Antioxidant-mediated control of degradation and drug release from surface-eroding poly(ethylene carbonate).

Surface-eroding polymers are of significant interest for various applications in the field of controlled drug delivery. Poly(ethylene carbonate), as an example, offers little control over the rate of degradation and, thus, drug release, which usually conflicts with the requirements for long-acting medications. Here, we challenged an option to decelerate the degradation of poly(ethylene carbonate) in vitro and in vivo. When polymer films loaded with distinct antioxidants (vitamins) along with the model drugs leuprorelin and risperidone were incubated in superoxide radical solution and phagocyte culture, the mass loss and drug release from the delivery vehicle was a function of the type and dose of the utilized antioxidant. Once the polymer surface was "attacked" by reactive oxygen species, the antioxidants were released on demand quenching the polymer-degrading radicals. Accordingly, specific combinations of polymer and radical scavengers resulted in controlled release medications with an extended "life-time" of one month or longer, which is difficult to achieve for poly(ethylene carbonate) in the absence of antioxidants. A comparable degradation and drug release behavior was observed when antioxidant-loaded poly(ethylene carbonate) films were implanted in rats. Furthermore, linear correlations were obtained between the mass loss of the polymer films and the released fraction of drug (with slopes close to 1), a clear indication for the surface erosion of poly(ethylene carbonate) in vitro and in vivo. Overall, an addition of antioxidants to poly(ethylene carbonate)-based controlled drug delivery vehicles represents a reasonable approach to modify the performance of long-acting medications, especially when a "life time" of weeks to months needs to be achieved. STATEMENT OF SIGNIFICANCE: Surface-eroding poly(ethylene carbonate) (PEC) is of significant interest for long-acting injectable formulations. However, PEC offers only little control over the rate of degradation and, thus, drug release kinetics. We describe an option to decelerate the degradation rate of PEC in vitro and in vivo. When polymer films loaded with distinct antioxidants along with model drugs were incubated in superoxide radical solution, phagocyte culture and implanted in rats, their mass loss and drug release was a function of the type and dose of the utilized antioxidant. Accordingly, specific combinations of polymer and radical scavengers resulted in controlled release medications with an extended "life-time" of one month or longer, which is difficult to achieve for PEC in the absence of antioxidants.

Validación del Índice Funcional para Osteoartritis de Manos (FIHOA) en pacientes con artritis reumatoidea / Validation of the Functional Index for Hand Osteoarthritis (FIHOA) in patients with rheumatoid arthritis

El FIHOA fue desarrollado para evaluar la capacidad funcional de pacientes con OA de manos. Objetivo: Validar FIHOA en pacientes con AR. Métodos: Estudio analítico, observacional prospectivo de corte transversal. Se incluyeron pacientes consecutivos con diagnóstico de AR (ACR/EULAR 2010). Se consignaron datos demográficos y características de la enfermedad. Todos los pacientes completaron los siguientes cuestionarios autoadministrados: FIHOA, HAQ-A, HAQ-UP-A y Quick DASH. En un subgrupo de pacientes, una terapista ocupacional valoró la capacidad funcional de la mano por medio del test de SODA-A. Se evaluó la reproducibilidad de FIHOA. Análisis estadístico: Estadística descriptiva. Confiabilidad con test de Cronbach. Validez de constructo con correlación de Spearman. Reproducibilidad test re-test. Modelo de regresión lineal. Resultados: Se incluyeron 100 pacientes. La prueba alfa de Cronbach fue de 0,94. No se evidenciaron preguntas redundantes. El FIHOA mostró excelente correlación con HAQ-A (r=0,89); HAQ-UP-A (r=0,89); Quick DASH (r=0,90) y SODA-A (r=-0,80); y buena correlación con DAS28-ERS (r=0,65), y con otros parámetros de la enfermedad. La reproducibilidad fue 0,73. La regresión lineal múltiple mostró como principal determinante del FIHOA a la presencia de rigidez matinal seguida por el uso de corticoides y el EVA general de pacientes. Conclusión: El FIHOA resultó ser confiable, válido y reproducible en pacientes con AR

