Actividad citotóxica de physalis peruviana (aguaymanto) en cultivos celulares de adenocarcinoma colorectal, próstata y leucemia mieloide crónica / Cytotoxic effect of physalis peruviana in cell culture of colorectal and prostate cancer and chronic myeloid leukemia

INTRODUCCIÓN: Las plantas han sido empleadas como drogas por siglos. Sin embargo, se ha investigado poco sobre su gran potencial como fuentes de nuevos agentes terapéuticos. El objetivo del presente trabajo fue evaluar la actividad citotóxica de los extractos etanólicos de tallos y hojas de Physalis peruviana, sobre las líneas celulares HT-29, PC-3, K-562 y VERO. MATERIALES Y MÉTODOS: Las líneas celulares HT-29, PC-3, K-562 y VERO, fueron expuestas a cuatro concentraciones de extractos etanólicos de tallos y hojas de Physalis peruviana. Asimismo, a diferentes concentraciones de cisplatino y 5-Fluorouracilo (5-FU), que se usaron como controles positivos. Se hallaron los porcentajes de crecimiento en 48 horas, luego se determinó la concentración inhibitoria 50 (IC50) mediante análisis de regresión lineal y el índice de selectividad de cada muestra. RESULTADOS: Los extractos etanólicos de tallos y hojas de Physalis peruviana mostraron actividad citotóxica: Los CI50 en μg/mL en hojas y tallos fueron, 0.35 (r=-0.95 p<0.025) y 0.37 (r=-0,90 p<0.05) para HT-29; 0.87 (r=-0.98 p<0.01) y 1.01 (r=-0.95 p<0.025) para PC-3; 0.02 (r=-0.98 p<0.01) y 0.03 (r=-0.98 p<0.01) para K-562; 4.9 (r=-0.95 p<0.025) y 6.2 (r=-0.98 p<0.01) para VERO. Los CI50 para los antineoplásicos fueron: para el cisplatino: 4.2 (r=-0.96 p<0.025), 10.3 (r=-0.97 p<0.025), 0.15 (r=-0.98 p=0.01), y 1.1 (r=-0.98 p=0.01). Parael 5-FU: 2.3 (r=-0.97 p<0.025), 17.9 (r=-0.95 p<0.025), 0.15 (r=-0.98 p=0.01), y 1.1 (r=-0.94 p=0.05) para HT-29, PC-3, K562 y VERO, respectivamente. Los índices de selectividad de los extractos de tallos y hojas, estuvieron entre 5.6 y 245 para las líneas celulares tumorales evaluadas; por el contrario, el cisplatino y el 5-FU, solo alcanzaron valores entre 0.11 y 7.3...

INTRODUCTION: The plants have been used as drugs for centuries. However, limited research has been done on its great potential as sources of new therapeutic agents. The purpose of this study was to evaluate Physalis peruviana cytotoxic activity on cell lines HT-29, PC-3, K-562 and VERO. Materials and Methods: The HT-29 cell lines, PC-3, K-562 and VERO, were exposed to four concentrations of P. peruviana ethanolic leave and stem extracts, also at different concentrations of cisplatin and 5-fluorouracil (5-FU), which were used as positive controls. We found rates of growth within 48 hours, then we determined the inhibitory concentration 50 (IC50) using linear regression analysis and the index of selectivity of each sample. RESULTS: The P. peruviana ethanolic leave and stem extracts showed cytotoxic activity. The IC50 in μg/mL in leaves and stems were, 0.35 (r =-0.95 p <0.025) and 0.37 (r =- 0.90 p <0.05 ) for HT-29; 0.87 (r =-0.98 p <0.01) and 1.01 (r =-0.95 p <0.025) for PC-3; 0.02 (r =-0.98p <0.01) and 0.03 (r =-0.98 p <0.01) for K-562; 4.9 (r =-0.95 p <0.025) and 6.2 (r =-0.98 p <0.01) for VERO. The IC50 for antineoplastic were: for cisplatin: 4.2 (r =-0.96 p <0.025),10.3 (r =-0.97 p <0.025), 0.15 (r =-0.98 p = 0.01) and 1.1 (r =- 0.98 p = 0.01); for 5-FU: 2.3 (r =-0.97 p <0.025), 17.9 (r =-0.95 p <0.025), 0.15 (r =-0.98 p = 0.01) and 1.1 (r =-0.94 p = 0.05) for HT-29, PC-3, K562 and VERO respectively. The leaves and stems extracts selectivity index were between 5.6 and 245 for tumor cell lines evaluated, by contrast, cisplatin and 5-FU, only showed values between 0.11 and 7.3. CONCLUSIONS: The P. peruviana leaves and steams ethanolic extracts were more cytotoxic than cisplatin and 5 FU, on the lines HT-29, PC-3 and K562. Furthermore the P. peruviana cytotoxic effects were less than cisplatin and 5-FU for VERO control cells lines.

