Assessment of ß-Cell Replication in Isolated Rat Islets of Langerhans.

Pancreatic ß-cells in the islets of Langerhans secrete insulin in response to the rise in glucose levels following food intake. The hypoglycemic action of insulin applies a strong evolutionary brake on ß-cell division. However, under some conditions ß-cells can be stimulated to enter cell cycle progression and divide, for example following exposure to increased glucose levels or during pregnancy. Here, a protocol is described for the isolation of rat adult islets of Langerhans, followed by culture of intact islets in Matrigel and measurement of ß-cell replication by the incorporation of ethynyldeoxyuridine (EdU). EdU positive cells are revealed by a click reaction, nuclei are visualized using a DNA-binding fluorophore (Hoechst 33342), and ß-cells are identified using immunofluorescence detection.

Chemical characterization, antioxidant, genotoxic and in vitro cytotoxic activity assessment of Juniperus communis var. saxatilis.

Chemical composition and antioxidative, genotoxic and cytotoxic potential of essential oil (EO) and post-distillation waste (PDW) of Serbian Juniperus communis L. var. saxatilis Pall. was studied in human lung carcinoma (A549) and normal lung fibroblast (MRC-5) cells. GC-MS analysis identified 93.95% of total EO content and determined α-pinen as a dominant component (23.61%). LC-MS/MS analysis of PDW pointed at rutin (12.2 mg g-1) and quinic acid (11.1 mg g-1) as the most abundant. Antioxidativity of PDW was strong in DPPH (IC50 was 5.27 µg mL-1), and moderate in TBA and FRAP assays. Both substances were more cytotoxic to A549 than to MRC-5 cells. Obtained IC50 values were 69.4 µg mL-1 and 120 µg mL-1 for EO, and 1.27 mg mL-1 and 2.86 mg mL-1 for PDW, respectively. PDW was genotoxic (0.3 mg mL-1 and 1 mg mL-1 in A549 and MRC-5 cells, respectively) and induced apoptosis and arrested cell cycle in G2/M phase in A549 cells (0.3 mg mL-1). In mixtures with doxorubicin cytotoxicity of EO and PDW increased, and combination index values (0.12-0.18) revealed clear synergistic effect, stronger in cancer cells. This indicates that J. communis var. saxatilis could decrease the chemotherapeutic doses of doxorubicin, potentially reducing its side effects.

Chronic interleukin-1 exposure drives haematopoietic stem cells towards precocious myeloid differentiation at the expense of self-renewal.

Haematopoietic stem cells (HSCs) maintain lifelong blood production and increase blood cell numbers in response to chronic and acute injury. However, the mechanism(s) by which inflammatory insults are communicated to HSCs and their consequences for HSC activity remain largely unknown. Here, we demonstrate that interleukin-1 (IL-1), which functions as a key pro-inflammatory 'emergency' signal, directly accelerates cell division and myeloid differentiation of HSCs through precocious activation of a PU.1-dependent gene program. Although this effect is essential for rapid myeloid recovery following acute injury to the bone marrow, chronic IL-1 exposure restricts HSC lineage output, severely erodes HSC self-renewal capacity, and primes IL-1-exposed HSCs to fail massive replicative challenges such as transplantation. Importantly, these damaging effects are transient and fully reversible on IL-1 withdrawal. Our results identify a critical regulatory circuit that tailors HSC responses to acute needs, and is likely to underlie deregulated blood homeostasis in chronic inflammation conditions.

Delimitación de fronteras como estrategia de control social: el caso de la violencia homicida en Medellín, Colombia / Marking bourdaries as a strategy of social control: the case of homicidal violence in Medellin, Colombia

En el marco de un estudio realizado entre 2003 y 2011 para comprender escenarios de violencia homicida a partir de la percepción del hecho violento y su contexto, se reflexiona sobre el sentido de las "fronteras invisibles" en barrios de Medellín (Colombia). Desde un enfoque cualitativo que combina revisión documental y entrevistas, se analiza la experiencia vivida por ocho participantes. Entre los principales resultados se destaca que el control barrial es ejercido por distintos actores; que las fronteras no son visibles para el común de las personas, sino que son demarcaciones en las que son reclutadas y controladas, y que consolidan estrategias para recaudar recursos económicos de forma ilegal y regular las actividades culturales y sociales de los habitantes, lo cual repercute en la dinámica y los imaginarios sociales. De este modo, se controlan los territorios, las amistades y los afectos de víctimas jóvenes -que no se vinculan a grupos ilegales y/o no tienen "información"- y de adultos mayores indefensos.

