Relationship between pest grasshopper densities and climate variables in the southern Pampas of Argentina.

Grasshoppers are one of the most predominant insects in the grasslands of the southern Pampas. In this region, Dichroplus elongatus, Dichroplus maculipennis, Dichroplus pratensis and Borellia bruneri are the most abundant species and have the greatest economic importance. This study aimed to assess the relationship between temporal changes in the density of these species and climate variables associated with temperature and rainfall over an 11-year study period., We monitored 22 sites in different areas of Laprida county from 2005 to 2016. A total of 25 grasshopper species were collected. The most abundant species were D. maculipennis and B. bruneri which reached the highest densities from 2008-2009 to 2010-2011. The rainfall accumulated from September (RAS) to the sampling date and the number of rainy days (RD) largely explained the density variation of B. bruneri. Besides RD and RAS, winter rainfall, rainfall accumulated from October to the sampling date, and thermal amplitude of October (TAO) influenced the density of D. maculipennis. Our results indicated that seasons with less rainfall and fewer RD favored these two species' abundance. We identified that the RD and TAO contributed significantly to variations in the density of D. elongatus. In contrast to the other two species, we recorded D. elongatus in seasons with high rainfall and high RD. A better understanding of the climate influence on the life cycle of these economically important insects may identify key factors in their population dynamics which in turn may improve management options.

Pastoralism in the drylands of Latin America: Argentina, Chile, Mexico and Peru. / Pastoralismo en zonas áridas de Latinoamérica: Argentina, Chile, México y Perú.

This article discusses various aspects of pastoralism in the Latin American countries with the largest dryland areas. The topics covered include: social, economic and institutional issues; grasslands and their carrying capacity; production systems and productivity rates; competition for forage resources between domestic livestock and wildlife; and the health status of livestock and wildlife. Most grasslands exhibit some degree of degradation. The percentage of offspring reaching weaning age is low: 47-66% of calves and 40-80% of lambs. Some pastoralists adopt patterns of transhumance. In the main, pastoralists experience a high poverty rate and have poor access to social services. For many pastoralists, wildlife is a source of food and by-products. Argentina, Chile, Mexico and Peru have animal health control agencies, are members of the World Organisation for Animal Health (OIE) and have signed the United Nations Convention to Combat Desertification. Pastoral systems subsist mainly on income unrelated to pastoral farming. The OIE recognises all four countries as free from infection with peste des petits ruminants virus, and from rinderpest and African horse sickness. It is difficult to predict the future of pastoralism in Latin America because the situation differs from country to country. For instance, pastoralism is more important in Peru than in Argentina, where it is a more marginal activity. In the future, lack of promotion and protection policies could lead to a decline in pastoralism or to an adverse environmental impact on drylands.

Les auteurs abordent les particularités du pastoralisme dans les quatre pays d'Amérique latine dotés des plus vastes étendues de terres arides du souscontinent ; ils examinent notamment les aspects sociaux, économiques et institutionnels du pastoralisme, les pâtures et leur capacité de charge, les systèmes de production et les indices de productivité, la concurrence entre le bétail et les animaux sauvages pour le prélèvement de fourrage et le statut sanitaire respectif des animaux d'élevage et de la faune sauvage. Les prairies dédiées au pastoralisme présentent dans leur majorité un certain degré de dégradation. Le taux de survie au sevrage fluctue entre 47 % et 66 % pour les veaux et entre 40 % et 80 % pour les agneaux. Certains pasteurs adoptent des schémas de transhumance. Les populations pastorales se caractérisent par un niveau élevé de pauvreté et un accès très limité aux services sociaux. Pour de nombreux pasteurs, la faune sauvage constitue une ressource alimentaire directe mais elle fournit aussi des produits dérivés. En Argentine, au Chili, au Mexique et au Pérou, des services gouvernementaux sont chargés du contrôle de la santé animale. Ces pays sont Membres de l'Organisation mondiale de la santé animale (OIE) et signataires de la Convention des Nations Unies sur la lutte contre la désertification. Les systèmes pastoraux subsistent essentiellement grâce à des revenus autres que ceux issus de la production. Ces territoires ont été reconnus par l'OIE comme étant indemnes d'infection par les virus de la peste des petits ruminants, de la peste bovine et de la peste équine. Il est difficile de prédire l'avenir du pastoralisme en Amérique latine, en raison de la diversité des situations rencontrées d'un pays à l'autre. Par exemple, l'activité pastorale est plus importante au Pérou qu'en Argentine où elle a un caractère marginal. L'absence de politiques de promotion et de protection spécifiques pourrait se traduire à l'avenir par un déclin du pastoralisme ou par un impact écologique négatif pour ces zones arides.

