Comparative study of extracellular recording methods for analysis of afferent sensory information: Empirical modeling, data analysis and interpretation.

BACKGROUND: Physiological studies of sensorial systems often require the acquisition and processing of data extracted from their multiple components to evaluate how the neural information changes in relation to the environment changes. In this work, a comparative study about methodological aspects of two electrophysiological approaches is described. NEW METHOD: Extracellular recordings from deep vibrissal nerves were obtained by using a customized microelectrode Utah array during passive mechanical stimulation of rat´s whiskers. These recordings were compared with those obtained with bipolar electrodes. We also propose here a simplified empirical model of the electrophysiological activity obtained from a bundle of myelinated nerve fibers. RESULTS: The peripheral activity of the vibrissal system was characterized through the temporal and spectral features obtained with both recording methods. The empirical model not only allows the correlation between anatomical structures and functional features, but also allows to predict changes in the CAPs morphology when the arrangement and the geometry of the electrodes changes. COMPARISON WITH EXISTING METHOD(S): This study compares two extracellular recording methods based on analysis techniques, empirical modeling and data processing of vibrissal sensory information. CONCLUSIONS: This comparative study reveals a close relationship between the electrophysiological techniques and the processing methods necessary to extract sensory information. This relationship is the result of maximizing the extraction of information from recordings of sensory activity.

Time-frequency analysis of neuronal populations with instantaneous resolution based on noise-assisted multivariate empirical mode decomposition.

BACKGROUND: Linear analysis has classically provided powerful tools for understanding the behavior of neural populations, but the neuron responses to real-world stimulation are nonlinear under some conditions, and many neuronal components demonstrate strong nonlinear behavior. In spite of this, temporal and frequency dynamics of neural populations to sensory stimulation have been usually analyzed with linear approaches. NEW METHOD: In this paper, we propose the use of Noise-Assisted Multivariate Empirical Mode Decomposition (NA-MEMD), a data-driven template-free algorithm, plus the Hilbert transform as a suitable tool for analyzing population oscillatory dynamics in a multi-dimensional space with instantaneous frequency (IF) resolution. RESULTS: The proposed approach was able to extract oscillatory information of neurophysiological data of deep vibrissal nerve and visual cortex multiunit recordings that were not evidenced using linear approaches with fixed bases such as the Fourier analysis. COMPARISON WITH EXISTING METHODS: Texture discrimination analysis performance was increased when Noise-Assisted Multivariate Empirical Mode plus Hilbert transform was implemented, compared to linear techniques. Cortical oscillatory population activity was analyzed with precise time-frequency resolution. Similarly, NA-MEMD provided increased time-frequency resolution of cortical oscillatory population activity. CONCLUSIONS: Noise-Assisted Multivariate Empirical Mode Decomposition plus Hilbert transform is an improved method to analyze neuronal population oscillatory dynamics overcoming linear and stationary assumptions of classical methods.

Medicamentos de diagnóstico hospitalario: oportunidad de colaboración entre farmacia hospitalaria y comunitaria / Hospital diagnosis drugs: an opportunity for collaboration between hospital and community pharmacy

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Cirugía menor en un centro de salud familiar y concordancia clínico patológica / Minor surgery in a family health center and clinicopathological concordance

INTRODUCCIÓN: Los servicios de Atención Primaria de Salud(APS) realizan Cirugía Menor(CM), evidenciándose beneficios como optimización de recursos y promoción de la actividad preventiva, diagnóstica y terapéutica. OBJETIVO: Describir la actividad de CM en un centro de APS y analizar la concordancia clínica-patológica de las lesiones...

INTRODUCTION: Primary Health Care (PHM) services perform minor surgery (MS), displaying benefits such as resource optimization and the promotion of preventive, diagnostic and therapeutic activities. OBJECTIVE: Describe the MS activity from a PHM center and analyse the clinicopathological concordance of the lesions…

The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests.

• We present the results from a litter translocation experiment along a 2800-m elevation gradient in Peruvian tropical forests. The understanding of the environmental factors controlling litter decomposition is important in the description of the carbon and nutrient cycles of tropical ecosystems, and in predicting their response to long-term increases in temperature. • Samples of litter from 15 species were transplanted across all five sites in the study, and decomposition was tracked over 448 d. • Species' type had a large influence on the decomposition rate (k), most probably through its influence on leaf quality and morphology. When samples were pooled across species and elevations, soil temperature explained 95% of the variation in the decomposition rate, but no direct relationship was observed with either soil moisture or rainfall. The sensitivity of the decay rate to temperature (κ(T)) varied seven-fold across species, between 0.024 and 0.169 °C⁻¹, with a mean value of 0.118 ± 0.009 °C⁻¹ (SE). This is equivalent to a temperature sensitivity parameter (Q10) for litter decay of 3.06 ± 0.28, higher than that frequently assumed for heterotrophic processes. • Our results suggest that the warming of approx. 0.9 °C experienced in the region in recent decades may have increased decomposition and nutrient mineralization rates by c. 10%.