FIHOA was developed to evaluate the functional capacity of patients with OA hands. Objetive: To validate FIHOA in patients with RA. Methods: Analytical, observational, prospective cross-sectional study. Consecutive patients with diagnosis of RA (ACR/EULAR 2010) were included. Demographic and RA characteristics were recorded. Patients completed the following self-administered questionnaires: FIHOA, HAQ-A, HAQ-UP-A and Quick DASH. For a patient subgroup, an occupational therapist performed an objective evaluation of the functional capacity of the hands using the SODA-A. Reproducibility was assessed. Statistical analysis: Descriptive statistics. Reliability with the Cronbach test. Construct validity with Spearman correlation. Reproducibility with test-retest reliability. Linear regression model. Results: One hundred patients were included. Cronbach's alpha test was 0.94. There were no redundant questions. FIHOA showed an excellent correlation with HAQ-A (r=0.89); HAQUP-A (r=0.89); Quick DASH (r=0.90) and SODA-A (r=-0.80); and a good correlation with DAS28- ERS (r=0.65) and with other disease parameters. Questionnaire reproducibility was 0.73. A multiple linear regression showed morning stiffness as the main determinant of FIHOA, followed by glucocorticoid use and patient global assessment. Conclusion: FIHOA was found to be reliable, valid and reproducible in patients with RA

Patrones de tratamiento, sobrevida y efectividad a largo plazo de agentes biológicos en pacientes con Artritis Psoriásica / Patterns of treatment, survival and long-term effectiveness of biological agents in patients with Psoriatic Arthritis

Objetivos: Evaluar los patrones de tratamiento de las DME-b (Drogas Modificadoras de la Enfermedad-biológicas), su sobrevida acumulada y su eficacia a largo plazo en pacientes con Artritis Psoriásica (APs) utilizando el índice LUNDEX. Materiales y métodos: Estudio multicéntrico retrospectivo. Se incluyeron pacientes con diagnóstico de APs que hayan iniciado tratamiento con DME-b. Se recolectaron datos sociodemográficos y clínicos. Se consignaron fechas de inicio de DME-b, tratamiento concomitante, suspensión o cambio de tratamiento, y razones de suspensión. La respuesta terapéutica se definió acorde a MDA (Minimal Disease Activity), a los 6, 12 meses y anualmente a partir del inicio de DME-b. Análisis estadístico: Test de Student y Chi². Curvas de Kaplan Meier y Log Rank. Análisis de regresión de Cox. Resultados: Se incluyeron 72 pacientes con APs, 39 (54,2%) de sexo masculino. La edad mediana fue de 54,5 años (RIC 45-61) y el tiempo mediano de evolución de la enfermedad de 11 años (RIC 6-15). 71,2% (n=42) presentaron comorbilidades. El primer DME-b fue en orden decreciente de frecuencia: Adalimumab (45,8%), Etanercept (36,1%), Certolizumab (5,6%), Infliximab (4,2%), Ustekinumab (4,2%), Abatacept (2,7%) y Golimumab (1,4%). 15 pacientes (25,4%) recibieron DME-b en monoterapia. La sobrevida media fue de 82 meses (DE±7,4). El LUNDEX del primer biológico fue 24,7% a los 6 meses y 44,3% al año. La sobrevida media de Adalimumab fue de 90 meses (DE±10,4) y de Etanercept 79 meses (DE±12). Los pacientes añosos presentaron menor sobrevida de la droga [≥55 años: X59,8 (DE±10,5) vs <55 años: X101,2 (DE±9,7), p=0,006]. Luego de ajustar por diferentes confundidores, la edad ≥55 años se mantuvo significativamente a menor sobrevida [HR=1,064 (IC=1,01-1,11) p=0,005]. El LUNDEX fue menor en obesos vs no obesos (16% vs 66% al año, p=0,89; 10,5 vs 74,9% a los 2 años, p=0,011 y 5,9 vs 81,8% a los 3 años, p=0,005). Conclusiones: La sobrevida promedio del primer DME-b fue de 6,8 años. La única variable asociada a menor sobrevida fue la mayor edad.

