Mayor frecuencia de aberraciones cromosómicas en linfocitos expuestos o no a mitomicina C, de mujeres posmenopáusicas obesas en comparación con mujeres no obesas del departamento del Cauca, Colombia / High frequency of chromosome aberrations observed in lymphocytes in postmenopausal obese women

Introducción. Los estudios epidemiológicos indican que la obesidad está asociada en el 25 al 30 % con varios tipos de cáncer. Objetivo. Evaluar la frecuencia de aberraciones cromosómicas en linfocitos de mujeres posmenopáusicas obesas y no obesas, mediante la prueba de reto celular (challenge assay) como biomarcador de inestabilidad genómica. Materiales y métodos. Cuarenta mujeres posmenopáusicas fueron incluidas en el estudio (20 obesas y 20 no obesas). Los grupos fueron pareados según edad (± 5 años) y procedencia. Después de la firma voluntaria del consentimiento informado, las mujeres fueron entrevistadas y se les tomó una muestra de 5 ml de sangre periférica. Se establecieron cultivos de linfocitos con tratamiento con mitomicina C y sin él (prueba de reto celular) y, posteriormente, se registró la frecuencia de aberraciones cromosómicas para cada grupo y tratamiento. Resultados. En general, las mujeres obesas presentaron una mayor frecuencia de aberraciones cromosómicas en comparación con las no obesas. Después de exponer los cultivos celulares a mitomicina C, las mujeres obesas presentaron un incremento en el número de aberraciones cromosómicas totales en comparación con las no obesas (3,74±0,63 Vs. 2,70±0,61; p=0,001). Conclusiones. La mayor frecuencia de aberraciones cromosómicas en los linfocitos de mujeres posmenopáusicas obesas que en no obesas, sugiere diferencias en la capacidad de reparación del ADN, lo cual podría explicar la asociación entre la inestabilidad genómica y la mayor incidencia de cáncer en esta población.

Introduction. Epidemiological studies indicate that obesity is associated with an increased risk of 20-25% with several types of cancer. Objective. The frequency of chromosome aberrations was evaluated in lymphocytes from postmenopausal obese and non-obese women. Materials and methods. Twenty obese and 20 non-obese women, all post-menopause, were recruited. The groups were matched according to age (± 5 years) and place of origin. After signing the consent form, women were interviewed using a structured questionnaire, and a blood sample (5 ml) was drawn into vacutainer tubes. From each sample, lymphocyte cell cultures were established with and without mitomycin C (challenge assay). Afterwards, the frequency of chromosome aberrations were recorded for each group and treatment. Data were analyzed using the statistical program SPSS, v. 14.0. Results. Obese women had a higher frequency of chromosome aberrations when compared with non-obese women. After exposing the cell cultures to mitomycin C, obese women presented an increase in the number of total chromosome aberrations in comparison to non-obese women (3.7± 0.6 vs. 2.70±0.6; p=0.001). Conclusions. The higher frequency of chromosome aberrations in lymphocytes from postmenopausal obese women compared to non-obese women suggested differences in the DNA repair capacity. This may indicate an association between genomic instability and the higher incidence of cancer in this population.

Interacciones genotóxicas de mutágenos en mezclas binarias mediante ensayo cometa alcalino en linfocitos humanos / Interaction of mutagens in binary mixtures using the alkaline comet assay in human lymphocytes