Se abordan matices del pastoralismo relativos a los países con mayor extensión de zonas áridas de Latinoamérica, concretamente, los aspectos sociales, económicos e institucionales, los pastizales y su receptividad, los sistemas de producción e índices de productividad, la competencia entre ganado doméstico y fauna silvestre por el recurso forrajero, y el estatus sanitario del ganado y de los animales silvestres. La mayor parte de los pastizales presenta algún grado de deterioro. El porcentaje de crías que llega al destete fluctúa entre el 47% y el 66% en bovinos y entre el 40% y el 80% en ovinos. Algunos pastoralistas adoptan patrones de trashumancia. Los pastores se caracterizan básicamente por un índice alto de pobreza y un escaso acceso a los servicios sociales. La fauna es un recurso alimentario y una fuente de subproductos para numerosos pastores. Argentina, Chile, México y Perú cuentan con organismos destinados al control de la sanidad animal, son miembros de la OIE y han suscrito la Convención de las Naciones Unidas de Lucha contra la Desertificación. Los sistemas pastoriles subsisten principalmente a partir de ingresos ajenos a su producción. La OIE reconoce a estos territorios como libres de infección por peste de los pequeños rumiantes, por peste bovina y por peste equina. Es difícil predecir el futuro del pastoralismo en Latinoamérica debido a las diferentes situaciones de cada país. Así, por ejemplo, en Perú, esta práctica tiene mayor importancia que en Argentina, donde es más marginal. La carencia de políticas de promoción y protección podría conducir en el futuro a una disminución de la actividad o a un impacto ecológico negativo en las zonas áridas.

Osteosarcoma multicéntrico sincrónico con múltiples tumores primarios o enfermedad metastásica: Reporte de un caso y revisión de la literatura / Synchronous multicentric osteosarcoma: with multiple primary tumors or metastatic disease. Report of one case and literature review

El osteosarcoma multicéntrico sincrónico, es un tumor cuya presentación ocurre en dos o más sitios sin la aparición de metástasis pulmonares. Tiene una incidencia de 1 al 3% de todos los osteosarcomas y sólo se han documentado menos de 100 casos en la literatura. En nuestro caso, presentamos a un paciente de seis años seis meses de edad con una tumoración dolorosa en muslo izquierdo, diagnosticado mediante toma de biopsia incisional, la cual reportó osteosarcoma convencional de alto grado en fémur distal izquierdo, con una lesión en la extremidad contralateral en fémur distal y tibia proximal, sin respuesta favorable a la quimioterapia. Se detectaron metástasis pulmonares y cerebrales, por lo que se decidió en forma multidisciplinaria brindar manejo paliativo de la enfermedad. Aun años después de su descripción continúa el debate sobre si esta condición realmente corresponde a una variante primaria o bien a una manifestación de la enfermedad metastásica.

Synchronous multicentric osteosarcoma, is a tumor with presentation in two or more sites without the appearance of lung metastasis. The incidence is 1 to 3% of all osteosarcomas and only less than 100 cases have been documented in the literature. In our case, we are presenting a six and a half year old patient with a painful tumor in the left thigh diagnosed with an incisional biopsy that reported a high grade conventional osteosarcoma in the left distal femur, a lesion in the contralateral limb in distal femur and proximal tibia, with no favorable response to chemotherapy. Lung and brain metastases were detected; therefore, we decided to give multidisciplinary palliative care for the disease. Years after its description there is still debate whether this condition really corresponds to a primary variable or to a manifestation of the metastatic disease.

[Synchronous multicentric osteosarcoma: with multiple primary tumors or metastatic disease. Report of one case and literature review]. / Osteosarcoma multicéntrico sincrónico con múltiples tumores primarios o enfermedad metastásica. Reporte de un caso y revisión de la literature.