Cytotoxicity of endodontic irrigants containing calcium hydroxide and sodium lauryl sulphate on fibroblasts derived from mouse L929 cell line

The aim of this study was to evaluate the cytotoxicity of root canal irrigating solutions containing calcium hydroxide and sodium lauryl sulphate on fibroblasts derived from L929 cell line. Saturated calcium hydroxide aqueous solution (CH), sodium lauryl sulphate (SLS) and SLS associated with calcium hydroxide (HCT20) were diluted with sterile distilled water at 50 percent, 20 percent, 10 percent and 5 percent concentrations. Minimum essential medium (MEM) served as the control group. The cytotoxicity of the solutions was evaluated on L929 mouse fibroblast cell line, at 4 and 24 h of contact time by the 51Cr radiotracer method. Data were compared and statistical inferences were made with the chi-square test. In all analysis, significance level was set at 5 percent. CH and HCT20 showed toxicity at 50 percent concentration, while at concentrations lower than 50 percent these solutions showed cell tolerance. SLS was cytotoxic at all concentrations. In conclusion, the association of calcium hydroxide and SLS (HCT20) combines the beneficial properties of these solutions and was not harmful to the fibroblast cell line, seeming to be a suitable endodontic irrigating solution.

O objetivo desta pesquisa foi avaliar a citotoxicidade de soluções irrigadoras de canais radiculares contendo hidróxido de cálcio e lauril sulfato de sódio em linhagem de fibroblastos L929. Solução aquosa saturada de hidróxido de cálcio, lauril sulfato de sódio e HCT20 (lauril sulfato de sódio e hidróxido de cálcio) foram diluídos em água destilada em concentrações de 50 por cento, 20 por cento, 10 por cento e 5 por cento. O grupo controle foi representado por meio de cultura de células (MEM - minimum essential medium). A citotoxicidade das soluções sobre os fibroblastos foi avaliada em 4 e 24 h de contato, pelo método do cromo radioativo. Os resultados foram analisados estatisticamente pelo teste do qui-quadrado. Em todas as análises, o intervalo de confiança referente às médias entre os grupos foi estabelecido em 95 por cento. As soluções saturadas de hidróxido de cálcio e o HCT20 apresentaram toxicidade nas concentrações de 50 por cento. O lauril sulfato de sódio foi tóxico em todas as concentrações. As soluções de hidróxido de cálcio em concentrações menores que 50 por cento apresentaram tolerância celular, assim como combinadas ao lauril sulfato de sódio. Tal comportamento não foi observado na solução pura de lauril sulfato de sódio em todas as concentrações.