Introducción. Los mutágenos contenidos en mezclas complejas presentan interacciones de sinergismo, aditivas o antagónicas. Se han desarrollado enfoques experimentales que permitan dilucidar el responsable de las interacciones en la mezcla. Objetivo. Desarrollar un diseño experimental para comprender los procesos que se llevan a cabo entre los compuestos presentes en las mezclas complejas. Materiales y métodos. Se expusieron linfocitos humanos a mezclas binarias de mutágenos B[a]P, DMBA, Trp-P-1 y MX durante una hora, con activación metabólica y sin ella. La viabilidad se evaluó con azul de tripano y, la genotoxicidad, con cometa alcalino. Resultados. Ningún hidrocarburo tuvo efecto con furanona. Con S9 y sin él, se observó que se presentaban interacciones tóxicas entre hidrocarburos. Se observó sinergismo sin S9 entre B[a]P y Trp-P-1 y, con actividad metabólica, entre DMBA y Trp-P-1. Sin S9 se observó interacción antagónica entre Trp-P-1 y DMBA y, con S9, entre Trp-P-1 y MX y entre MX y DMBA. Se observó un incremento dependiente de la dosis en la longitud de la cola. Hubo daño genotóxico medio y aumento de las células dañadas. Para todas las mezclas se pudo determinar la concentración mínima en la que se observaban efectos adversos y solo para algunas se determinó la concentración máxima en la cual no se observaron efectos adversos. Conclusión. Se hace un aporte para comprender los procesos que ocurren cuando en una mezcla hay presentes, al menos, dos mutágenos y se valida un modelo de análisis que permite dilucidar el compuesto que tiene efecto sobre otro. También, se demostró que según el tipo de compuestos en la mezcla, se tendrá o no un umbral de riesgo.

Introduction. Mutagens contained in complex mixtures can present synergistic interactions, either additive or antagonistic. Therefore, development of experimental approaches is necessary to elucidate which is the responsible agent for the effect in the mixtures. Objective. An experimental design was developed that allowed an understanding of the processes between the compounds of complex mixtures. Materials and methods. Human lymphocytes were exposed to binary mixtures of the mutagens B[a]P, DMBA, Trp-P-1 and MX for 1 hour with or without S9. Viability was assessed with trypan blue dye and the genotoxicity by the comet assay. Results. All of the hydrocarbon showed an effect with furanone. With and without S9, the most toxic interactions were observed between hydrocarbons. Synergistic interaction was observed without S9 between B [a] P and Trp-P-1 and between DMBA and Trp-P-1 with metabolic activity. Without S9 antagonistic interaction was observed only between Trp-P-1+DMBA, and with S9 between Trp-P-1+MX and MX+DMBA. It observed an increase dose dependent in tail length. Half the cultures showed genotoxic damage and increased cell damage. For each mixture, minimum concentrations were determined at which adverse effects are observed; for some only the maximum concentration was determined at which no adverse effects are observed. Conclusion. The processes between mutagens present in a mixture have become better understood, and the results validated an analytical model that determined which component had an effect on another. The results also showed that the type of compounds in the mixture determined whether or not a risk threshold was present.

[High frequency of chromosome aberrations observed in lymphocytes in postmenopausal obese women]. / Mayor frecuencia de aberraciones cromosómicas en linfocitos expuestos o no a mitomicina C, de mujeres posmenopáusicas obesas en comparación con mujeres no obesas del departamento del Cauca, Colombia.

INTRODUCTION: Epidemiological studies indicate that obesity is associated with an increased risk of 20-25% with several types of cancer. OBJECTIVE: The frequency of chromosome aberrations was evaluated in lymphocytes from postmenopausal obese and non-obese women. MATERIALS AND METHODS: Twenty obese and 20 non-obese women, all post-menopause, were recruited. The groups were matched according to age (± 5 years) and place of origin. After signing the consent form, women were interviewed using a structured questionnaire, and a blood sample (5 ml) was drawn into vacutainer tubes. From each sample, lymphocyte cell cultures were established with and without mitomycin C (challenge assay). Afterwards, the frequency of chromosome aberrations were recorded for each group and treatment. Data were analyzed using the statistical program SPSS, v. 14.0. RESULTS: Obese women had a higher frequency of chromosome aberrations when compared with non-obese women. After exposing the cell cultures to mitomycin C, obese women presented an increase in the number of total chromosome aberrations in comparison to non-obese women (3.7± 0.6 vs. 2.70±0.6; p=0.001). CONCLUSIONS: The higher frequency of chromosome aberrations in lymphocytes from postmenopausal obese women compared to non-obese women suggested differences in the DNA repair capacity. This may indicate an association between genomic instability and the higher incidence of cancer in this population.

[Interaction of mutagens in binary mixtures using the alkaline comet assay in human lymphocytes]. / Interacciones genotóxicas de mutágenos en mezclas binarias mediante ensayo cometa alcalino en linfocitos humanos.