Synchronous multicentric osteosarcoma, is a tumor with presentation in two or more sites without the appearance of lung metastasis. The incidence is 1 to 3% of all osteosarcomas and only less than 100 cases have been documented in the literature. In our case, we are presenting a six and a half year old patient with a painful tumor in the left thigh diagnosed with an incisional biopsy that reported a high grade conventional osteosarcoma in the left distal femur, a lesion in the contralateral limb in distal femur and proximal tibia, with no favorable response to chemotherapy. Lung and brain metastases were detected; therefore, we decided to give multidisciplinary palliative care for the disease. Years after its description there is still debate whether this condition really corresponds to a primary variable or to a manifestation of the metastatic disease.

Impacto de la resistencia a la meticilina sobre la mortalidad y vigilancia de la sensibilidad a la vancomicina en bacteriemias causadas por Staphylococcus aureus / Impact of methicillin resistance on mortality and surveillance of vancomycin susceptibility in bacteremias caused by Staphylococcus aureus

Staphylococcus aureus es uno de los principales patógenos nosocomiales y produce una alta morbimortalidad en numerosos hospitales del mundo. Además, la incidencia de bacteriemias por este microorganismo ha aumentado significativamente en las últimas décadas. Los objetivos del presente trabajo fueron identificar los factores de riesgo que favorecen la aparición de resistencia a la meticilina en aislamientos de S. aureus y los factores que afectan la mortalidad por bacteriemias asociadas a este patógeno, así como evaluar la sensibilidad a la vancomicina de las cepas resistentes a la meticilina. Se estudiaron 39 aislamientos de S. aureus provenientes de hemocultivos de pacientes internados con bacteriemia en la Nueva Clínica Chacabuco de Tandil (Pcia. de Buenos Aires, Argentina) en el período 01/2006-12/2008. La mortalidad global fue del 51,3% y estuvo significativamente asociada con la resistencia a la meticilina (OR: 4,20; IC95%: 1,08-16,32; p: 0,05); aunque dicho factor no fue un predictor independiente de mortalidad. La cirugía previa (OR: 17,23; IC95%: 1,80-164,60) y la estancia previa en la unidad de cuidados intensivos (OR: 21,12; IC95%: 2,33-191,30) fueron predictores independientes de la resistencia a la meticilina y la asistencia respiratoria mecánica (OR: 15,99; IC: 3,24-78,86) fue un predictor independiente de la mortalidad. No se detectaron cepas con sensibilidad disminuida a la vancomicina. Todos los aislamientos estudiados fueron sensibles in vitro a la vancomicina, con una CIM50 y una CIM90 de 0,5 μg/ml.

Staphylococcus aureus is a major nosocomial pathogen that causes severe morbidity and mortality in many hospitals worldwide. Besides, the incidence of S. aureus bacteremia has significantly increased over the past decades. The aims of this study were to detect the risk factors for methicillin resistance and mortality and to evaluate vancomycin susceptibility in methicillin-resistant isolates. Thus, 39 S. aureus isolates from blood cultures of hospitalized patients with bacteremia were studied in Nueva Clínica Chacabuco Tandil, Buenos Aires, Argentina during 01/2006-12/2008. The overall mortality was 51.3%, which was significantly associated with methicillin resistance (OR: 4.20, IC95%: 1.08-16.32, p: 0.05), even though it was not an independent mortality predictor as it was the mechanical ventilation (OR: 15.99, IC95%: 3.24 - 78.86). Previous surgery (OR: 17.23, IC95%: 1.80-164.60) and hospitalization in intensive care units (OR: 21.12, IC95%: 2.33-191.30) were independent predictors of meticillin-resistance. No isolates were found with reduced vancomycin susceptibility. All the studied isolates were in vitro susceptible to vancomycin with a MIC50 and MIC90 of 0.5 μg/ml.

[Impact of methicillin resistance on mortality and surveillance of vancomycin susceptibility in bacteremias caused by Staphylococcus aureus]. / Impacto de la resistencia a la meticilina sobre la mortalidad y vigilancia de la sensibilidad a la vancomicina en bacteriemias causadas por Staphylococcus aureus.