L929 cell response to root perforation repair cements: an in vitro cytotoxicity assay

This study compared the cytotoxicity of an experimental epoxy-resin and calcium hydroxide-based cement (MBPc), gray mineral trioxide aggregate (MTA) and white mineral trioxide aggregate (WMTA) using the agar overlay method with neutral red dye. L929 cells were seeded into 6-well culture plates where 48-h set test materials were placed on the agar overlay, in triplicate. Teflon and natural rubber served as negative and positive controls. After an incubation period of 24 h at 37ºC in a humidified atmosphere of 5 percent CO2 in air, a discolored area around the samples and the positive controls could be observed and measured per quadrant. The mean values were compared and converted into grades to classify the results according to the table of cytotoxicity grades according to the Standard Operating Procedures (SOP) of the Oswaldo Cruz Foundation, Brazil. The nonviable cell areas and the morphological changes in the cells were observed with an inverted microscope. The results showed grade 1 (slight) for the two types of MTA (p>0.05) and grade 2 (mild) for the MBPc (p<0.001). All samples met the requirements of the test as none of the cultures showed reactivity higher than grade 2.

O objetivo deste estudo foi comparar a citotoxicidade de um cimento experimental à base de resina epóxica e hidróxido de cálcio (MBPc), do agregado trióxido mineral (MTA) cinza e do MTA branco, utilizando o ensaio de difusão em agar com o corante vermelho neutro. Células L929 foram semeadas em placas de 6 poços e sobre elas a camada de agar, onde foram colocados os materiais endurecidos por 48 h, em triplicata, além de teflon como controle negativo e látex como controle positivo. Após 24 h em estufa umidificada a 37ºC com 5 por cento CO2, um halo claro se formou ao redor das amostras e dos controles positivos. As medidas foram tomadas, por quadrante, e as médias foram comparadas e convertidas em graus para qualificar os resultados, de acordo com a tabela de grau de citotoxicidade do POP/FIOCRUZ. As zonas de inibição e as alterações da morfologia celular foram avaliadas sob microscópio invertido. Os resultados revelaram grau 1 (leve) para os dois tipos de MTA (p>0,05) e grau 2 (branda) para o MBPc (p<0,001). Todas as amostras foram consideradas satisfatórias, pois nenhuma cultura exposta aos cimentos revelou toxicidade superior ao grau 2.

Effects of different dental alloys on cytotoxic and apoptosis related genes expression of mouse fibroblast cells L929 / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate effects of the leaching liquids of 5 different kinds of dental alloys on L929 cells at cell level and molecular level.</p><p><b>METHODS</b>The fibroblast L929 cells of mouse were cultivated in vitro in leaching liquids of 5 different kinds of dental alloys, Au alloy (n = 8), Ag-Pt alloy (n = 8), Co-Cr alloy (n = 8), Ni-Cr alloy (n = 8), and Cu alloy (n = 8). The RPMI 1640 cell medium containing 10% fetal beef serum was used as control. The cytotoxicities of the 5 dental alloys were evaluated by means of methyl thiazolyl tetrazolium (MTT), and the effects of these alloys on the expression of caspase-3, caspase-8, and caspase-9 mRNA of L929 cells were examined using reverse transcription polymerase chain reaction (RT-PCR) method.</p><p><b>RESULTS</b>After 48 hours culture the cytotoxicity of Cu alloy group was in Grade 4 and those of the other groups were all in Grade 0. The mRNA levels of caspase-8 had no change in all groups (P > 0.05). The mRNA levels of caspase-3 were as follows: Cu alloy (0.474 +/- 0.001), the negative control (0.527 +/- 0.003), Au alloy (0.528 +/- 0.013), Co-Cr alloy (0.615 +/- 0.007), Ag-Pd alloy (0.673 +/- 0.009), and Ni-Cr alloy (0.803 +/- 0.037). The mRNA levels of caspase-9 were as follows: Cu alloy (0.532 +/- 0.041), Au alloy (0.574 +/- 0.013), the negative control (0.578 +/- 0.010), Co-Cr alloy (0.617 +/- 0.009), Ag-Pd alloy (0.703 +/- 0.018), and Ni-Cr alloy (0.811 +/- 0.037). There were significant differences between the groups except the negative control group and Au alloy group.</p><p><b>CONCLUSIONS</b>The Cu alloy shows the highest cytotoxicity, and the leaching liquids of 5 different kinds of dental alloys may induce cell apoptosis through mitochondrion pathway.</p>