INTRODUCTION: Mutagens contained in complex mixtures can present synergistic interactions, either additive or antagonistic. Therefore, development of experimental approaches is necessary to elucidate which is the responsible agent for the effect in the mixtures. OBJECTIVE: An experimental design was developed that allowed an understanding of the processes between the compounds of complex mixtures. MATERIALS AND METHODS: Human lymphocytes were exposed to binary mixtures of the mutagens B[a]P, DMBA, Trp-P-1 and MX for 1 hour with or without S9. Viability was assessed with trypan blue dye and the genotoxicity by the comet assay. RESULTS: All of the hydrocarbon showed an effect with furanone. With and without S9, the most toxic interactions were observed between hydrocarbons. Synergistic interaction was observed without S9 between B [a] P and Trp-P-1 and between DMBA and Trp-P-1 with metabolic activity. Without S9 antagonistic interaction was observed only between Trp-P-1+DMBA, and with S9 between Trp-P-1+MX and MX+DMBA. It observed an increase dose dependent in tail length. Half the cultures showed genotoxic damage and increased cell damage. For each mixture, minimum concentrations were determined at which adverse effects are observed; for some only the maximum concentration was determined at which no adverse effects are observed. CONCLUSION: The processes between mutagens present in a mixture have become better understood, and the results validated an analytical model that determined which component had an effect on another. The results also showed that the type of compounds in the mixture determined whether or not a risk threshold was present.

Gene expression in SK-Mel-28 human melanoma cells treated with thesnake venom jararhagin

Alternative approaches to improve the treatment of advanced melanomas are highly needed.The disintegrin domain of metalloproteinases binds integrin receptors on tumor cells,blocking migration, invasion, and metastatization. Previous studies showed that jararhagin,from the Bothrops jararaca snake venom, induces changes in the morphology and viability ofSK-Mel-28 human melanoma cells, and decreases the number of metastases in mice injected with pre-treated cells. The purpose of this study was to evaluate the molecular effects ofjararhagin on SK-Mel-28 cells and fibroblasts, concerning the expression of integrins, cadherins, caspases, and TP53 genes. Sub-toxic doses of jararhagin were administered to confluent cells. RT-PCR was performed following extraction of total RNA. Jararhagin treatmentsinduced similar morphological alterations in both normal and tumor cells, with higher IC50 values for fibroblasts. Integrin genes were downregulated in untreated cells,except for ITGA6a,b, ITGAv, and ITGB3 which were highly expressed in SK-Mel-28. The integrin expression profiles were not affected by the toxin. However, jararhagin 30 ng/mlupregulated genes TP53, CDKN1A, CDKN2A, CASP3, CASP5, CASP6, CASP8, and E-CDH in SKMel-28, and genes ITGB6, ITGB7, CASP3, TP53, and CDKN1B in fibroblasts. Appropriate jararhagin concentration can have apoptotic and suppressant effects on SK-Mel-28 cells, ratherthan on fibroblasts, and can be used to develop potential anti-cancer drugs.

Cytogenetic aberrations in primary cell cultures of the ovarian surface epithelium / Aberraciones citogenéticas en cultivos primarios del epitelio superficial del ovario

Our objective was to determine the presence of chromosomal abnormalities in primary cultures of ovarian surface epithelial cells in women of different ages with no history of cancer. Throughout conventional cytogenetic techniques, we analyzed chromosome spreads of cultured ovarian epithelial cells from 10 donors who were 50 or more years old (B) and 16 controls between 20 and 49 years old (A), belonging to the mestizo population in Bogota DC, Colombia. Of the 26 cultures that were analyzed in passage 1, 61.5% had an abnormal chromosome complement (62.5% in A, and 60% in B). Abnormalities included polyploidies, endoduplications and monosomies. Deletions in chromosomes 3 and 11 were found in just one metaphase. None of the samples showed weaknesses or breakpoints. After transforming and applying the exact student’s t-test for variance heterogeneity, we found significant differences in the frequency of metaphases, that were higher in A than in B (p=0.05), and in the frequency of polyploidies, which were higher in B than in A (p=0.044). Through the application of the Mann-Whitney test, we determined that the frequency of endoduplications was higher in A than in B (p=0.126), without reaching significant differences. There were no significant differences in the frequency of monosomies. The level of significance was set at p £ 0.05. Taking into account that polyploidization is a marker of chromosomal instability and that the risk of cancer arising from the ovarian surface epithelium augments substantially after menopause, the increase in the frequency of age-associated polyploidies could be used as a predictor of ovarian cancer in women from an ethnically homogeneous population as the mestizo one in Bogota DC.