Objectives: To evaluate the treatment patterns of DME-b (Disease-Modifying Drugs-biological), their accumulated survival and their long-term efficacy in patients with psoriatic arthritis (PsA) using the LUNDEX index. Materials and methods: Retrospective multicentre study. We included patients diagnosed with PsA who started treatment with DME-b. Sociodemographic and clinical data were collected. BMI-D start dates, concomitant treatment, suspension or change of treatment, and reasons for suspension were recorded. The therapeutic response was defined according to MDA (Minimal Disease Activity), at 6, 12 months and annually from the beginning of DME-b. Statistical analysis: Student test and Chi². Curves of Kaplan Meier and Log Rank. Cox regression analysis. Results: We included 72 patients with PsA, 39 (54.2%) male. The median age was 54.5 years (IQR 45-61) and the median time of evolution of the disease was 11 years (IQR 6-15). 71.2% (n=42) presented comorbidities. The first DME-b was in decreasing order of frequency: Adalimumab (45.8%), Etanercept (36.1%), Certolizumab (5.6%), Infliximab (4.2%), Ustekinumab (4.2%), Abatacept (2.7%) and Golimumab (1.4%). 15 patients (25.4%) received DME-b monotherapy. The mean survival was 82 months (SD±7.4). The LUNDEX of the first biological was 24.7% at 6 months and 44.3% per year. The mean survival of Adalimumab was 90 months (SD±10.4) and Etanercept 79 months (SD±12). Older patients had a lower survival of the drug [≥55 years: X59.8 (SD±10.5) vs <55 years: X101.2 (SD±9.7), p=0.006]. After adjusting for different confounders, age ≥55 years was significantly maintained at lower survival [HR=1.064 (CI=1.01-1.11) p=0.005]. The LUNDEX was lower in obese vs. non-obese (16% vs. 66% per year, p=0.89, 10.5 vs 74.9% at 2 years, p=0.011 and 5.9 vs 81.8% at 3 years, p=0.005). Conclusions: The average survival of the first DME-b was 6.8 years. The only variable associated with lower survival was the older age.

Developmental Injury to the Cerebellar Cortex Following Hydroxyurea Treatment in Early Postnatal Life: An Immunohistochemical and Electron Microscopic Study.

Postnatal development of the cerebellar cortex was studied in rats administered with a single dose (2 mg/g) of the cytotoxic agent hydroxyurea (HU) on postnatal day (P) 9 and collected at appropriate times ranging from 6 h to 45 days. Quantification of several parameters such as the density of pyknotic, mitotic, BrdU-positive, and vimentin-stained cells revealed that HU compromises the survival of the external granular layer (EGL) cells. Moreover, vimentin immunocytochemistry revealed overexpression and thicker immunoreactive glial processes in HU-treated rats. On the other hand, we also show that HU leads to the activation of apoptotic cellular events, resulting in a substantial number of dying EGL cells, as revealed by TUNEL staining and at the electron microscope level. Additionally, we quantified several features of the cerebellar cortex of rats exposed to HU in early postnatal life and collected in adulthood. Data analysis indicated that the analyzed parameters were less pronounced in rats administered with this agent. Moreover, we observed several alterations in the cerebellar cortex cytoarchitecture of rats injected with HU. Anomalies included ectopic placement of Purkinje cells and abnormities in the dendritic arbor of these macroneurons. Ectopic granule cells were also found in the molecular layer. These findings provide a clue for investigating the mechanisms of HU-induced toxicity during the development of the central nervous system. Our results also suggest that it is essential to avoid underestimating the adverse effects of this hydroxylated analog of urea when administered during early postnatal life.

Hydroxyurea Treatment and Development of the Rat Cerebellum: Effects on the Neurogenetic Profiles and Settled Patterns of Purkinje Cells and Deep Cerebellar Nuclei Neurons.