Comparative study of the cytotoxic effect of resilon against two cell lines

Resilon is a new material that is a candidate to replace gutta-percha as a root filling material. This study evaluated the antiproliferative effect of Resilon and two commercially available gutta-percha points (Roeko, Dentsply). Two established cell lines (L929 and RPC-C2A) were used for the experiment. Cell survival fraction was estimated by the sulforhodamine-B assay, in reference to controls after 48-h exposure. Non-parametric tests (Kruskal-Wallis followed by Dunn's multiple comparisons) were used to evaluate the statistical significance of the results (α=0.05). Cytotoxicity in a descending order was: Resilon > Roeko gutta-percha > Dentsply gutta-percha. At 24-h exposure, no statistically significant differences (p>0.05) were observed between tested materials in both cell lines. At 48-h exposure, statistically significant differences (p<0.05) were found between Resilon and the other materials in the L929 cell line. In the RPC-C2A cell line Resilon was significantly more cytotoxic than Dentsply gutta-percha (p<0.05), but no statistically significant differences (p>0.05) were found between Resilon and Roeko gutta-percha. The cytotoxicity of Resilon increased significantly from 24 h to 48 h in both cell lines. Resilon points were more cytotoxic than gutta-percha points. The cytotoxicity was time dependent and increased after 48 h.

Resilon é um material novo com potencial para substituir a guta-percha como material obturador radicular. Este estudo avaliou o efeito anti-proliferativo do Resilon e de duas marcas comerciais de pontas de guta-percha (Roeko e Dentsply). Para os fins deste estudo foram utilizadas duas linhagens celulares conhecidas (L929 e RPC-C2A). A fração de sobrevivência celular foi estimada pelo método colorimétrico de sulforodamina B comparado aos controles após exposição por 48 h. A significância estatística dos resultados (α=0,05) foi avaliada pelos testes não-paramétricos de Kruskal-Wallis e Dunn para comparações múltiplas. A citotoxicidade dos materiais em ordem decrescente foi: Resilon > guta-percha Roeko > guta-percha Dentsply. Após 24 h de exposição, não foram encontradas diferenças estatisticamente significantes (p>0,05) entre os materiais testados em ambas as linhagens celulares. Após 48 h, o Resilon apresentou um efeito citotóxico significantemente maior (p<0,05) em comparação aos outros dois materiais na linhagem celular L929. Na linhagem RPC-C2A, a citotoxicidade do Resilon foi significantemente maior (p<0,05) que a da guta-percha Dentsply, mas não houve diferenças significantes (p<0,05) entre Resilon e guta-percha Roeko. A citotoxicidade do Resilon aumentou significativamente de 24 para 48 h para ambas as linhagens celulares. As pontas de Resilon foram mais citotóxicas do que as pontas de guta-percha. A citotoxicidade foi tempo-dependente e aumentou após 48 h de exposição.

Citotoxicidad de un sellador experimental a base de trióxido mineral / Citotoxicity of a mineral trioxide based experimental root canal sealer