Use of monoclonal antibodies for the identification of Leishmania spp. isolated from humans and wild rodents in the State of Campeche, Mexico.

The genus Leishmania includes 30 described species which infect a wide variety of mammalian hosts. The precise identification of leishmanial parasites at the species level is very important in order to determine whether an organism, causing the disease in a given area, is of the same biotype as that found in suspected mammalian reservoirs. The objectives of the present study were (1) to identify leishmanial parasites isolated from humans and wild rodents from the State of Campeche, an endemic focus of localized cutaneous leishmaniasis (LCL) in southern Mexico, using an indirect immunofluorescent assay (IFA) with monoclonal antibodies (Mabs); and (2) to determine if the parasites of the two types of hosts were of the same biotype. All the wild rodents (six Ototylomys phyllotis, eight Oryzomys melanotis, five Peromyscus yucatanicus and two Sigmodon hispidus) and 96% (24/25) of the human isolates were identified as Leishmania (L.) mexicana confirming that this specific LCL focus is a wild zoonosis. The presence of one human isolate of L. (Viannia) braziliensis in the State of Campeche, confirmed the importance of an accurate taxonomic identification at species level.

[CHRONIC DIARRHEA OF INFECTIOUS ETIOLOGY] / La Diarrea Crónica de Etiología Infecciosa.

Chronic Diarrhea syndrome is due to several causes. In LatinAmericen countries, infectious and parasitic etiology is frequent. Withinthese infections, the following has been determined: parasitic and enterobacterial agents, overpopulation of bacteria syndrome in the upper small bowel (SOBIA, abbreviation for Síndrome de Sobrepoblación Bacteriana del Intestino Delgado Alto), intestinal TBC, and AIDS. In these processes, the precipitating factor may be unique or multifactor; or there could also exist a tendency towards pathologies for these infections. There has been evidence of SOBIA cases without associated factor in Latin American countries. A study made in Peru shows SOBIA cases in 30 percent of chronic diarrhea.In chronic diarrhea cases, and even more, in those diarrheas of infectiousetiology, a complete study should be made, considering the several factorsthat generate diarrhea in a same one case, such as the mechanisms ofimmunodeficiency, neurological, endocrinemetabolic, and others associated with intestinal infections. This approach will be helpful to make a complete diagnosis and apply timely treatment.

Characterization of the tobacco glycoprotein surface binding property of heart and skeletal muscle cells. I. Modulation of the heart cell membrane TGP interaction by anti-TGP IgG.

Monolayers of L6 rat skeletal myoblast cells formed surface binding isotherms with the purified tobacco leaf glycoprotein TGP1 and the enriched cigarette tar glycoprotein TGP2. Scatchard analysis showed that the binding in the range of the limited concentrations tested was to a single class molecule and the calculated affinity constant (Kd) for TGP1 and TGP2 showed similar values (9.78 x 10(-13) M and 3.09 x 10(-13) M, respectively). The bound TGPs were almost totally displaced by excess nonradiolabeled molecules. The calculated Bmax of the L6 myoblast monolayer was 2.93 fmol for TGP1 and 0.217 fmol for TGP2 per 32.2 mm2. Guinea pig heart sarcolemma binding isotherms were also formed with radiolabeled TGP1 and TGP2. The interaction of tobacco leaf TGP1 with the heart cell membranes was irreversible because only 15-20% of the bound TGP1 was displaced by 100-fold, non-labeled molecules but the interaction of tar TGP2 with heart sarcolemma was reversible and probably saturable. The heart sarcolemma TGP2 affinity constant (Kd) was 5.88 x 10(-7) M and the Bmax, 2.45 x 10(-8) M per 12.5 micrograms sarcolemma. Pretreatment of heart sarcolemma with increasing concentrations of leaf TGP1 did not displace tar TGP2 binding but its absorption on the membrane resulted in increased TGP2 sarcolemma attachment by a complex and unexplained mechanism. Increasing concentrations of the sera of 10 of 15 guinea pigs (67%) that received mainstream emissions of tobacco smoke from a University of Kentucky cigarette smoking machine for 152 days, displaced cigarette tar TGP2 heart cell sarcolemma attachment and this inhibition was significantly different from that produced by the sera of sham smoked and of non-exposed animals (Mann-Whitney test, p = 0.0082). Staphylococcus protein A inhibited the displacement of TGP2 produced by the sera of cigarette smoke exposed guinea pigs and this observation indicated that this action was mediated by IgG molecules. The specific immunoprecipitation of a radiolabeled surface epitope of the L6 myoblast monolayers pretreated with TGP1 or TGP2 by immune IgG against TGP2 and by the IgG of an antiserum against standard TGP showed that the tobacco glycoproteins attached to a unit polypeptide of the plasma membrane of the muscle cells of approximately 76 kDa. These data support the notion that TGP molecules in cigarette smoke are absorbed systemically on smoking and may have a direct toxic effect when they attach to the surface TGP binding proteins of heart and skeletal muscle cells.