The current paper analyzes the development of the male and female rat cerebellum exposed to hydroxyurea (HU) (300 or 600 mg/kg) as embryo and collected at postnatal day 90. Our study reveals that the administration of this drug compromises neither the cytoarchitecture of the cerebellar cortex nor deep nuclei (DCN). However, in comparison with the saline group, we observed that several cerebellar parameters were lower in the HU injected groups. These parameters included area of the cerebellum, cerebellar cortex length, molecular layer area, Purkinje cell number, granule cell counts, internal granular layer, white matter and cerebellar nuclei areas, and number of deep cerebellar nuclei neurons. These features were larger in the rats injected with saline, smaller in those exposed to 300 mg/kg of HU and smallest in the group receiving 600 mg/kg of this agent. No sex differences in the effect of the HU were observed. In addition, we infer the neurogenetic timetables and the neurogenetic gradients of PCs and DCN neurons in rats exposed to either saline or HU as embryos. For this purpose, 5-bromo-2'-deoxyuridine was injected into pregnant rats previously administered with saline or HU. This thymidine analog was administered following a progressively delayed cumulative labeling method. The data presented here show that systematic differences exist in the pattern of neurogenesis and in the spatial location of cerebellar neurons between rats injected with saline or HU. No sex differences in the effect of the HU were observed. These findings have implications for the administration of this compound to women in gestation as the effects of HU on the development of the cerebellum might persist throughout their offsprings' life.

Sexual communication in day-flying Lepidoptera with special reference to castniids or 'butterfly-moths'.

Butterflies and moths are subject to different evolutionary pressures that affect several aspects of their behaviour and physiology, particularly sexual communication. Butterflies are day-flying insects (excluding hedylids) whose partner-finding strategy is mainly based on visual cues and female butterflies having apparently lost the typical sex pheromone glands. Moths, in contrast, are mostly night-flyers and use female-released long-range pheromones for partner-finding. However, some moth families are exclusively day-flyers, and therefore subject to evolutionary pressures similar to those endured by butterflies. Among them, the Castniidae, also called 'butterfly-moths' or 'sun-moths', behave like butterflies and, thus, castniid females appear to have also lost their pheromone glands, an unparallel attribute in the world of moths. In this paper, we review the sexual communication strategy in day-flying Lepidoptera, mainly butterflies (superfamily Papilionoidea), Zygaenidae and Castniidae moths, and compare their mating behaviour with that of moth families of nocturnal habits, paying particular attention to the recently discovered butterfly-like partner-finding strategy of castniids and the fascinating facts and debates that led to its discovery.

Generation and vulnerability of deep cerebellar nuclei neurons in the weaver condition along the anteroposterior and mediolateral axes.

Production and death of deep cerebellar nuclei (DCN) neurons were investigated in the weaver condition at appropriate anatomical levels throughout the mediolateral (medial, intermediate and lateral) and rostrocaudal (rostral, middle and caudal) axes of three DCN-cell groups: the fastigial, the interposed and the dentate nuclei. Current results have denoted that the deficit of DCN neurons is always more important in the homozygous weaver than in the heterozygous weaver mice. No loss of neurons was found in the dentate nucleus. In the mediolateral axis, an intranuclear gradient of depletion was observed in the mutant mice; in a given deep nucleus, neurodegeneration was more prominent in the medial pars than in lateral ones. In the rostrocaudal axis, on the other hand, when each deep nucleus was studied and compared as a whole, neuron loss was higher in the fastigial nucleus than in the interposed nucleus, which, in turn, was more important than in the dentate nucleus. These data suggest that, in the weaver condition, an internuclear gradient of neurodegeneration exists. Moreover, neurons located in rostral parts of a given nucleus appear to be more vulnerable than those settled in middle parts and these, in turn, are more than the caudal ones. These results seem to indicate the presence of an intranuclear gradient of depletion. Current autoradiographic results have revealed that, in the rostrocaudal axis, deep neurons are settled in the weaver cerebellum following three neurogenetic gradients. The first of these is internuclear; if each deep nucleus is analyzed and compared as a whole, the fastigial nucleus has more late-generated neurons than the interposed nucleus, and this, in turn, has more than the dentate nucleus. The second gradient is also internuclear; if the proportion of late-born neurons is compared throughout the rostral levels from each deep nucleus, it is observed that proportions increase from the fastigial to the dentate nucleus. A similar picture emerges when the middle and caudal regions are taken into account. The third gradient is intranuclear; in a given deep nucleus, the rostral region always presents more late-produced neurons than the middle region and these, in turn, more than in the caudal level.

Systematic differences in time of cerebellar-neuron origin derived from bromodeoxyuridine immunoperoxidase staining protocols and tritiated thymidine autoradiography: A comparative study.