Staphylococcus aureus is a major nosocomial pathogen that causes severe morbidity and mortality in many hospitals worldwide. Besides, the incidence of S. aureus bacteremia has significantly increased over the past decades. The aims of this study were to detect the risk factors for methicillin resistance and mortality and to evaluate vancomycin susceptibility in methicillin-resistant isolates. Thus, 39 S. aureus isolates from blood cultures of hospitalized patients with bacteremia were studied in Nueva Clínica Chacabuco Tandil, Buenos Aires, Argentina during 01/2006-12/2008. The overall mortality was 51.3%, which was significantly associated with methicillin resistance (OR: 4.20, IC95%: 1.08-16.32, p: 0.05), even though it was not an independent mortality predictor as it was the mechanical ventilation (OR: 15.99, IC95%: 3.24 - 78.86). Previous surgery (OR: 17.23, IC95%: 1.80-164.60) and hospitalization in intensive care units (OR: 21.12, IC95%: 2.33-191.30) were independent predictors of meticillin-resistance. No isolates were found with reduced vancomycin susceptibility. All the studied isolates were in vitro susceptible to vancomycin with a MIC50 and MIC90 of 0.5 µg/ml.

Modulation of established murine collagen-induced arthritis by a single inoculation of short-term lipopolysaccharide-stimulated dendritic cells.

BACKGROUND: The use of regulatory or immature dendritic cells (DCs) as tools for modulating experimental rheumatoid arthritis is very recent. Tumour necrosis factor (TNF)-stimulated DCs have been shown to restore tolerance in experimental autoimmune encephalomyelitis and collagen-induced arthritis (CIA). OBJECTIVE: We investigated the capacity of short-term lipopolysaccharide (LPS)-stimulated DCs pulsed with type II collagen (CII) to induce tolerance against established CIA. METHODS: Bone marrow-derived DCs were generated in the presence of granulocyte monocyte colony-stimulating factor (GM-CSF). After CIA induction, mice were injected at day 35 with a single dose of 4- or 24-h LPS-stimulated DCs that had been loaded with CII (4hLPS/CII/DCs or 24hLPS/CII/DCs). Arthritis progression was monitored by clinical and histological evaluations. RESULTS: Flow cytometry of 4hLPS/CII/DCs showed intermediate CD40 and CD86 expression, lower than that of 24hLPS/CII/DCs (fully mature) and higher than that of CII/DCs (immature). A functional assay showed that 4hLPS/CII/DCs display increased endocytosis ability with respect to 24hLPS/CII/DCs, indicating a semimature state. The single inoculation of 4hLPS/CII/DCs in mice with established CIA reduced disease severity significantly over time. Histological evaluation of mice treated with 4hLPS/CII/DCs revealed diminished inflammatory synovitis, cartilage damage and fibrosis. Co-cultures of DCs with splenocytes from CIA mice showed that collagen-specific interferon (IFN)gamma production was dramatically inhibited by 4hLPS/CII/DCs. 4hLPS/CII/DCs were high IL10 producers, which could explain the inhibition of arthritis progression in mice receiving this treatment because neither antibodies nor regulatory CD4+CD25+Foxp3+ T lymphocytes were demonstrated to be involved. CONCLUSION: Short-term LPS-modulated DCs inoculation interferes with CIA progression when loaded with CII.

Histological characteristics and steroid concentration of ovarian follicles at different stages of development in pregnant and non-pregnant dairy cows.

The aim of the study was to investigate the histological characteristics and steroid concentrations in follicular fluid of different populations of follicles at different stages of development, during pregnancy and the oestrous cycle in cows. Follicles from ovaries collected at a slaughterhouse were allocated into three size categories (small, 2-5.9 mm; medium, 6-13.9 mm; and large, 14-20 mm) in pregnant and non-pregnant cows. Slices were stained with HE and PAS for histological analysis. Follicular fluid was pooled according to size and pregnancy status and estradiol, testosterone and progesterone concentrations in follicular fluid were determined by RIA. Characteristics of healthy follicles did not differ, regardless of follicle size or pregnancy status. Total histological atresia was significantly higher in pregnant cows than in non-pregnant cows (p < 0.05). Estradiol increased and testosterone decreased significantly, while follicles increased in size, in both non-pregnant and pregnant cows (p < 0.05). Nonpregnant cows had the highest estradiol values in follicles of all sizes. Medium and large follicles from pregnant cows showed the lowest testosterone concentration (p < 0.05). Progesterone levels increased with follicle size only in non-pregnant animals. In large follicles, progesterone concentration was significantly higher in non-pregnant cows than in pregnant cows (p < 0.05). Considering steroid concentration and histological findings, most large follicles might be atretic during pregnancy in cattle.

First Report of Fusarium Crown and Root Rot Caused by Fusarium solani on St. John's-Wort in Argentina.

