orally (1.5 g every 12 h) and in whom impaired renal function was diagnosed.

METHODS

The patient received vigabatrin (0.5 g day(-1)). A pharmacokinetic study of the S(+) and R(-) enantiomers of vigabatrin was performed before and during dialysis. Plasma concentrations were measured at 0, 1, 2, 3, 4, 6, 12, 18 and 24 h by a specific GCMS assay.

RESULTS

Before dialysis, the maximum and minimun plasma concentrations of vigabatrin at steady-state were lower for the S(+) than for the R(-) enantiomer, while the apparent oral clearance was higher for the S(+) than for the R(-) enantiomer (2.97 vs 0.48 l h(-1)). In addition, the haemodialysis clearance was similar for the two enantiomers (4.96 vs 5.15 l h(-1)).

CONCLUSIONS

Vigabatrin is an irreversible inhibitor of GABA-transaminase, effective in the treatment of drug-resistant epilepsy and reported to be eliminated unchanged by renal excretion. Although vigabatrin is known to have stereoselective kinetics, the difference in plasma dry concentrations and pharmacokinetics of the S(+) and R(-) enantiomers that we observed during long term administration at high doses in a patient with impaired renal function, has not been reported before. The question remains of the potential toxicity of the high levels of the R(-) enantiomer.

Initial results of a new procedure for treatment of malignant obstruction of the left colon

PURPOSE

This study was undertaken to analyze the results obtained in 38 unselected patients using a new and original procedure for treatment of malignant obstructions of the left colon.

METHOD

This procedure involves three phases: 1) resolution of the obstruction by means of a stent placed at the site of the tumor; 2) recovery of the general state of the patient, study of the extent of disease, and mechanical preparation of the colon; 3) regulated and final surgery (if this is not suitable, the stent may be used as definitive palliative treatment).

RESULTS

In 35 patients (92 percent), the obstruction was resolved with the stent. In 22 patients the three phases were completed, and in 13 patients the stent constituted definitive palliative treatment. Only one patient (2.6 percent) died after resection of the tumor.

CONCLUSION

This procedure offers a new, safe, and efficacious option for treatment of neoplastic colorectal obstructions.