As exogenous markers of DNA synthesis, 5-bromo-2'-deoxyuridine (BrdU) and tritiated thymidine ([(3)H]TdR) have revolutionized our ability to identify proliferating neuroblasts and follow their fate during the development of the central nervous system. The effect of the incorporation of these molecules into DNA on cell proliferation, migration and differentiation is frequently neglected (Duque and Rakic, 2011. J. Neurosci. 31, 15205-15217). By a progressively delayed cumulative labeling method, the current paper analyzes the development of the cerebellum in mice exposed to either BrdU or [(3)H]TdR as embryos and collected at postnatal day 90. We observed that, in comparison to the saline group, several parameters of the cerebellum such as length of the cerebellar cortex, the area of the molecular layer, Purkinje cell (PCs) number, the areas of the cerebellar nuclei, and the number of the deep cerebellar nuclei (DCN) neurons were lower in the BrdU injected group. No consequence of [(3)H]TdR administration was observed. On the other hand, we also studied whether immunohistochemical methods, including BrdU antibodies from different vendors (Sigma and Dako), partial DNA denaturation procedures and trypsin pretreatments, alter the neurogenetic timetables of PC and DCN neurons that resulted from analysis of these tissue specimens. Our analysis revealed that the generative programs of these macroneurons were unrelated to differences in the sensibility of BrdU antibodies but were dependent on the partial denaturation of DNA and trypsin digestion protocols. Finally, we also compare the generation and spatial distribution of PC and DCN neurons in mice exposed to either BrdU or [(3)H]TdR to assess whether the results obtained by these two markers are quantitatively similar. The data presented here show that systematic differences exist in the pattern of neurogenesis and the spatial location of cerebellar neurons between mice injected with BrdU or [(3)H]TdR. These findings have implications for the interpretation of results obtained by both exogenous makers as an index of the production, migration and settling of neurons in the developing central nervous system.

Consumo de antiinflamatorios no esteroideos en pacientes que concurren por primera vez a un servicio de reumatología / Consumption of nonsteroidal anti-inflammaroty drug in patients attending for the first time a rehumatologic Unit

Introducción: El uso de antiinflamatorios no esteroideos (AINES) conlleva una mayor probabilidad de enfermedad gastrointestinal y cardiovascular en pacientes con factores de riesgo. Por tal motivo, se desarrollaron diversas recomendaciones con el fin de prevenir dichas complicaciones. Objetivo: Evaluar la frecuencia del consumo de AINES al momento de consultar por primera vez a un Servicio de Reumatología de demanda espontánea; y analizar tanto la conducta del médico así como el correcto cumplimiento de las recomendaciones para la toma de estos fármacos al finalizar la consulta. Material y métodos: Estudio observacional de corte transversal. Resultados: Se incluyeron 304 pacientes, 59,5% consumían AINES. La mayoría de estos pacientes presentaban riesgo gastrointestinal moderado/alto, sólo 28,3% recibían adecuada protección. De aquellos pacientes que recibían AINES, se consideró que requerían dicho tratamiento el 50%. Al finalizar la consulta, se tomó una conducta correcta en el 89% de los casos en relación al riesgo gastrointestinal. Conclusión: Más de la mitad de los pacientes consumían AINES. Se observó un buen cumplimiento de las recomendaciones por los médicos tratantes al finalizar la primera consulta. Sin embargo, es importante mencionar que el uso indiscriminado de AINES tanto por parte de los pacientes como por parte de los médicos sigue siendo alto.

Introduction: The use of Non-Steroidal Anti-Inflammatory DrugsNSAID (NSAIDS) leads to a higher probability of gastrointestinaland cardiovascular disease in patients with risk factors. Therefore,a number of recommendations were developed to prevent thesecomplications. The aim of this study was to evaluate the intake frequencyof NSAID by patients who attend to a rheumatology departmentfor the first time; and to analyze the attending physicians´ prescriptionas well as the correct implementation of the recommendationsfor the use of these drugs once this first visit was ended.Methods: We perform a cross-sectional observational study.Results: Three hundred and four patients were included, 59.5%were taking NSAIDs. Most of these patients had moderate/high gastrointestinalrisk and only 28.3% received adequate protection. Ofpatients receiving NSAIDs, it was considered that only 50% requiredsuch treatment. At the end of the first visit, the attending physiciansmade the correct implementation of the recommendations in 89%of cases in regard to gastrointestinal risk.Conclusion: More than half of the patients were taking NSAIDS.A good compliance with the recommendations by the attendingphysicians at the end of the first visit was observed. However, it isnoteworthy that the indiscriminate use of NSAIDs, both by patientsand by physicians, remains high.