Since 2001, 15 to18% of commercial plantings of the medicinal plant St. John's-wort (Hypericum perforatum L.) in Buenos Aires Province, Argentina were affected by a new disease. Disease symptoms of crown and root rot, wilting, chlorosis, and necrosis of the leaves appeared in circular-to-irregular shaped sectors of 12- to 14-month-old plants. Symptoms began with foliage turning yellow followed by an irregular, brown necrosis of the leaf margins. Lesions coalesced to form large necrotic areas causing a severe defoliation of the basal and upper leaves. A soft rot affected the crown and roots causing a complete maceration of these tissues. Infected plants broke off easily because the crown region and the roots were destroyed. As the disease developed, a dark brown discoloration girdled the stems that progressed above the soil line to the apex. The infected stems became dry and breakable. Finally, the affected plants died. Segments (1 cm long) were taken from roots and rotted crowns of diseased plants, dipped in 70% ethanol, surface sterilized with NaOCl (1%) for 1 min, and rinsed in sterile water. Each segment was blotted dry and placed on potato dextrose agar. Plates were incubated in the dark at 26°C for 4 to 7 days. The predominate fungus isolated from the diseased tissue was identified as Fusarium solani (Mart.) Sacc. (1). Koch's postulates were completed by dipping the roots of seedlings in a 2 × 106 conidia per ml suspension of a single spore isolate for 45 min. Plants were repotted (20 inoculated and 10 controls) in a sterilized soil mix (soil/sand 2:1) and held in the greenhouse at 23 to 26°C. Characteristic symptoms identical to the original developed on 90% of inoculated plants within 2 weeks after inoculation. Symptoms included wilt and collapse, crown and root rot, and death of the plants. The fungus was recovered from symptomatic tissues. Control plants dipped into distilled water remained healthy. The experiment was repeated, and the results were identical to the first inoculations. To our knowledge, this is the first report of St. John's-wort as a susceptible host of F. solani. Reference: (1) P. E. Nelson et al. Fusarium species. An Illustrated Manual for Identification. Pennsylvania State University Press, University Park, 1983.

Experiencia biliar endoscópica en la "Clínica Nueva" / Endoscopic biliary experience at Clínica Nueva

Se realiza la revision de los procedimientos endoscopicos realizados en la Clinica Nueva de Bogota entre septiembre de 1995 y febrero de 2000; se informa la incidencia por sexo asi: mujeres 60.8 por ciento, hombres 39.2 por ciento; los rangos de las edades están entre 24 y 93 años con promedio de 62 años; los tiempos endoscopicos que se requirieron para la realizacion de los procedimientos fueron, 1 tiempo 86.67 por ciento, 2 tiempos 11.25 por ciento y 3 tiempos 2.08 por ciento.Se cuantifican los diagnosticos, los hallazgos en los pacientes operados y no operados, la incidencia de los diferentes tipos de tumores y de los procedimientos, ya sea solo con angiografia diagnostica, esfinterotomia endoscopica, extraccion de cálculos o procedimientos de drenaje. Por ultimo, se hace una comparacion entre nuestros resultados ( sangrado 1.25 por ciento, pancreatitis 2.9 por ciento, impactacion de canastilla 0.4 por ciento, perforacion 0.4 por ciento, mortalidad asociada 0.8 por ciento) y los de la literatura mundial.

Canine transmissible venereal tumour: a morphological and immunohistochemical study of 11 tumours in growth phase and during regression after chemotherapy.

Eleven dogs with canine transmissible venereal tumour (CTVT) were given vincristine sulphate chemotherapy to induce tumour regression. Biopsy specimens were collected from tumours during the growth phase, before chemotherapy, and again from the same dogs during the regression induced by chemotherapy. Laboratory assessment included cytology, histology, the number of tumour cells in relation to the number of intratumoral leucocytes, proliferative and apoptotic fractions of tumour cells, intratumoral vessel density, and fibrosis. The results revealed that during regression, tumour cell proliferation ceased, apoptosis increased, leucocytes increased (with increased proportion of T lymphocytes), tumour parenchyma collapsed around intratumoral vessels, and fibrosis increased. These results, which were similar to findings in dogs with spontaneous regression of CTVT, suggest that tumour immunity plays a role in tumour regression after modest chemotherapy.

Constraints on CD4 recovery postchemotherapy in adults: thymic insufficiency and apoptotic decline of expanded peripheral CD4 cells.