El objetivo de este estudio fue determinar la citotoxicidad no específica de un sellador endodóntico experimental a base del polvo de ProRoot (MTA) mezclado con una resina polivinílica de base acuosa como vehículo en reemplazo del agua destilada, comparándolo con un material original, mediante la técnica de extendido en agar. Para el estudio se utilizaron 18 placas de Petri conteniendo las células L-929 en agar estéril, a las que se les adicionó solución de rojo neutro. Muestras preparadas de cemento Pro Root MTA y polvo de Pro Root MTA + resina polivinílica fueron colocadas en el interior de anillos circulares de silicona. Los controles positivos consistieron en los mismos anillos de silicona con hidróxido de Na al 10 por ciento y para los controles negativos se utilizaron los anillos vacíos. Todos los anillos fueron esterilizados con luz ultravioleta. Se colocaron 4 anillos por placa, conniendo los materiales a estudiar junto con los controles y se incubaron durante 24 hs en estufa gaseada a 37ºC en atmósfera de CO2, al 5 por ciento saturada de humedad. Las placas se examinaron utilizando un microscopio de óptica invertida con ocular micrométrico y se determinó el índice de decoloración y de lisis para cada especimen. Los resultados obtenidos indicaron que las muestras de Pro Root y polvo de Pro Root con una resina polivinílica presentaron el mismo nivel de citotoxicidad, ya que el área de decoloración y lisis se circunscribió a la superficie que se encontraba justo por debajo del material ensayado. En el caso del control positivo (hidróxido de sodio) el halo de decoloración y lisis superó los 6mm desde el material ensayado. El control negativo no presentó decoloración ni lisis, aún debajo de la superficie del mismo. A la luz de los resultados obtenidos con la metodología utilizada podemos concluir que el uso de una emulsión acuosa de alcoholes polivinílicos mezclado con polvo de Pro Root (MTA) no altera la citotoxicidad del material original.

Enucleated L929 mouse fibroblasts support invasion and multiplication of Shigella flexneri 5a

Invasive bacteria can induce their own uptake and specify their intracellular localization; hence it is commonly assumed that proximate modulation of host cell transcription is not required for infection. However, bacteria can also modulate, directly or indirectly, the transcription of many host cell genes, whose role in the infection may be difficult to determine by global gene expression. Is the host cell nucleus proximately required for intracellular infection and, if so, for which pathogens and at what stages of infection? Enucleated cells were previously infected with Toxoplasma gondii, Chlamydia psittaci, C. trachomatis, or Rickettsia prowazekii. We enucleated L929 mouse fibroblasts by centrifugation in the presence of cytochalasin B, and compared the infection with Shigella flexneri M90T 5a of nucleated and enucleated cells. Percent infection and bacterial loads were estimated with a gentamicin suppression assay in cultures fixed and stained at different times after infection. Enucleation reduced by about half the percent of infected cells, a finding that may reflect the reduced endocytic ability of L929 cytoplasts. However, average numbers of bacteria and frequency distributions of bacterial numbers per cell at different times were similar in enucleated and nucleated cells. Bacteria with actin-rich tails were detected in both cytoplasts and nucleated cells. Lastly, cytoplasts were similarly infected 2 and 24 h after enucleation, suggesting that short-lived mRNAs were not involved in the infection. Productive S. flexneri infection could thus take place in cells unable to modulate gene transcription, RNA processing, or nucleus-dependent signaling cascades.

Changes of tumor necrosis factor, surfactant protein A, and phospholipids in bronchoalveolar lavage fluid in the development and progression of coal workers' pneumoconiosis / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To evaluate the alterations of biomarkers in the development and progression of coal workers' pneumoconiosis (CWP).</p><p><b>METHODS</b>The type and number of cells, and the levels of tumor necrosis factor-alpha (TNF-alpha), pulmonary surfactant protein, phospholipids and fibronectin in bronchoalveolar lavage fluid were assayed in 14 health active coal miners, 21 coal miners without CWP and 13 miners with CWP of 0/1 to 1/1.</p><p><b>RESULTS</b>Compared to active coal miners without CWP (8.23 microg/mL), TNF-alpha concentration was gradually decreased when dust exposure was stopped (5.90 microg/mL). Elevated surfactant protein A (SP-A) level and phosphatidylglycerol (PG) to phosphatidylinositol (PI) ratio were found in miners actively exposed to coal dust (6528 ng/mL for SP-A and 10. for PG/PI), and both parameters decreased when CWP progressed from CWP (0/1) (3419 microg/mL for SP-A and 5.9 for PG/PI) to CWP (1/1) (1654 microg/mL for SP-A and 5.5 for PG/PI).</p><p><b>CONCLUSION</b>Biomarkers in bronchoalveolar lavage fluid can be used to screen coal miners at high risk of developing coal workers' pneumoconiosis.</p>