Purkinje cell age-distribution in fissures and in foliar crowns: a comparative study in the weaver cerebellum.

Generation and settling of Purkinje cells (PCs) are investigated in the weaver mouse cerebellum in order to determine possible relationships with the fissuration pattern. Tritiated thymidine was supplied to pregnant females at the time that these neurons were being produced. Autoradiography was then applied on brain sections obtained from control and weaver offspring at postnatal (P) day 90. This makes it possible to assess the differential survival of neurons born at distinct embryonic times on the basis of the proportion of labeled cells located at the two foliar compartments: fissures and foliar crowns. Our data show that throughout the surface contour of the vermal lobes, generative programs of PCs were close between wild type and homozygous weaver. Similar data were found in the lobules of the lateral hemisphere. On the other hand, the loss of PCs in weaver cerebella can be related to foliar concavities or convexities depending on the vermal lobe or the hemispheric lobule studied. Lastly, we have obtained evidence that late-generated PCs of both normal and mutant mice were preferentially located in fissures. These quantitative relationships lead us to propose a model in which the final distribution of PCs through the vermal contour would be coupled to two factors: the cortical fissuration patterning and a "time-sequential effect" of weaver mutation.

Generation and survival of midbrain dopaminergic neurons in weaver mice.

Generation and survival of midbrain dopaminergic (DA) neurons were investigated using tyrosine hydroxylase (TH) immunocytochemistry combined with tritiated thymidine autoradiography at appropriate anatomical levels throughout the anteroposterior (A/P) axes of the substantia nigra pars compacta (SNc) and the ventral tegmental area (VTA). The wild-type (+/+) and homozygous weaver (wv/wv) mice used here were the offspring of pregnant dams injected with the radioactive precursor when the mesencephalic neurons were being produced (gestational days 11-15). Data reveal that, at postnatal day 90, depletion of TH-stained cells in the wv/wv presented an A/P pattern of increasing severity and, therefore, the DA cells located in posterior parts of the SNc or the VTA appear to be more vulnerable than the settled anterior neurons. When the time of neuron origin is inferred for each level of these cell groups, it is found that the neurogenesis span is similar for both experimental groups, although significant deficits in the frequency of wv/wv late-generated neurons were observed in any level considered. On the other hand, it has been found that TH-positive neurons were settled along the extent of the SNc and the VTA following precise and differential neurogenetic gradients. Thus, the acute rostrocaudal increase in the proportion of late-generated neurons detected in both+/+DA-cell groups is disturbed in the weaver homozygotes due to the indicated A/P depletion.

The weaver gene expression affects neuronal generation patterns depending on age and encephalic region.

Cell generation and survival are investigated in three different neuronal populations of weaver mice: Purkinje and fastigial neurons in the cerebellum, and dopaminergic neurons in the substantia nigra pars compacta. Tritiated thymidine was supplied to pregnant females at the time that these neurons were being produced. Autoradiography was then applied on brain sections obtained from the control and weaver offspring at postnatal (P) day 8 and 90. This makes it possible to assess the differential survival of neurons that were born at distinct embryonic times on the basis of the proportion of labeled cells at two postnatal ages. When labeling profiles were measured at P8, the inferred time of origin was similar between +/+ and wv/wv genotypes for each neuronal population considered. The same occurred at P90 for Purkinje or fastigial neurons, but the labeling profiles of midbrain neurons were different between wild type and weaver homozygotes. There is already a substantial reduction in the number of Purkinje and fastigial cells at P8, but loss of dopaminergic neurons was only detected in 90-day-old weavers and, therefore, vulnerability is built into this midbrain neural system during its late postnatal development. Our results show that depletion of Purkinje and fastigial cells is random with respect to the time of their birth, whereas the weaver gene seems to be specifically targeting the late-generated dopaminergic neurons.