To examine the mechanisms of CD4 reconstitution in an adult population, lymphocyte repopulation was assessed following dose-intense chemotherapy in 25 breast cancer patients, ages 33 to 69 years. Chemotherapy resulted in a greater than 60% reduction in total CD4 T cells and, in particular, a greater than 90% loss of the CD45RA+ CD4 cells. CD4 recovery was protracted, achieving less than 50% of pretreatment levels after 12 to 14 months. Two facets of the CD4 recovery were notable. First, generation of CD45RA+ CD4 cells played only a minor role in the first year, suggesting that thymic production was not the main route of CD4 regeneration. Indeed, recovery of CD45RA+ CD4 cell levels remained limited in half of the patients even after 2 years. Second, expansion of the mature peripheral CD4 cells (CD45RO+) remaining after chemotherapy was the main source of early CD4 repopulation, peaking at 3 to 6 months postchemotherapy. This expansion was limited in duration, however, and was followed by a secondary decline, such that the total CD45RO+ CD4 levels at 9 to 12 months were lower than at 6 months. When stimulated by mitogens, an increased susceptibility to apoptosis was observed in postchemotherapy CD4 cells as compared with those from normal donors. The elevated expression of markers such as HLA-DR during chemotherapy and for several months postchemotherapy is consistent with the presence of an activated T-cell population. CD4 apoptotic frequency correlated with the frequency of HLA-DR expression on T cells. Thus, CD4 recovery is constrained in adults by a limited thymic regenerative capacity and by an increased susceptibility to apoptosis within the expanding peripheral CD4 population.

Acute graft-versus-host reaction can be aborted by blockade of costimulatory molecules.

Injection of parental lymphocytes into an unirradiated adult F1 host results in an acute GVH reaction characterized by immune deficiency, attack on host lymphohematopoietic tissues, and repopulation with donor-derived cells. All of these events result from the initial activation of donor lymphocytes by host alloantigens. Interaction of pairs of host and donor costimulatory molecules, in particular CD28/CTLA4 and B7-1/B7-2, play a crucial role in this initial activation of donor T cells. We demonstrate here that in vivo treatment of the host with high doses of CTLA4-Ig solely during the initial period of donor alloactivation can completely abort the subsequent development of GVH reaction. Although donor T cells are retained, CTLA4-Ig treatment reduces the initial endogenous cytokine production and arrests the subsequent expansion of donor T cells, the differentiation of anti-host effectors, and the development of severe immune deficiency. This result is consistent with the establishment of host-specific tolerance in the donor population, while maintaining host immune competence.

Analgesia y hemostasia postartroscopia de rodilla con bupivacaina mas epinefrina intraarticular

El presente estudio tiene el objeto de recomendar el uso de bupivacina más epinefrina intraarticular al término de la cirugía artroscopica de rodilla como analgésico y antihemorrágico. Para poder cumplir con lo expuesto y que los resultados contribuyan directamente en beneficio del paciente, el estudio se ha dividido en dos etapas, la primera un estudio piloto descriptivo realizado en 53 pacientes que acudieron a los hospitales Carlos Andrade Marín y de las Fuerzas armadas de Quito en un período de tres meses, los casos fueron escogidos de acuerdo a criterios de inclusión y exclusión. la segunda etapa un estudio randomizado, a doble ciego en 24 pacientes cuyo n fue determinado en base a datos del estudio piloto inicial, en los mismos hospitales. La primera etapa se realizó en tres meses siendo una decisión operativa, así como se necesitó dos meses para la segunda etapa. En el estudio descriptivo se evaluó el dolor en relación al movimiento articular y a los rangos de movilidad alcanzados activamente. El sangrado existente a través del choque rotuliano y la cantidad de sangre obtenida por punción articular. En la segunda etapa para que le estudio del dolor y del sangrado tenga una valoración cuantitativa se utilizó además la escala analógica visual del dolor, así como, la valoración de hemoglobina y proteínas en el líquido obtenido por punción. Entre la primera y segunda etapa de la investigación existe bastante militud en la población estudiada; así tenemos que los pacientes con patología de rodilla que fueron sometidos a artroscopia se hallan entre los 20 y 49 años de edad; en la primera etapa con 44 de 46 pacientes que representaba el 95 por ciento, en la segunda etapa con 22 de 24 pacientes que representa el 91,7 por ciento. El diagnostico preoperatorio más frecuente fueron las meniscopatias: En la primera etapa con 29 pacientes que representael 63 por ciento, en la segunda etapa con 15 pacientes que representa el 62.2 por ciento. El tiempo de intervención quirúrgica en las dos etapas tiene una medida de 44.4 minutos. El mayor porcentaje de diagnósticos definitivos de las patologías en el transoperatorio fueron las meniscopatías: en la primera etapa con 24 pacientes que equivalen al 52.2 por ciento y en la segunda etapa con 12 pacientes que equivalen al 50 por ciento Las intervenciones más frecuentes por lo tanto, fueron las menisctomias, en la primera etapa con 18 procedimientos que represe...