As part of a research study undertaken in the period 2003-2011 to understand situations of homicidal violence based in perceptions regarding the act of violence and the surrounding context, we reflect on the meaning of "invisible bourdaries" in the neighborhoods of Medellin (Colombia). Using a qualitative approach that combines documentary sources and interviews, the experiences of 8 participants are analyzed. In the primary results we can see how control over neighborhoods is exercised by different actors through bourdaries not visible to ordinary people. Nevertheless, around these lines people are recruited and controlled and strategies to illegally generate economic resources and to regulate the cultural and social activities of inhabitants are consolidated, thus affecting the social dynamics and imaginary of the neighborhood. In this way, the territories, friendships, and affects of young victims - who are not linked to illegal groups and/or do not have "information" - and of defenseless older adults are controlled.

Maltrato institucional hacia el adulto mayor: percepciones del prestador de servicios de salud y de los ancianos / Institutional abuse toward the elderly: Perceptions of health care providers and older adults

Objetivo. Analizar la percepción que el prestador de servicios de salud y el adulto mayor (AM) tienen sobre el maltrato al AM en los servicios públicos de salud, en ciudades seleccionadas de México. Material y métodos. De 2009 a 2012 se realizó un estudio con diseño cualitativo y estrategia de triangulación de fuentes de datos; se efectuaron entrevistas semiestructuradas a 13 prestadores y a 12 ancianos para recuperar su experiencia en el tema. El análisis utilizó procedimientos de la Teoría Fundamentada. Resultados. El maltrato contra el AM es una práctica naturalizada por el personal y por el anciano, la cual se manifiesta de formas diversas. Conclusiones. La institucionalización, profesionalización histórica y falta de conciencia sobre las necesidades de los AM demandan cambios de planeación, organización y supervisión del Sistema de Salud. El personal requiere intervenciones de formación, capacitación y cambio de actitudes/comportamiento, para otorgar atención integral, digna, humana y de respeto a los Derechos Humanos de los AM.

Objective. To analyze the health care providers (HCP) and elderly patients' perceptions about abuse of the elderly by health personnel of public health services, in selected cities in Mexico. Materials and methods. A qualitative study and a strategy of data triangulation were performed during 2009 and 2012; 13 HCPs and 12 elders were interviewed, in order to obtain their experience regarding elder abuse. Grounded Theory proceedings were used for the analysis. Results. Elder abuse is a naturalized practice, from HCP and elderly people's point of view; these perceptions are showed in different ways. Conclusion. Institutionalization, historical professionalization and lack of consciousness about needs of the elderly (sociocultural and economic), require changes in planning, organization and monitoring process in the Health System; training and educational interventions on staff and exchange attitudes and behavior are necessary in order to offer a health care that is comprehensive, decent, human and with respect for the human rights.

Assessment of primary health care: health professionals’ perspective / Evaluación de la atención primária em la salud: vision de los profissionales de la salud / Avaliação da Atenção Primária à Saúde: visão dos profissionais de saúde

Objective To assess primary health care attributes of access to a first contact, comprehensiveness, coordination, continuity, family guidance and community orientation. Method An evaluative, quantitative and cross-sectional study with 35 professional teams in the Family Health Program of the Alfenas region, Minas Gerais, Brazil. Data collection was done with the Primary Care Assessment Tool - Brazil, professional version. Results Results revealed a low percentage of medical experts among the participants who evaluated the attributes with high scores, with the exception of access to a first contact. Data analysis revealed needs for improvement: hours of service; forms of communication between clients and healthcare services and between clients and professionals; the mechanism of counter-referral. Conclusion It was concluded that there is a mismatch between the provision of services and the needs of the population, which compromises the quality of primary health care.