Citotoxidade de três cimentos obturadores do sistema de canais radiculares sobre cultura de células L929 / Citotoxicity of three filling cements of radicular canals system over L929 culture cells

O objetivo desse estudo in vitro foi avaliar a citotoxicidade dos cimentos Intrafill e Pulp Canal Sealer, ambos à base de óxido de zinco eugenol e um outro cimento, o Sealapex, à base de hidróxido de cálcio. Esse experimento foi realizado usando linhagem de células L 929 (de fibroblastos de camundongos). A citotoxicidade foi avaliada in vitro, usando-se o método de difusão em Agar, depois de 48 horas do endurecimento do cimento, o corante utilizado foi o vermelho neutro. Os resultados mostraram diferenças nas médias dos valores da viabilidade celular pelo teste ANOVA. Após o período determinado pela amostra, o Intrafill, e o Sealapex apresentaram alterações morfológicas celulares com maior citotoxicidade quando comparados ao Pulp Canal Sealer.

Cell death induced by hydroxyapatite on L929 fibroblast cells

Biomaterials intended for end-use application as bone-graft substitutes have to undergo safety evaluation. In this study, we investigated the in vitro cytotoxic effects especially to determine the mode of death of two hydroxyapatite compounds (HA2, HA3) which were synthesized locally. The methods used for cytotoxicity was the standard MTT assay whereas AO/PI staining was performed to determine the mode of cell death in HA treated L929 fibroblasts. Our results demonstrated that both HA2 and HA3 were not significantly cytotoxic as more than 75% cells after 72 hours treatment were viable. Furthermore, we found that the major mode of cell death in HA treated cells was apoptosis. In conclusion, our results demonstrated that these hydroxyapatite compounds are not cytotoxic where the mode of death was primarily via apoptosis.

DNA damage evaluation of hydroxyapatite on fibroblast cell L929 using the single cell gel electrophoresis assay

Hydroxyapatite is the main component of the bone which is a potential biomaterial substance that can be applied in orthopaedics. In this study, the biocompatibility of this biomaterial was assessed using an in vitro technique. The cytotoxicity and genotoxicity effect of HA2 and HA3 against L929 fibroblast cell was evaluated using the MTT Assay and Alkaline Comet Assay respectively. Both HA2 and HA3 compound showed low cytotoxicity effect as determined using MTT Assay. Cells viability following 72 hours incubation at maximum concentration of both HA2 and HA3 (200 mg/ml) were 75.3 +/- 8.8% and 86.7 +/- 13.1% respectively. However, the cytotoxicity effect of ZnSO4.7H2O as a positive control showed an IC50 values of 46 mg/ml (160 microM). On the other hand, both HA2 and HA3 compound showed a slight genotoxicity effect as determined using the Alkaline Comet Assay following incubation at the concentration 200 mg/ml for 72 hours. This assay has been widely used in genetic toxicology to detect DNA strand breaks and alkali-labile site. The percentage of the cells with DNA damage for both substance was 27.7 +/- 1.3% and 15.6 +/- 1.0% for HA2 and HA3 respectively. Incubation of the cells for 24 hours with 38 microg/ml (IC25) of positive control showed an increase in percentage of cells with DNA damage (67.5 +/- 0.7%). In conclusion, our study indicated that both hydroxyapatite compounds showed a good biocompatibility in fibroblast cells.

