Immobilisation of monocytes to a solid support: a model for the study of ligand-binding interactions and plasminogen activation at the cell surface

The functional and immunological identification of receptors expressed by cells of the monocyte/macrophage lineage may be facilitated with the use of immobilised cells. A procedure is described here for attaching human blood monocytes, alveolar macrophages, and THP-1 cells to a solid support activated with polymerised glutaraldehyde. Homogeneous monolayers visualised by optical microscopy were obtained at predefined input cell densities and were quantitatively characterised with the use of ¹²⁵I-plasminogen (35000±2772 cells/well at 76000 cells/50 μL) and ¹²⁵I-pro-urokinase (39000±3839 cells/well at 86000 cells/50 μL). The cells remained stably attached during washing and incubation procedures in ligand-binding studies. The functionality of membrane receptors and acceptors of the immobilised cells for a number of ligands was verified. Parameters of the interaction of plasminogen, urokinase, and human immunoglobulin G with their corresponding receptors were similar to those previously reported using cells in suspension. The functionality of bound ligands, such as urokinase and plasminogen, was verified by measuring their ability to generate plasmin. We conclude that immobilised monocytes/macrophages are a useful tool for studying ligand interactions with membrane proteins and for the realisation of plasminogen activation studies at the surface of the cell membrane.     

Effect of ACTH on PTH-stimulated bone resorption in vitro

In vitro demonstration of PTH effects requires hormone concentrations greater than the "physiological" concentrations reported by radioimmunoassay or cytochemical assays. This discrepancy could be the result of binding or destruction of PTH at nonbiologically active sites. In the present study, ACTH was found to have no effect by itself on bone resorption, but addiction of ACTH to bone cultures together with low concentrations of PTH resulted in a specific enhancement of PTH-stimulated bone resorption. This effect was not observed when bone resorption was stimulated by PGE2 and 1,25(OH)2D3, and it was blocked by human serum. The effect of ACTH is similar to the enhancement in PTH-stimulated bone resorption by poly-l-lysine [7]. We suggest that the amplification of PTH stimulation was the result of displacement of PTH from nonbiologically active sites, making more PTH available for binding to its biologically active receptor. An alternative explanation for our results was that ACTH prevented degradation of PTH by bone-derived proteolytic enzymes. Thus the sensitivity of bioassays for PTH could be improved by adding ACTH.     

Bioavailability study of furosemide prodrugs in rats.

According to the hydrolysis performance "in vitro" and lipophylicity, two Furosemide (F) prodrugs were chosen from a series of acyloxymethylesters of F synthesized previously: P1 (acetyloxymethyl-4-chloro-N-furfuryl-5-sulfamoylanthranilate ) and P4 (pivaloyloxymethyl-4-chloro-N-furfuryl-5-sulfamoylanthranilate+ ++). The bioavailability studies were assayed over two groups of eight male Wistar rats as a randomized two-way crossover and balanced design: group 1) a solution of P1 in propylenglycol/ethyl acetate vs an aqueous solution of F, and group 2) P1 vs. P4 solutions in oleic acid (P1#, P4#). These assays showed a better absorption performance of P1 and P4 than F, while the two prodrugs showed a similar bioavailability. The oleic acid seems to be responsible for the delay in the recovery of 50% of the total amount of F excreted in urine (T50%). When the monitoring is done in plasma after the administration of P1#, P1 was not detected as circulating prodrug. The analytical determinations of F in urine and plasma were done by high performance liquid chromatography (HPLC). From the urinary excretion data, a slope that indicates a slow elimination was found with a half-life of 12 hours approximately.     

Treatment of small cell lung cancer with a combination of VP16-213 and cyclophosphamide with cisplatin or radiotherapy

Summary Fifty five patients with small cell lung cancer were treated with a VP16-213 combination chemotherapy regimen in two consectutive series. The first series included 24 patients; 10 with limited and 14 with extensive disease were treated with VP16-213, 120 mg/m² p.o. daily for 5 consecutive days, Cyclophosphamide 600 mg/m² i.v. and Cisplatin 80 mg/m² i.v. with hydratation and manitol induced diuresis. The cycle was repeated every 3 weeks. The second series included 31 similar patients, 16 limited, and 15 extensive disease, treated with VP16-213 at the same dose and Cyclophosphamide at 1,200 mg/m² i.v. also repeated every 3 weeks; after three cycles the patients were treated with radiotherapy to the primary tumor and regional lymph nodes with 4,000 rads in a split course of three weeks interval, followed by the same combination chemotherapy. Response rate was 75% for the first series with 6 of 24 (25%) of complete responses in four limited and two extensive disease and a median survival time of 24 weeks. In the second series of patients there were 26 of 31 (83.8%) responses with 10 of 31 (32%) complete responses in nine limited and one extensive disease and a median survival time of 33 weeks for responders. Duration of response for complete responders was 36.8 weeks for the first series and 51 weeks for the second. Toxicity was mild and includes nausea and vomiting, myelosupression, alopecia in both series, with one toxic death in the second series.Both regimens are active with a low complete response rate, which was increased in the second series by the addition of radiotherapy, which did not increase overall survival. Send offprint requests to H. Cortés Funes, Section Oncologia Medica, Servicio de Radioterapia y Oncologia     

Patterns of sediment dispersion coastwise the State of Bahia - Brazil

Using the average directions of the main wave-fronts which approach the coast of Bahia State - coinciding with that of the main wind occurring in the area - and of their periods, we define a wave climate model based on the construction of refraction diagrams. The resulting model of sediment transport was able to reproduce, in a general way, the sediment dispersion patterns furnished by geomorphic indicators of the littoral drift. These dispersion patterns control the generation of different types of sediment accumulations and of coastal stretches under erosion. We demonstrate that the presence of the Abrolhos and Corumbaú Point coral reefs is an important factor controlling the sediment dispersion patterns, since them act as a large protection against the waves action.     

Tackling stigma associated with intellectual disability among the general public: A study of two indirect contact interventions

Although evidence abounds that people with intellectual disabilities are exposed to stigma and discrimination, few interventions have attempted to tackle stigma among the general public. This study set out to assess the impact of two brief indirect contact interventions on lay people's inclusion attitudes, social distance and positive behavioral intentions, and to explore emotional reactions towards the two interventions. 925 participants completed the first online survey. Participants were randomized to watch either a 10 min film based on intergroup contact theory, or a film based on a protest message. In total, 403 participants completed the follow-up survey at one month. Both interventions were effective at changing inclusion attitudes and social distance in the short term and these effects were partially maintained at one month. The protest based intervention had a greater effect compared to the contact one on aspects of inclusion attitudes and evoked stronger emotional reactions. Despite small effect sizes, brief indirect contact interventions may have a potential role in tackling public stigma associated with intellectual disability but their effects on behavioral intentions are questionable.