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Objetivo Evaluar la atención primaria de salud a través de las cualidades: Acesso de Primero Contacto, Intregidad, Coordinación, Longitudinalidad, Orientación Familiar, Orientación Comunitaria. Método Se trata de una evaluación cuantitativa y estudio transverso con 35 equipos de profesionales de la Estrategia de Salud de la Familia, de región de Alfenas, Minas Gerais, Brasil. Para recopilar los datos, se utilizó el Instrumento de Evaluación de la Atención Primaria - Brasil , la versión Professional. Resultados Los datos revelaron un bajo porcentaje de especialistas médicos en Atencion Primaria de Salud. Los participantes evaluó las calidades con puntajes altos, con la excepción de Acceso Primero Contacto. El análisis de datos reveló una mejora necesidades: horarios de apertura de los servicios; las formas de comunicación entre el usuario y el servicio y entre el usuario y el profesional, la remissión y consulta. Conclusión Existe un desajuste entre la oferta de servicios y las necesidades de la población, lo que compromete la calidad de la Atención Primaria de Salud.
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Objetivo Avaliar a Atenção Primária à Saúde por meio dos atributos: Acesso de Primeiro Contato, Integralidade, Coordenação, Longitudinalidade, Orientação Familiar, Orientação Comunitária. Método Estudo avaliativo, quantitativo e transversal, realizado com 34 profissionais de equipes da Estratégia de Saúde da Família da microrregião de Alfenas, Minas Gerais, Brasil. Para a coleta de dados, foi utilizado o Primary Care Assessment Tool – Brasil, versão profissionais. Resultados Os dados revelaram baixo percentual de profissionais médicos especialistas em Atenção Primária à Saúde. Os participantes avaliaram os atributos com altos escores, com exceção do Acesso de Primeiro Contato. A análise dos dados revelou necessidades de aperfeiçoamento: o horário de funcionamento dos serviços; as formas de comunicação entre usuário e serviço, e entre usuário e profissionais; o mecanismo de contrarreferência. Conclusão Existe um descompasso entre a oferta de serviços e as necessidades da população que compromete a qualidade da Atenção Primária a Saúde.
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Emancipatory practices of nurses in primary health care: the home visit as an instrument of health needs assessment / Prácticas emancipadoras del enfermero en la atención primaria de salud: la visita domiciliaria como instrumento de reconocimiento de necesidades de la salud / Práticas emancipatórias de enfermeiros na Atenção Básica à Saúde: a visita domiciliar como instrumento de reconhecimento de necessidades de saúde

Objective Identify nurses’ emancipatory practices in primary care, to contribute to the improvement of health care. Method A case study type social research of qualitative nature, in which nurses of a primary health care service unit in São Paulo were interviewed. Results The home visit was identified as a nursing practice possible to be expanded in order to identify social determinants of health, triggering emancipatory practices in the service. This expansion occurred because the design of health care labour intended by the service team changed its focus from the traditional object of health services, the disease. Conclusion First, it is advocated that social policies lead projects with the purpose of improving health needs. On the other hand, the daily labour needs to provide opportunities for reflection and discussion of healthcare projects, leading workers to propose labour-processes targeted to both the social determinants of health and people’s illness. .

Objetivo Identificar las prácticas emancipadoras de enfermeras en Unidad de Salud Familiar fueron el objeto de este estudio. Método La investigación social cualitativa tipo estúdio de caso. Fueron entrevistados enfermeros de una Unidad de Salud Familiar en Sao Paulo. Resultados Se identificó que la Visita Domiciliaria ha ampliado su alcance y identificado determinantes del proceso salud-enfermedad, lo que provocó en la Unidad de Salud Familiar prácticas emancipadoras. Esta expansión se produjo debido a que el diseño de la atención en propósito por la USF amplió el tradicional objeto de los servicios de salud. Conclusión Se aboga que las directrices de las políticas sociales basen proyectos que tengan como fin el mejoramiento de las necesidades de salud y que el trabajo diario proporcione la reflexión y discusión de los proyectos de atención, para proponer prácticas que enfoquen en los determinantes del proceso salud-enfermedad, tanto cuanto en sus resultados - la enfermedad en el cuerpo individual. .