T-cell regeneration after bone marrow transplantation: differential CD45 isoform expression on thymic-derived versus thymic-independent progeny.

To study the source of regenerated T cells after bone marrow transplantation (BMT), lethally irradiated thymectomized and thymus-bearing C57BL/6 (Thy 1.2+) mice were injected with syngeneic T-cell depleted bone marrow (TCD BM) cells and graded numbers of congenic B6/Thy 1.1+ lymph node (LN) cells. LN cell expansion was the predominant source for T-cell regeneration in thymectomized hosts but was minimal in thymus-bearing hosts. Analysis of T-cell receptor (TCR) expression on LN progeny showed a diverse V beta repertoire. Therefore, peripheral T-cell progenitors exist within V beta families, but expansion of these progenitors after BMT is downregulated in the presence of a functional thymus. CD4+ cells derived from BM versus LN in thymus-bearing hosts displayed differential CD44 and CD45 isoform expression. BM-derived cells were primarily CD45RB+CD44lo and LN derived cells were nearly exclusively CD45RB- CD44hi. In thymectomized hosts, BM, host, and LN CD4+ progeny were CD45RB- CD44hi. We conclude that T-cell regeneration via peripheral T-cell progenitors predominates in hosts lacking thymic function and gives rise to T cells that display a "memory" phenotype. In contrast, the ability to generate sizable populations of "naive" type T cells after BMT appears limited to the prethymic progenitor pool and could serve as a marker for thymic regenerative capacity.

Expression of a MHC class II transgene determines both superantigenicity and susceptibility to mammary tumor virus infection.

Milk-borne mouse mammary tumor virus (MMTV) is a type B retrovirus that induces mammary carcinoma. Infectious MMTV, as well as genomically integrated mouse mammary proviruses, encode superantigens that are recognized by T cells that express appropriate T cell receptor V beta products. To determine the relationship between the superantigenic property of milk-borne MMTV and its in vivo infectivity, mice which were either positive or negative for expression of a transgene-encoded E alpha E beta class II major histocompatibility complex (MHC) product were exposed to milk borne C3H MMTV. Superantigen-mediated deletion of V beta 14-expressing T cells occurred only in E alpha transgene-positive mice, indicating that the deletion was E alpha E beta dependent. When mice were analyzed for viral infection by assaying viral p28 in the milk of recipient females, significant p28 levels were found only in E alpha E beta transgene-positive mice. Similarly, the presence of C3H MMTV LTR mRNA in mammary glands, as detected by PCR, paralleled p28 levels. These findings indicate that E alpha expression or the E alpha-dependent T cell response to viral superantigen is causally related to susceptibility to MMTV infection, and that lack of a permissive class II product can protect mice from virus infection.

[Ventricular activation time of the fetal heart]. / El tiempo de activación ventricular del corazón fetal.

The prenatal risk determined by smoking pregnant woman was studied by a fetal electrocardiogram at different gestational ages. There were 28 low risk pregnancy women selected and qualified by means of an 80% completion of the Perechtl optimal criterion, 13 which smoked more than 5 cigarettes daily and 15 (53%) non-smokers. A new computerized technique was defined and applied for recording a continuous fetal electrocardiogram for long periods of time. Measurements of the QRS complex, inscription time of the intrinsecoid deflection (TIDI) and intrinsecoid deflection (DI) lengths were taken and compared with the gestational age. It was observed that there is a relationship of statistical significance (p less than 0.005) between the gestational age and the QRS length in the nonsmoking women. This relationship was smaller in the smoking group and furthermore it was negative when comparing the gestational age with the TIDI. There was no statistical difference in the weight of the child at birth in both groups, nevertheless the fetal electrocardiogram is useful in determining the development of the ventricular mass. In the smoking group the lack of relationship between the QRS length and the gestational age is probably owing to the retarded cardiac development and expressed ahead of all other features in fetal growth including low weight at birth.