A study of oral epithelial cells cultured with L929 cells as seed cells in vitro / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To purpose of study aimed at investigating the technique of culturing oral epithelia in vitro and to set up an experimental model for further reconstructing oral mucosa in vitro.</p><p><b>METHODS</b>The oral mucosa was taken from young New Zealand rabbits, and the mucosa was digested with enzyme and suspended in liquid to form cellular suspension. Being seeded, the cells were cultured motionlessly. The medium was changed regularly and the cells were subcultured.</p><p><b>RESULTS</b>The cultured cells were all epithelial cells without fibroblasts, and they were proved to be diploid cells. The cells were subcultured in 1-13 generations which survived for 50-60 days.</p><p><b>CONCLUSION</b>The oral epithelium of young New Zealand rabbit can be cultured in vitro, maintaining the ability to proliferate in a certain period. It is a pilot study to reconstruct oral tissue in vitro.</p>

Seroprevalence of scrub typhus infection in patients with pyrexia at some malaria clinics in three western provinces of Thailand.

In Thailand, the epidemiological data on scrub typhus infection represents only "the tip of an iceberg" especially in malaria clinics where patients come to seek attention because of other febrile illnesses that may have initial clinical signs that are indistinguishable from malaria. The objectives of this study were to determine the prevalence of antibody titers to Orientia tsutsugamushi, and its various strains, among patients at some malaria clinics in three western provinces of Thailand. The sample was represented by 200 patients from 6 malaria clinics in Ratchaburi, Petchaburi and Kanchanaburi provinces between June and November, 1994. Blood specimens were collected with their consent. Immunofluorescent antibody assays (IFA) were used for measuring IgM and IgG antibody titers for scrub typhus infection. The results showed that the prevalence rate for scrub typhus infection (IgM and/or IgG titer > or = 50) was 59.50% (119 cases). The immunofluorescent antibody response to various strains of O. tsutsugamushi showed that co-infections with the Karp, the Gilliam and the Kato strains were the most common (found in 68.10% of cases). Geometric mean antibody titers (GMT) were highest for the Karp strain, followed by the Gilliam then Kato strains. In conclusion, this study indicates that the prevalence rate of scrub typhus is not rare in these areas.

Cell-mediated immunosuppression in mice by street rabies virus not restored by calcium ionophore or PMA.

It is known that rabies virus can suppress the host immune system. In this study we demonstrate a depression of cell-mediated immunity in mice, peripherally infected with Thai street rabies virus. The cell-mediated cytolysis of spleen cells from mice increased transiently on day 5 after infection and declined rapidly thereafter until death. The proliferation of spleen cells stimulated with a T-cell mitogen such as phytohemagglutinin or concanavalin A, was significantly suppressed during the course of infection. There was also a marked suppression of IL-2 secretion in parallel with a decrease of the T-cell proliferative response to mitogen. The suppression of T-cell proliferation was not restored by treatment with a calcium ionophore (A 23187) or phorbol 12-myristate-13 acetate (PMA).

Estudio sobre el factor de crecimiento epidérmico:III obtención de moléculas EGF equivalentes, a partir del medio condicionado de células L929 / Studies on the epidermal growth factor (EGF):III obtention of EGF-like molecules from L-929 cell culture conditioned medio

El Factor de Crecimiento Epidérmico ha sido recientemente purificado a partir de glándulas submaxilares de ratón y a partir de orina humana. Sin embargo, existen evidencias que indican que los factores de crecimiento liberados por células transformadas en cultivo, aunque reconocen el receptor del factor de crecimiento epidérmico, son moléculas diferentes. Por su capacidad de crecimiento in vitro con poco suplemento de suero, las células L929 son especialmente adecuadas para cultivos en masa. En este trabajo presentamos evidencias de que las células L929, mantenidas en medio sin suero, libran al espacio extracelular moléculas que reconocen el receptor del Factor de Crecimiento Epidérmico. Estas moléculas muestran un peso molecular aparente (en cromatografía de filtración en gel) cercano a 6 000; son estables en medio ácido a temperatura ambiente. Sin embargo, su comportamiento de adsorción en matrices de acrilamida es diferente al del EGF