Objetivo Identificar as práticas emancipatórias de enfermeiros da Atenção Primária, com a finalidade de contribuir para o aprimoramento do cuidado em saúde. Método Pesquisa social de natureza qualitativa, do tipo estudo de caso. Foram entrevistados os enfermeiros de uma Unidade de Saúde da Família em São Paulo. Resultados Identificou-se que a visita domiciliária, prática protocolar, ampliou seu escopo e identificou determinantes do processo saúde-doença, desencadeando na Unidade de Saúde da Família práticas emancipatórias. Essa ampliação ocorreu porque o projeto de cuidado intencionalizado ampliou o objeto tradicional dos serviços de saúde. Conclusão Advoga-se que as diretrizes das políticas sociais ancorem projetos que tomem como finalidade o aprimoramento das necessidades de saúde e que o cotidiano do trabalho proporcione reflexão e discussão dos projetos de cuidado, para intencionalizar práticas que incidam nos determinantes do processo saúde-doença, tanto quanto nos resultados - a doença expressa no corpo individual. .

Novel, low cost, highly effective, handmade steroid pellets for experimental studies.

The basic component of Silastic® glue (Dow Corning) used to prepare Silastic® pellets is polydimethylsiloxane. This compound is also present in other commercial adhesives such as FASTIX® (Akapol SA) that are available in any store for that category. In the present study we developed low cost, easy to prepare handmade steroid pellets (HMSP) by mixing 17ß-estradiol, progesterone or other synthetic steroids with FASTIX® adhesive. We assessed serum levels of 17ß-estradiol, progesterone, prolactin and luteinizing hormone in ovariectomized mice treated for 24 and 48 h or 7, 14 and 28 days with 20 µg or 5 mg of 17ß-estradiol or 5 mg progesterone HMSP. We found a time dependent and significant increase in the levels of both natural hormones, and a downregulation of serum luteinizing hormone levels, while both 17ß-estradiol doses increased serum prolactin. Uterine weights at sacrifice and histological examination of the uteri and the mammary glands correlated with estrogen or progestin action. Finally, we evaluated the biological effects of HMSP compared to commercial pellets or daily injections in the stimulation or inhibition of hormone dependent mammary tumor growth, and found that HMSP were as effective as the other methods of hormone administration. These data show that HMSP represent a useful, low cost, easily accessible method for administering steroids to mice.

In vitro assessment of the cytotoxic, apoptotic, and mutagenic potentials of isatin.

Isatin (1H-indole-2,3-dione) is a chemical found in various medicinal plant species and responsible for a broad spectrum of pharmacological and biological properties that may be beneficial to human health, as an anticonvulsant, antibacterial, antifungal, antiviral, and anticancer agent. The aim of the present study was to determine in vitro the cytotoxic, mutagenic, and apoptotic effects of isatin on CHO-K1 and HeLa cells using the MTT viability assay (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide), micronucleus (MN) test, apoptosis index, and nuclear division index (NDI). The 5 isatin concentrations evaluated in the mutagenicity and apoptosis tests were 0.5, 1, 5, 10, and 50 µM, selected through a preliminary MTT assay. Positive (doxorubicin, DXR) and negative (phosphate buffered saline, PBS) control groups were also included in the analysis. Isatin did not exert a mutagenic effect on CHO-K1 after 3 and 24 h of treatment or on HeLa cells after 24 h. However, 10 and 50 µM concentrations inhibited cell proliferation and promoted apoptosis in both CHO-K1 and HeLa cells. Data indicate that the cytotoxic, apoptotic, and antiproliferative effects of isatin were concentration independent and cell line independent.

Mathematical determination of cell population doubling times for multiple cell lines.

Cell cycle times are vital parameters in cancer research, and short cell cycle times are often related to poor survival of cancer patients. A method for experimental estimation of cell cycle times, or doubling times of cultured cancer cell populations, based on addition of paclitaxel (an inhibitor of cell division) has been proposed in literature. We use a mathematical model to investigate relationships between essential parameters of the cell division cycle following inhibition of cell division. The reduction in the number of cells engaged in DNA replication reaches a plateau as the concentration of paclitaxel is increased; this can be determined experimentally. From our model we have derived a plateau log reduction formula for proliferating cells and established that there are linear relationships between the plateau log reduction values and the reciprocal of doubling times (i.e. growth rates of the populations). We have therefore provided theoretical justification of an important experimental technique to determine cell doubling times. Furthermore, we have applied Monte Carlo experiments to justify the suggested linear relationships used to estimate doubling time from 5-day cell culture assays. We show that our results are applicable to cancer cell populations with cell loss present.