Induction of allograft tolerance in rats by an HLA class-I-derived peptide and cyclosporine A.

T cell recognition of MHC molecules initiates a cascade of events resulting in allograft rejection. CTLs damage the graft by targeting nonself-MHC class I molecules. We and others have previously shown that small synthetic peptides corresponding to regions of certain MHC class I molecules can inhibit the CTL response against MHC class I alloantigens in vitro. Here we report that rat heart allografts survived survived indefinitely when transplanted into recipients treated with a synthetic peptide corresponding to residues 75-84 of (B7.75-84) in combination with a subtherapeutic dose of cyclosporine A. Furthermore, this treatment induced long-term donor-specific tolerance that was mediated by anergic cells, indicating that such peptides may have potential as therapeutics for human organ transplantation.

Estudio clínico y etiológico de 90 casos de diarrea crónica / Clinical and ethiologic study of 90 cases of chronic diarrhea

Se realizó el presente estudio prospectivo en 90 pacientes con diarrea crónica, atendidos en la consulta externa de una clínica privada de Lima, durante los años 1990 y 1991. De acuerdo a un esquema metodológico para llegar a los factores causales y/o enfermedades generadoras de la diarrea crónica. En todos los casos se practicaron exámenes hematológicos, bioquímicos, coprocultivos, coproparasitológico, radiografías de torax y tránsito intestinal. En 11, el cultivo de contenido duodenal. Radigrafías del colon en 25 casos; proctosigmoidoscopias en 14 y endoscopía digestiva alta en 19 pacientes. Ecografías abdomnales en 12 y TAC en 2 casos. Los resultados finales mostraron como enfermedades determinantes de la diarrea crónica, por orden de frecuencia, enteroparasitosis ( 23.3 por ciento ), trastornos funcionales digestivos ( 20.0 por ciento ), sobrepoblación bacteriana intestinal ( 15.5 por ciento ), de causa no determinada ( 8.8 por ciento ), divertículos del colon ( 7.7 por ciento ), infección intestinal ( 7.7 por ciento ) comprobada y probable ( 5.5 por ciento ), intolerancia a la lactosa ( 3.3 por ciento ), diabetes mellitus ( 2.2 por ciento ); y un caso ( 1.1 por ciento ) las siguientes: linfoma intestinal, tumor de páncreas, SIDA, deformación colónica y anemia megaloblástica. Las causas de diarrea crónica son variadas y multifactoriales, y en presente estudio se comprueba la predominancia de las parasitosis intestinales, transtornos funcionales y sobrepoblación bacteriana intestinal; y en menor frecuencia otras patologías variadas

Cellular mechanisms underlying differential rejection of sequential heart and lung allografts in rats.

As the simultaneous transplantation of two or more organs into a single recipient has become increasingly common, asynchronous allograft rejection has become an important clinical problem. To investigate the cellular and molecular mechanisms underlying differential organ rejection, we developed a rat model in which heart and lung allografts were transplanted sequentially. Heterotopic heart allografts transplanted into DA recipients from PVG donors survived indefinitely if the recipients were given a short course of rabbit antirat thymocyte globulin or cyclosporine at the time of transplantation. In contrast, orthotopic left lungs transplanted under the same conditions were rejected in ATG-treated recipients and accepted in most CsA-treated recipients. These animals were then given a second organ allograft from the same strain or a third party to assess whether they exhibited donor specific tolerance and whether the acceptance or rejection of the first allograft would influence the survival of the second transplant. Animals tolerized to a heart allograft with ATG rejected an orthotopic lung transplant from the same strain as the original allograft, whereas recipients treated with CsA at the time of their heart transplant accepted a subsequent lung graft. Surprisingly, animals treated with either ATG or CsA that had rejected a lung allograft accepted a subsequent heart transplant. Using limiting dilution analysis and adoptive transfer studies, we found that some recipients had developed suppressor cells while others demonstrated anergy. We conclude that major histocompatibility complex antigens as well as other antigens are involved in the differential rejection of heart and lung allografts.