El objetivo del presente trabajo fue determinar la presencia de anormalidades cromosómicas en cultivos primarios de células del epitelio superficial ovárico en mujeres de diferentes edades, sin antecedentes de cáncer. Mediante técnicas de citogenética convencional fueron analizados extendidos de células epiteliales ováricas histológicamente normales, provenientes de cultivos primarios de 10 donantes de 50 o más años (B) y de 16 donantes entre 20 y 49 años que se utilizaron como grupo control (A), pertenecientes a la población mestiza de Bogotá DC, Colombia. De 26 cultivos examinados en pase 1, 61,5% presentó complemento cromosómico anormal, 62,5% en A y 60% en B. Las anomalías numéricas halladas, todas en mosaico, incluyeron poliploidías, endoduplicaciones y monosomías. En una única célula en metafase de un cultivo, se presentaron deleciones en los cromosomas 3 y 11. Ninguna muestra presentó fragilidades o roturas. Previa aplicación de transformaciones, con la prueba exacta t-student para varianzas heterogéneas, se encontraron diferencias significativas en la frecuencia de células con metafase normal, mayor en A que en B (p=0,05) y en la de poliploidías, mayor en B que en A (p=0,044). Con la prueba exacta de Mann-Whitney se determinó que la frecuencia de endoduplicaciones en A fue mayor que en B (p=0,126), sin alcanzar diferencias significativas y que no hubo diferencias significativas en la frecuencia de monosomías. El nivel de significación fue p £ 0,05. Si se tiene en cuenta que la poliploidización es un marcador de inestabilidad cromosómica y, que además, el riesgo de aparición de cáncer derivado del epitelio superficial del ovario aumenta sustancialmente después de la menopausia, el incremento en la frecuencia de poliploidías asociado con la edad podría ser utilizado como predictor de cáncer ovárico en mujeres de una población étnicamente homogénea como la población mestiza de Bogotá DC.

Cytogenetic aberrations in primary cell cultures of the ovarian surface epithelium.

Our objective was to determine the presence of chromosomal abnormalities in primary cultures of ovarian surface epithelial cells in women of different ages with no history of cancer. Throughout conventional cytogenetic techniques, we analyzed chromosome spreads of cultured ovarian epithelial cells from 10 donors who were 50 or more years old (B) and 16 controls between 20 and 49 years old (A), belonging to the mestizo population in Bogota DC, Colombia. Of the 26 cultures that were analyzed in passage 1, 61.5% had an abnormal chromosome complement (62.5% in A, and 60% in B). Abnormalities included polyploidies, endoduplications and monosomies. Deletions in chromosomes 3 and 11 were found in just one metaphase. None of the samples showed weaknesses or breakpoints. After transforming and applying the exact student's t-test for variance heterogeneity, we found significant differences in the frequency of metaphases, that were higher in A than in B (p=0.05), and in the frequency of polyploidies, which were higher in B than in A (p=0.044). Through the application of the Mann-Whitney test, we determined that the frequency of endoduplications was higher in A than in B (p=0.126), without reaching significant differences. There were no significant differences in the frequency of monosomies. The level of significance was set at p < or = 0.05. Taking into account that polyploidization is a marker of chromosomal instability and that the risk of cancer arising from the ovarian surface epithelium augments substantially after menopause, the increase in the frequency of age-associated polyploidies could be used as a predictor of ovarian cancer in women from an ethnically homogeneous population as the mestizo one in Bogota DC.

Schwann cell chondroitin sulfate proteoglycan inhibits dorsal root ganglion neuron neurite outgrowth and substrate specificity via a soma and not a growth cone mechanism.