Consideraciones para la transformación del sistema de salud del Ecuador desde una perspectiva de equidad / Equity-based considerations for transforming the Ecuadorian health system

Objectivo El propósito del presente estudio es analizar las inequidades socioeconómicas en la utilización de servicios de salud en el Ecuador, las inequidades en la distribución geográfica de recursos humanos en salud, y reflexionar sobre los retos de equidad que el sistema de salud ecuatoriano enfrenta en la actualidad. Métodos Se utilizó la Encuesta Demográfica y de Salud Materno-Infantil (ENDEMAIN 2004) como la principal fuente de datos, cuya muestra es representativa de la población ecuatoriana. Para estimar los efectos en utilización de servicios de salud utilizamos análisis multivariado multinivel (usando el paquete estadístico MLWiN 2.02) y análisis espacial de recursos en salud (usando GeoDa 1.0.1 ). Resultados Nuestro análisis encontró que inequidades sociales, económicas y geográficas limitan el acceso a servicios de salud en el Ecuador. Hogares de bajos recursos, indígenas y aquellos que viven enáreas rurales (muchos con las tres características a la vez) tienen menos posibilidades de utilizar servicios de salud. A pesar de la marcada concentración de proveedores de salud en zonas urbanas, encontramos que la presencia de personal de salud (excluyendo a médicos) en entidades públicas rurales incrementa la posibilidad de utilización de servicios preventivos y curativos. Conclusiones Los esfuerzos para transformar el sistema de salud deben reducir barreras sociales, culturales, financieras; y las desigualdades en la distribución de recursos humanos en salud, particularmente en elárea rural. Consideramos que la orientación comunitaria y familiar de los servicios, y el incremento de espacios de participación ciudadana son necesarios para reducir dichas inequidades.

Objective The present study was aimed at analysing socioeconomic inequity regarding the use of health services in Ecuador, inequity regarding the geographic distribution of healthcare-related human resources and reflecting on the challenges concerning equity which the Ecuadorian health system is currently facing. Methods The Ecuadorian Demographic, Maternal and Infant Health Survey (2004) was used as the main data source, as its sample was representative of the Ecuadorian population. Multilevel multivariate analysis (MLWiN 2.02 statistical software) and spatial data analysis regarding health resources (GeoDa 1.0.1) were used for estimating the effects of using health services. Results It was found that social, economic and geographic inequity limited access to health services in Ecuador. People living in low economic resource households or indigenous housing and people living in rural areas (many of them having all three characteristics at the same time) had less possibility of using health services. In spite of a marked concentration of health-service providers in urban areas, it was found that the presence of healthcare personnel (excluding doctors) in rural public entities increased the possibility of using preventative and curative services. Conclusions Efforts at transforming the Ecuadorian health system must be aimed at reducing social, cultural and financial barriers and inequality regarding the distribution de healthcare-related human resources, particularly in rural areas. Community and family orientation of the services and increasing spaces for citizen participation are necessary for reducing such inequity.

Cetuximab (erbitux).

Cetuximab, a recombinant chimeric monoclonal antibody, has been successfully used in the treatment of the head and neck and colorectal cancers. We present a review of its mechanism of action, indications, side effects and economic issues, accompanied by a clinical example from our institution.

Different genotoxic profiles between depleted and enriched uranium.