Sobrepoblación bacteriana del intestino delgado y diarrea crónica / Chronic diarrhea and small bowell bacterial overgrowth

Se estudiaron de modo prospectivo 40 pacientes adultos atendidos en el Consultorio Externo del Servicio de Gastroenterología del Hospital Cayetano Heredia (Lima), catalogados como casos de Diarrea Crónica (DC), por presentar diarrea en un período mayor de 3 semanas. Los pacientes fueron sometidos a exámenes de laboratorio: hematológicos, bioquímicos, coproparasitológicos y coprocultivos. Exámenes endoscópico digestivo y radiografías de tórax y transito intestinal. En 36 casos se practicó el cultivo del contenido duodenal mediante la técnica del Enterotest, con el objeto de determinar la existencia de Sobrepoblación Bacteriana del Intestino Delgado Alto (SOBIA); por el hallazgo de cuentas totales mayor de 10000 gérmenes por ml, y/o coliformes mayor de 1000 gérmenes por ml. Los resultados de los 36 casos mostraron 13 casos (36.1 por ciento) con diagnóstico finales únicos y en 23 casos (63.8 por ciento) éstos eran mixtos, indicando la multifactoriedad de causas de DC. Los diagnósticos principales, fueron Trastornos psicoemocionales 15 casos (41.6 por ciento), SOBIA 11 casos (30.5 por ciento), Parasitosis 6 casos (16.6 por ciento), 2 casos de Diabetes Mellitus (5.5 por ciento), un caso (2.7 por ciento) con Tuberculosis Intestinal y un caso (2.7 por ciento) Desnutrición. El hallazgo el 30.5 por ciento de Sobrepoblación Bacteriana del Intestino Delgado Alto, correspondería a una cifra mayor de la población adulta sana de Lima, y ocupa el segunda lugar en frecuencia de causas de Diarrea Crónica en el presente estudio, confirmando esta importante asociación ya antes señalada por otros investigadores. Orienta a ampliar estos estudios, más aún al tratarse de pacientes que pertenecían a sectores socio-económicos bajos y con limitadas condiciones de saneamiento ambiental

Marcadores serológicos de hepatitis viral B en pacientes drogadictos del Hospital Hermilio Valdizán / Serological markers for virus B Hepatitis in drug addict from the Hospital Hermilio Valdizán

Se realizó el estudio de detecciónn de marcadores de hepatitis B: AgsHB y anti-HBc, y del anticuerpo contra el virus de Inmunodeficiencia Humana (Anti-VIH), en 36 pacientes drogadictos no usuarios de drogas endovenosas en el Centro de Rehabilitación de Farmacodependencientes de Ñana (Hospital H. Valfizán). Los resultados mostraron positividad del AgsHB en cinco casos (13.8%), y en seis para el Anti-HBc (16.6%), porcentaje altos comparándolos con la población general adulta de la Costa peruana. El Anti-VIH fue negativo en los 36 casos. De acuerdo a la información obtenida, las vías de transmisión serían variadas, resaltando ciertas características de su vida sexual. El estudio de 36 casos, frente a los 44 egresos de ese año en dicho centro, es representativo; sin embargo, se requiere ampliar este estudio para determinar la prevalencia de la infección en este tipo de drogadictos, que constituye la forma más frecuente en el país, lo cual contribuirá para recomendar medidad de control y prevención

Famotidina en el tratamiento de la úlcera péptica gástrica / Famotidine in the treatment of gastric peptic ulcer

En el presente estudio multicéntrico abierto, se evaluó la eficacia del antagonista H2 FAMOTIDINA MSD en promover la cicatrización de la úlcera péptica gástrica, así como su tolerancia y seguridad. Veintiocho pacientes con úlcera péptica gástrica, demostrada por endoscopía e histología, recibieron famotidina 40 mg (una tableta) noche, hasta por ocho semanas. El tratamiento se suspendió a la cuarta semana en caso de evidenciarse cicatrización. Todos los pacientes fueron evaluables para eficacia y seguridad. Se consiguió cicatrización de la úlcera en veintidos de ellos (78.6%), requiriéndose sólo cuatro semanas de tratamiento en quince (53.6%). El 25% de los pacientes se tornó asintomático a las 72 horas y el 60% al finalizar la primera semana. La droga fue bien tolerada y no se registraron reacciones adversas clínicas, ni de laboratorio. Los resultados del presente estudio utilizando famotidina 40 mg. noche, muestran que esta es una terapia eficaz, bien tolerada y segura en la mayoría de pacientes con úlcera péptica gástrica

Diarrea Crónica Asociada a infección por Isospora Belli. Reporte de un caso. / Chronic Diarrhea associated with Isospora Belli infection. Case Report.

La Isospora Belli es un porotozoario que pertenece a la clase esporozoa, infecta las porciones altas del intestino delgado y puede generar manifestaciones clínicas de grado variable . Se presenta un caso de diarrea crónica, con baja de peso, vómitos y deshidratación. Se halla ooquistes y macromegacito de I. Belli en las heces y en la biopsia duodenal, respectivamente. Con el uso de trimetropín-sulfametoxazol, se obtuvo una excelente respuesta terapéutica. Se revisa la información bibliográfica relacionada a esta parasitosis, señalándose su poca frecuencia en nuestro país.