Determination of the fraction of S-phase cells in root meristems using bromodeoxyuridine labeling.

The use of bromodeoxyuridine (BrdU) and subsequent immunocytochemical visualization for studying cell proliferation in plant meristems was investigated in Allium cepa L. root-tips. We describe the optimization of an indirect immunoperoxidase method for detecting incorporation of this DNA precursor in pulse-labeled cells. The basic object of this study is to quantify the extent to which the fraction of S-phase cells can reliably be estimated in asynchronous populations. A matrix of parallel labeling schedules with tritiated-thymidine or BrdU was developed, and the labeling indices provided by autoradiography or immunocytochemistry were compared. Thus, 0.5 mM BrdU assured saturation S-phase labeling after an exposure time of 30 min, and the mean length of the S-phase determined under such conditions was similar to that previously reported for this plant system. Interestingly, Feulgen staining did not interfere with subsequent detection of the BrdU probe. This allowed comparative evaluations of the nuclear DNA content by Feulgen-microdensitometry and the position of a given cell in G1, S or G2 compartments. We also explored the possibility of quantifying BrdU-incorporation in single nuclei by densitometry measurement of the peroxidase label.

Proliferative activity in the cerebellar external granular layer evaluated by bromodeoxyuridine labeling.

We have optimised an indirect immunoperoxidase technique demonstrating bromodeoxyuridine (BrdU) incorporation into dividing cells for cerebellar tissue sections of four-day-old rats injected with this marker. This permits confident identification of granule-cell precursors engaged in DNA synthesis in the external granular layer of the developing cerebellum. Preservation of BrdU immunoreactivity is attained using methanol/acetic acid fixation and different pretreatments before immunostaining, while unlabeled nuclei can be recognized clearly after Feulgen or hematoxylin counterstaining. We established conditions to ensure satisfactory BrdU uptake without affecting cell-cycle progression during the postlabeling time period. The dose of BrdU employed provides saturation S-phase labeling from at least 1 h after BrdU delivery. Various kinetic parameters and phase durations have been determined in experiments involving a single injection or cumulative labeling sequences, and the cycle time was calculated based on two models of generative behavior: steady-state and exponential growth. The working hypothesis of steady-state kinetics can be adopted successfully if the existence of neuroblasts with different proliferation rates is taken into account.

Evaluación de la respuesta de la Begonia Rex a la variación de medios y reguladores de crecimiento en técnicas de cultivo de hojas in vitro / Evaluation of the answer of the Begonia Rex to the variation of half irregular of growth in technical of cultivation of leaf in vitro

El presente trabajo comprendió la estandarización de tratamientos de desinfección, medios y reguladores de crecimiento, en el proceso de micropropagación de Begonia rex, especie con valor ornamental y de reproducción agámica, a partir de la técnica de cultivo in vitro de hojas y peciolos. Durante la etapa de desinfección, se probó los siguientes tratamientos con hipoclorito de sodio (obtenida a partir de lejía comercial): 1 por ciento de NaClO durante 10 min (para peciolo), 1,5 por ciento durante 20 min, 0.5 por ciento durante 45 min, 0.5 por ciento durante 10 min (para peciolos y hojas), 2 por ciento durante 15 min+0.5 por ciento durante 15 min y 0.5 por ciento durante 90 min (para hojas). Los resultados mostraron que, el tratamiento 0.5 por ciento de NaClO durante 45 min, es el más recomendado para la desinfección de hojas, y el tratamiento 1.5 por ciento durante 20 min para peciolos. Una vez establecido un método de desinfección, para hojas y peciolos, se procedió a evaluar los efectos de los medios de cultivo sobre los diferentes explantes (limbos foliares y peciolos). Se evaluaron los siguientes medios: (M1) MS sin reguladores de crecimiento; (M2) MS+0.1 mg/1 de ANA+0.4 mg/1 de BAP; (M3) MS+00.1 mg/1 de ANA+0.1 mg/1 de Kin (M4) MS+1 mg/1 de ANA+0.3 mg/1 de BAP; (M5) MS+0.5 mg/1 de AIB, resultando el más adecuado el M5 para peciolos y hojas, que indujo a la formación de mayor número de brotes en menor tiempo

Numeric simulation of plant signaling networks.