Uranium is an alpha-particle-emitting heavy metal. Its genotoxicity results from both its chemical and its radiological properties that vary with its isotopic composition (12% enriched uranium in (235)U (EU) has a specific activity 20 times higher than 0.3% depleted uranium in (235)U (DU)). The influence of the isotopic composition of uranium on its genotoxic profile (clastogenic/aneugenic) has never been described. The present study evaluated genotoxic profile of uranium with the cytokinesis-block micronucleus centromere assay. C3H10T1/2 mouse embryo fibroblasts were contaminated with either DU or EU at different concentrations (5 microM, 50 microM and 500 microM). Cells received low doses ranging from 0.3 microGy to 760.5 microGy. The frequency of binucleated cells with one micronucleus increased with increasing concentrations of both DU and EU in the same way. EU induced more centromere-negative micronuclei and nucleoplasmic bridges than DU. A correlation between these two clastogenic markers and ionizing radiation doses was observed. Finally, this study showed that the genotoxic profile of uranium depends on its isotopic composition. DU and EU are low and high clastogens, respectively. However, DU aneugenic effects remain high. Thus, there is a need to study the potential role of aneugenic effects of DU in carcinogenic risk assessment linked to uranium internal exposure.

The fitness cost of streptomycin resistance depends on rpsL mutation, carbon source and RpoS (sigmaS).

Mutations that cause antibiotic resistance often produce associated fitness costs. These costs have a detrimental effect on the fate of resistant organisms in natural populations and could be exploited in designing drugs, therapeutic regimes, and intervention strategies. The streptomycin resistance (StrR) mutations K42N and P90S in ribosomal protein S12 impair growth on rich medium. Surprisingly, in media with poorer carbon sources, the same StrR mutants grow faster than wild type. This improvement reflects a failure of these StrR mutants to induce the stress-inducible sigma factor RpoS (sigmaS), a key regulator of many stationary-phase and stress-inducible genes. On poorer carbon sources, wild-type cells induce sigmaS, which retards growth. By not inducing sigmaS, StrR mutants escape this self-imposed inhibition. Consistent with this interpretation, the StrR mutant loses its advantage over wild type when both strains lack an RpoS (sigmaS) gene. Failure to induce sigmaS produced the following side effects: (1) impaired induction of several stress-inducible genes, (2) reduced tolerance to thermal stress, and (3) reduced translational fidelity. These results suggest that RpoS may contribute to long-term cell survival, while actually limiting short-term growth rate under restrictive growth conditions. Accordingly, the StrR mutant avoids short-term growth limitation but is sensitized to other stresses. These results highlight the importance of measuring fitness costs under multiple experimental conditions not only to acquire a more relevant estimate of fitness, but also to reveal novel physiological weaknesses exploitable for drug development.

Assessment of lymphocyte proliferation: CFSE kills dividing cells and modulates expression of activation markers.

The measurement of cell proliferation after mitogenic stimulation is an important parameter used in diagnosis of immunodeficiencies in clinical laboratory as well as in various fields of lymphocyte research. Recent methods try to overcome the radioactive assay using tritiated thymidine ((3)H) by flow-cytometric methods using different fluorochromes such as CFSE or even to substitute these direct methods by tracing the expression of cell-membrane activation markers associated with various steps of proliferation cycle. In our study we compared the (3)H assay with CFSE-staining method and expression of activation markers (CD69, HLA-DR, CD25, CD27, CD71, CD152, CD134 and CD195) on a sample of 128 consecutive patients and healthy controls evaluated in clinical laboratory. We also tested various concentrations of CFSE and its impact on proliferation activity and expression of activation markers. We found that CFSE in concentration from 37nM to 10microM decreases the proliferative capacity (expressed in cpm (3)H assay) due to the decreased viability of proliferating cells (measured as 7-AAD+) in concentration-dependent manner. Moreover, CFSE substantially modulates the expression of activation molecules (decreasing CD69, HLA-DR, CD25 the majority of examinated molecules). We found a good correlation between CFSE-staining method with (3)H assay, if CFSE low population is gated on CD3+ population (correlation coefficient 0.801), but only in samples with stimulation index (SI) higher then 25. In poorly proliferating samples (SI25) no correlation was found due to several false positive results in CFSE test. Statistically significant correlation between proliferation assessed as (3)H-thymidine incorporation and expression of activation markers was found in the case of CD25, CD27, CD38, CD152, CD71, still only in samples with higher proliferation activity (SI>25). No correlation was found with CD134, CD195, HLA-DR and CD69. We conclude that standard assay with (3)H-thymidine incorporation is unreplaceable assay in diagnosis of severe cellular immunodeficiencies as CFSE assay have high proportion of false positive results. Researchers tracing cell-membrane bound molecules on dividing cells stained by CFSE must take into account that CFSE may substantially modulate the expression of these markers and decrease the viability of stained cells.