Sensory axons do not regenerate into or within the spinal cord because of the presence of the axon regeneration inhibitor chondroitin sulfate proteoglycan (CSPG) on activated astrocytes. In the peripheral nervous system, CSPG associated with denervated Schwann cells retards axon regeneration, but regeneration occurs because the balance of regenerating, inhibiting, and promoting factors favors regeneration. The present experiments were aimed at determining the mechanism by which Schwann cells inhibit adult human dorsal root ganglia (H-DRG) neuron growth cone elongation and substrate specificity, restricting the growth cones to Schwann cell membranes and inhibiting their growth onto a poly-l-lysine/laminin substrate. Neurites of H-DRG neurons free of soma contact with Schwann cells, or after the Schwann cell membranes' CSPG had been digested, were 11.1-fold longer than those of neurons in soma contact with untreated Schwann cells. Growth cones of DRG neuron somas without Schwann cell CSPG showed no outgrowth inhibition or substrate specificity. These results indicate that the Schwann cell CSPG influences act via contact with neuron somas but not growth cones. These results suggest that eliminating CSPG associated with Schwann cells within DRG in vivo will make the neurons' growth cones insensitive to the regeneration inhibitory influences of CSPG, allowing them to regenerate through the dorsal root entry zone and into and within the spinal cord, where they can establish appropriate and functional synaptic connections.

Cytological indications of the complex subtelomeric structure.

Research on the subtelomeric region has considerably increased because this chromosome segment (1) keeps the chromosome number constant, (2) intervenes in cancer and cell senescence processes, (3) presents more crossovers than other regions of the genome and, (4) is the site of cryptic chromosome aberrations associated with mental retardation and congenital malformations. Quantitative microphotometrical scanning and computer graphic image analysis enables the detection of differentially distributed Giemsa-stained structures in T-banded subtelomeric segments of human and Chinese hamster ovary (CHO) chromosomes. The presence of high density stain patterns in the subtelomeric region was confirmed using endoreduplicated chromosomes as a model. Besides, prolonging the incubation in the T-buffer, specific holes were induced in subtelomeric segments. Hole specificity was confirmed inducing them in complex CHO chromosome aberrations obtained by AluI. The method was also used to detect minute sister chromatid exchanges in the T-banded subtelomeric area (t-SCEs). The presence of t-SCEs was suspected to reflect, at the microscope level, the high crossover activity prevailing in the region. Due to the fact that the fluorescent signals obtained with subtelomeric probes seem to be colocalized with subtelomeric high density areas, measurements on the position of both structures with respect to the diffraction and chromosome edges were carried out. Data obtained showed comparable values suggesting that the high density segments were located where telomeric probes usually fluoresce. The possible relationship of the high density patterns, the production of specific holes, the localization of fluorescent areas and the detection of minute SCEs in the subtelomeric segment observed in T-banded CHO and human chromosomes is briefly reviewed.

Analysis of ETV6/RUNX1 fusions for evaluating the late effects of cancer therapy in ALL (acute lymphoblastic leukemia) cured patients.

Acute Lymphoblastic Leukemia (ALL) is the most common malignancy in childhood. The improvements of therapies have increased the number of long-term survivors. However, an increased incidence of secondary neoplasias has been observed in this cohort. Our purpose was to evaluate the late effects of cancer therapy in cured patients previously treated for ALL, considering previous reports on the occurrence of gene fusions as putative markers of chromosomal instability. Twelve ALL patients (aged 5 to 16 years) and twelve healthy subjects (aged 18 to 22 years) were studied for the presence of ETV6/RUNX1 (TEL/AML1) translocations, which were detected by FISH (fluorescence in situ hybridization). The blood samples were collected months or years after completion of the therapy, and the frequencies of gene fusions in lymphocytes were compared with those obtained retrospectively for bone marrow samples at the time of diagnosis, and also for the control group. It was demonstrated that ETV6/RUNX1 gene fusion was a frequent event (0.59-1.84/100 cells) in peripheral blood lymphocytes from normal individuals and the ALL patients who underwent chemotherapy showed significantly (P = 0.0043) increased frequencies (0.62-3.96/100 cells) of the rearrangement when compared with the control groups (patients at diagnosis and healthy subjects). However, a significant difference was not found between the groups of patients at diagnosis and healthy subjects, when the two patients who were positive for the rearrangement were excluded. Therefore, increased frequencies of ETV6/RUNX1 fusions in ALL cured patients indicate the influence of previous exposure to anti-cancer drugs, and they may represent an important genetic marker for estimating the risk of relapse, or development of secondary neoplasias.