Plants have evolved an intricate signaling apparatus that integrates relevant information and allows an optimal response to environmental conditions. For instance, the coordination of defense responses against pathogens involves sophisticated molecular detection and communication systems. Multiple protection strategies may be deployed differentially by the plant according to the nature of the invading organism. These responses are also influenced by the environment, metabolism, and developmental stage of the plant. Though the cellular signaling processes traditionally have been described as linear sequences of events, it is now evident that they may be represented more accurately as network-like structures. The emerging paradigm can be represented readily with the use of Boolean language. This digital (numeric) formalism allows an accurate qualitative description of the signal transduction processes, and a dynamic representation through computer simulation. Moreover, it provides the required power to process the increasing amount of information emerging from the fields of genomics and proteomics, and from the use of new technologies such as microarray analysis. In this review, we have used the Boolean language to represent and analyze part of the signaling network of disease resistance in Arabidopsis.

Other Natural Hosts of Potato virus T.

Potato virus T (PVT), a member of the genus Trichovirus, was isolated from leaves of naturally infected ulluco (Ullucus tuberosus), oca (Oxalis tuberosa), and mashua (Tropaeolum tuberosum). These Andean tuber crops are often grown in small plots in association with potato (Solanum tuberosum) in the Peruvian highlands. PVT isolates from ulluco, oca, mashua, and potato infected virus-free ulluco, oca, and potato genotypes by mechanical inoculation. The incidence of PVT in mashua, oca, and ulluco accessions from the International Potato Center (CIP) in vitro germplasm bank was less than 10%. A polymerase chain reaction (PCR) product of approximately 330 bp was obtained from each of the four isolates using primers designed from the published PVT sequence. Restriction enzyme digestions of the PCR product did not demonstrate variability.

Progressive redistribution of alcohol dehydrogenase during vitellogenesis in Drosophila melanogaster: characterization of ADH-positive bodies in mature oocytes.

The use of monoclonal antibodies against Drosophila alcohol dehydrogenase (ADH) provides a powerful tool in the analysis of the tissue and temporal patterns of Adh gene expression. Immunocytochemical techniques at the light- and electron-microscopic levels have been used to determine the distribution of ADH in the ovarian follicles of D. melanogaster during oogenesis. In the early stages of oogenesis, small amounts of ADH are detectable in the cystocytes. At the beginning of vitellogenesis (S7), ADH appears to be located mainly in the nurse cells. From stage S9 onwards, the ADH protein is evenly distributed in the ooplasm until the later stages of oogenesis (S13-14), when multiple ADH-positive bodies of varying size appear in the ooplasm. This change in distribution is a result of the compartmentalization of the ADH protein within the glycogen yolk or beta-spheres. Yolk becomes enclosed within the lumen of the primitive gut during embryonic development, and thus our results suggest a mechanism for the transfer of maternally-inherited enzymes to the gut lumen via yolk spheres.

Developmental profile and tissue distribution of Drosophila alcohol dehydrogenase: an immunochemical analysis with monoclonal antibodies.

To analyze Drosophila alcohol dehydrogenase gene (Adh) expression and tissue distribution at various developmental stages, we devised several immunochemical techniques making use of monoclonal antibodies against Drosophila alcohol dehydrogenase (ADH), which had been obtained previously. We here report their application to analyze the expression of Adh in a wild-type strain of D. melanogaster. s-ELISA tests were performed to evaluate fluctuations in ADH content and specific activity during development in individual organs as well as in whole individuals. In all cases, ADH specific activity appeared to be quite constant, which implies that variations in enzyme activity reflect differences in protein content. Immunoblottings of crude homogenates revealed immunoreactive low relative molecular mass peptides in addition to the 27 KD monomeric band, showing a conserved banding pattern in different organs and developmental stages. Immunohistochemical assays on whole organs were used to analyze the general pattern of ADH distribution. Immunoperoxidase staining of cryosections proved to be of crucial relevance, as it yielded full details of the tissue localization of ADH within the ADH-positive organs. We have shown not only that ADH displays a specific distribution in some organs but also that the enzyme is restricted to certain cell types.