Efficacy of delayed administration of post-chemotherapy granulocyte colony-stimulating factor: evidence from murine studies of bone marrow cell kinetics.

The optimal schedule of post-chemotherapy granulocyte colony-stimulating factor (G-CSF) administration has not been determined. G-CSF is customarily started 24 hours after chemotherapy; however, clinical data demonstrated that delaying G-CSF until 5 days after completion of chemotherapy has not resulted in a longer duration of neutropenia. Here, we examined the optimal timing of post-chemotherapy G-CSF administration in a mouse model, to show that delayed administration does not postpone the appearance of mature granulocytes in the peripheral blood. We also investigated the mechanism of decreased efficacy of the early G-CSF application after chemotherapy by characterizing the changes in bone marrow cellular composition. To our knowledge, we demonstrate for the first time, that early after chemotherapy, the bone marrow is predominantly composed of mature residual granulocytes and very few progenitors and precursors, on which G-CSF would act to generate granulocytes. The point when immature progenitors reappear does not occur in murine bone marrow until 48 hours after a single dose of cyclophosphamide. Our results indicate that the bone marrow cellular composition early after discontinuation of chemotherapy is not optimal for G-CSF action on acceleration of myeloid recovery. Given the high cost of G-CSF prophylaxis, its delayed administration may potentially result in substantial economic benefits.

Assessment of cell proliferation by 5-bromodeoxyuridine (BrdU) labeling for multicolor flow cytometry.

Cell proliferation assays are used for a large variety of applications in the life sciences. This unit describes a flow-cytometry-based method that uses BrdU labeling in conjunction with multiple fluorescently labeled cell surface markers, allowing extensive phenotypic characterization of dividing cells in addition to assessment of their frequency. BrdU labeling has the advantage of constituting a nonradioactive technique that, when combined with additional fluorescent-based reagents, avoids time-consuming and often costly cell isolation procedures. Moreover, because BrdU is stably integrated into the DNA, it can be measured in a cell for many months. The method presented in this unit is based on paraformaldehyde fixation and reversible saponin-based cell membrane permeabilization, which maintains cell integrity as well as fluorescent labeling with a large number of different fluorochromes, allowing 10- to 12-color flow cytometric analysis of proliferating cells.

The fallacies of hope: will we discover new antibiotics to combat pathogenic bacteria in time?

While newly developed technologies have revolutionized the classical approaches to combating infectious diseases, the difficulties associated with developing novel antimicrobials mean that these technologies have not yet been used to introduce new compounds into the market. The new technologies, including genomics and structural biology, open up exciting possibilities for the discovery of antibiotics. However, a substantial effort to pursue research, and moreover to incorporate the results into the production chain, is required in order to bring new antimicrobials to the final user. In the current scenario of emerging diseases and the rapid spread of antibiotic resistance, an active policy to support these requirements is vital. Otherwise, many valuable programmes may never be fully developed for lack of "interest" and funds (private and public). Will we react in time to avoid potential disaster?

Genotoxicity assessment of deoxynivalenol in the Caco-2 cell line model using the Comet assay.

The genotoxic risk associated with deoxynivalenol (DON), a prevalent trichothecene mycotoxin which contaminates cereal-based products has not yet been deeply explored. In this work, the alkaline version of the Comet assay was used to evaluate DNA damage stemming from DON exposure in both dividing and differentiated Caco-2 cells, an epithelial intestinal cell line. To avoid false positive results, cytotoxic and apoptotic thresholds were firstly established using the MTS and neutral red assays and the Hoestch staining method, respectively. Dividing cells were found to be more sensitive to DON than differentiated cells and the lowest IC(10) (0.5 microM) obtained for dividing cells exposed for 72 h was used as the highest working concentration in the genotoxicity study. Both differentiated and dividing cells responded with a dose-dependent relationship to DON in terms of DNA damage in the 0.01-0.5 microM range. These results demonstrated the existence of a genotoxic potential for DON at low concentrations compatible with actual exposure situations and calls for additional studies to determine the functional consequences which could be taken into account for the risk assessment of this food contaminant.