Morphogenesis in short-term and long-term anther derived calli of Oenothera hookeri de vries

Anther culture of O. hookeri on Murashige and Skoog (1962) medium supplemented with 2 mg l-1 2,4-dichlorophenoxyacetic acid and 2 mg-1 1-naphthaleneacetic acid produced callus formation. When subcultured onto medium lacking auxin, the callus regenerated through the organogenic pathway. Non-organogenic and organogenic callus was observed using histological methods after 2, 3 and 24 weeks in culture. Three types of calli were recognized: non-organogenic friable calli, organogenic friable calli with roots and organogenic hard calli with shoots. The microscopical sections showed striking differences in tissue organization among friable and compact calli. Vascular bundles were prominent in compact calli, but were not found in friable calli. Calli sections showed at light microscopy cells at two developmental stages; differentiated highly vacuolated cells and meristematic small isodiametric cells with densely stained cytoplasm. At electron microscopy level abnormal chloroplasts were present in non-organogenic calli, while chloroplasts were well developed in organogenic hard calli. Peroxisomes with paracrystalline protein bodies were abundant in both types of calli.

Morphogenesis in short-term and long-term anther derived calli of Oenothera hookeri de vries

Anther culture of O. hookeri on Murashige and Skoog (1962) medium supplemented with 2 mg l-1 2,4-dichlorophenoxyacetic acid and 2 mg-1 1-naphthaleneacetic acid produced callus formation. When subcultured onto medium lacking auxin, the callus regenerated through the organogenic pathway. Non-organogenic and organogenic callus was observed using histological methods after 2, 3 and 24 weeks in culture. Three types of calli were recognized: non-organogenic friable calli, organogenic friable calli with roots and organogenic hard calli with shoots. The microscopical sections showed striking differences in tissue organization among friable and compact calli. Vascular bundles were prominent in compact calli, but were not found in friable calli. Calli sections showed at light microscopy cells at two developmental stages; differentiated highly vacuolated cells and meristematic small isodiametric cells with densely stained cytoplasm. At electron microscopy level abnormal chloroplasts were present in non-organogenic calli, while chloroplasts were well developed in organogenic hard calli. Peroxisomes with paracrystalline protein bodies were abundant in both types of calli.(AU)

Morphogenesis in short-term and long-term anther derived calli of Oenothera hookeri de vries.

Anther culture of O. hookeri on Murashige and Skoog (1962) medium supplemented with 2 mg l-1 2,4-dichlorophenoxyacetic acid and 2 mg-1 1-naphthaleneacetic acid produced callus formation. When subcultured onto medium lacking auxin, the callus regenerated through the organogenic pathway. Non-organogenic and organogenic callus was observed using histological methods after 2, 3 and 24 weeks in culture. Three types of calli were recognized: non-organogenic friable calli, organogenic friable calli with roots and organogenic hard calli with shoots. The microscopical sections showed striking differences in tissue organization among friable and compact calli. Vascular bundles were prominent in compact calli, but were not found in friable calli. Calli sections showed at light microscopy cells at two developmental stages; differentiated highly vacuolated cells and meristematic small isodiametric cells with densely stained cytoplasm. At electron microscopy level abnormal chloroplasts were present in non-organogenic calli, while chloroplasts were well developed in organogenic hard calli. Peroxisomes with paracrystalline protein bodies were abundant in both types of calli.

Ensayo de la proliferación celular en cultivo de linfocitos de cerdo / Assay kinetics cell proliferations lymphocytes from pigs

Se reporta el cultivo de linfocitos de sangre periférica completa de cerdos sanos e infectados, para evaluar la cinética de proliferación celular; 0.5 ml de sangre fue cultivada en 6.0 ml de RPMI-11640 suplementado, en presencia de fitohemaglutinina y 5-BrdU, a 37§C. Al cabo de 48 horas de incubación se cosecharon y fueron teñidos de acuerdo a la técnica de fluorescencia más Giemsa, obteniéndose así células en diferentes etapas de diferenciación, identificándolas en primera, segunda y tercera división. La actividad proliferativa se midió bajo dos parámetros: índice mitótico e índice de replicación. Los resultados son reproducibles y se pueden diferenciar los efectos citotóxicos de los citostáticos sobre los linfocitos del huésped

Estimulación de la proliferación de las células de leucemia aguda linfoblástica en cultivo / Stimulation of acute lymphoblastic leukemia cell proliferation in cell cultures

Para conocer los estimulantes mitógenos más adecuados para la iniciación de la actividad mitótica de los blastos se utilizaronultivos de 20 muestras de células de leucemia aguda linfoblástica (LAL). Se analizaron diferentes concentraciones de fitohemaglutinina (PHA), lectina (Phitolacca americana) (FL) y 2-mercaptoetanol (2-ME) mediante la estimulación de cultivos celulares de 20 muestras. La mucoproteina extraída de las plantas (PHA) resultó ser el mejor activador de la mitosis y de la proliferación. A una concentración de 2.5 mg/ml, ocurrió la división celular; en su ausencia, no se observó proliferación celular. Por otra parte, la FL tuvo un efecto menor de la activación de la mitosis en los cultivos; y el 2-ME no presentó efecto alguno sobre la proliferación de estas células. Además, se observó que la acción mitogénica de la PHA implica la activación de la replicación del ADN celular, tal y como lo demostró la incorporación de [3H]-timidina

Localización con inmunoperoxidasa de antígenos rábicos en la superficie celular en cultivos celulares infectados a baja multiplicidad / Immunoperoxidase cell surface localization of rabies virus antigen in tissue cultures at a low viral multiplicity

Con el propósito de observar los antígenos del virus rábico en cultivos celulares se utilizaron las inmunoglobulinas provenientes de una yegua hiperinmunizada, se acoplaron los anticuerpos antivirus rábico a peroxidasa tipo VI, se incubaron con células 13 SCL infectadas con virus rábico a las 24, 48 y 72 horas, y se oservaron a los microscopios de luz y electrónico. Con el primero no se vieron sitios de reconocimiento de antígeno; sin embargo, con el microscopio electrónico fue posible observar el precipitado del complejo de inmunoperoxidasa en la superficie de los virus y de la membrana celular de células infectadas. El sistema permite evaluar cuantitativamente y con resolución ultraestructural los sitios de reconocimiento de superficie de antígenos del virus rábico

Production of plasminogen activator in a melanoma cell line.

A melanoma cell line (Bowes) was found to produce plasminogen activator even on its growing phase, and the rate of plasminogen activator production was rather constant. The production of plasminogen activator was proportional to the cell number. Morphologically, no specific features for plasminogen activator production were seen. Plasminogen activator was observed in the lysate of this cell line only when the cell number was large. The extracellular plasminogen activator activity was higher than the intracellular plasminogen activator activity, suggesting the existence of a secretion mechanism for the plasminogen activator.

[Isolation of bovine cell lines and susceptibility to foot-and-mouth disease virus]. / Isolamento de linhagens celulares bovinas e suscetibilidade ao vírus da febre aftosa.

Morphology and chromosomes of cell sublines derived from two new bovine kidney lines are reported. Cell susceptibility to the foot-and-mouth disease virus is discussed. One of the sublines showed epithelial-like cells, while the remainder, elonged fibroblastic-like cells. Most of them had a diploid number of chromosomes. From these sublines only one was sensible to the foot-and-mouth disease virus.

[Ultrastructural aspects of Parthenocissus tricuspidata (Planch.) (Vitaceae) "callus" kept in solid cultures (author's transl)]. / Estudo preliminar da ultraestrutura de tecidos de "callus" de Parthenocissus tricuspidata (Planch), (Vitceae) mantidos em cultura.

The normal strain shows undifferentiated chloroplasts in opposition to the very well chlorophyllated "callus" which shows all the normal ultrastructural characteristics of the various organelles. The strain which has lost completely the capacity of chlorophyl synthesis shows a remarkable increase in the size and number of mitochondria. The tumor tissue shows deep lobulation in its nuclei as well as undifferentiated plastids in the cytoplasm. An increase of the smooth endoplasmic reticulum in the tumor tissue was also observed.