Binding of flunitrazepam to differentiating neurons cultured in a chemically defined,hormone-supplemented medium

[³H]Flunitrazepam (FNZ) binding to cortical neurons from fetal rat brain was investigated in vitro. The use of a synthetic medium specific for neurons made it possible to plot a developmental curve of³H-FNZ binding in an almost pure neuronal culture. Detectable specific binding was present in vitro at time 0 (that is, the 16th gestational day). A progressive increase of binding, due to an increment in the number of recognition sites, was observed on the subsequent days. The affinity of the specific binding sites to³H-FNZ was enhanced by the addition of exogenous GABA, whereas the density was not affected.     

Suramin, a novel antitumor compound

Suramin, a polyanionic compound originally synthesized for use as an antiparasitic agent, has recently entered clinical trials for the treatment of a variety of human cancers refractory to conventional modalities of therapy. This is based on suramin's ability to bind and to inactivate growth factor and enzyme systems critical to cellular homeostasis and proliferation. In addition, this compound possesses adrenocorticolytic properties in vivo and exerts significant cytostatic and cytocidal effects against a variety of human tumor cell lines in vitro. Pilot studies using suramin have thus far been conducted in adrenocortical carcinoma, prostate cancer refractory to conventional hormonal manipulation and nodular lymphomas.     

黔桂边境六县植物区系组成及其特点

黔桂边境六县植物区系有维管束植物203科921属2255种(变种)。其中种子植物含25种以上的有22科,代表成分有樟科、山茶科、壳斗科、五加科、桑科和椴树科。区系的特点是:地理成分复杂、分布交错;热带、亚热带性质明显;区系起源古老;特有珍稀种类多;喜酸成分较喜钙成分占优势;草本与木本种类近等。此外,对本区系自然条件及植物资源利用也作了简述。     

Short term increase in risk of breast cancer after full term pregnancy.

To determine whether there is a short term increase in the risk of breast cancer after a full term birth data from two hospital based, case-control studies in Italy were pooled. Analysis was restricted to women aged under 50 with two or more children (573 women with cancer and 570 controls). A relative risk for breast cancer of 2.66 was seen in women who had given birth during the three years preceding the interview compared with women whose last birth had occurred 10 or more years before, after adjustment for age, age at first birth, and parity. The relative risk slowly decreased for women who had last given birth three to 10 years before. Multivariate analyses confirmed the protective effect of an early age at first birth and the age dependent effect of parity on the risk of breast cancer--that is, a direct relation below age 40 and an inverse one in older women. These data provide epidemiological evidence that a full term birth is followed by a transient increase in the risk of breast cancer, which for some time contrasts with and overcomes the long term protection of pregnancy at an early age. They therefore confirm predictions from animal studies and theoretical models that pregnancy prevents the early stages of breast carcinogenesis but promotes the late stages of the process.     

Effect of TSH in human thyroid cells: evidence for both mitogenic and antimitogenic effects.

The well-known mitogenic effects of TSH observed in vivo on the thyroid are not always reproducible of human thyroid cells in vitro where conflicting results have been obtained. In order to clarify this issue, we have used primary cultures of human thyroid cells obtained from normal tissue and maintained in serum-free medium for several days. In this in vitro model we have studied the effect of TSH on growth by measuring three different parameters: [3H]-thymidine incorporation, cell counts, and DNA measurement. Monolayer cultures were plated at both low and high cell density (2 x 10(4) and 8 x 10(4) cells/25 mm well, respectively). Although at either cell density cultures were equally able to functionally respond to TSH in terms of cAMP accumulation a significant growth response to TSH was observed only in low density cultures. In high density cultures TSH had an antimitogenic effect. Moreover, TSH potentiated the mitogenic effect of insulin only in low density cultures. In contrast to TSH, FCS induced a similar proliferative response at both high and low cell density. Following TSH stimulation, cAMP content was always increased, paralleling the effect of growth in low density but not in high density cultures. The cAMP analogues dibutyryl-cAMP and 8-bromo-cAMP, as well as cholera toxin and forskolin, did not mimic the mitogenic effect of TSH but had an antiproliferative effect. In addition, these agents blunted the proliferative effect of insulin. These data suggest that in thyroid cells TSH is able to elicit both a mitogenic and an antimitogenic effect depending on the environmental conditions such as cell density.(ABSTRACT TRUNCATED AT 250 WORDS)     

Control of early seedling growth in varietal lines of hexaploid wheat (Triticum aestivum), durum wheat (Triticum durum), and barley (Hordeum vulgare) in response to the phthalimide growth regulant,AC 94,377

AC 94,377 caused elongation of seedlings of Triticum aestivum, Triticum durum, and Hordeum vulgare when applied to the soil, or the soil plus seed at planting. Affected were the leaf sheathes and the coleoptiles, and at high compound rates there was premature elongation of the stem internodes. As exemplified by the response of T. aestivum var. Fidel, the influence on coleoptile elongation was greatest under conditions whereby the coleoptile was naturally stimulated to elongate, i.e., when growth was in the dark and temperatures were cool (15°C). All of the stem internodes were capable of elongation except the one below the coleoptile node. The effect on leaf sheath elongation was prolonged when compared to activity of gibberellic acid.Several varieties of the three cereal species were examined in the greenhouse for sensitivity to AC 94,377 in order to evaluate the extent of the response. All of the barley varieties examined were sensitive to AC 94,377, elongating regardless of the planting conditions. Two such conditions were established, including incubation under warm (28/20°C) conditions following planting the grains 1 cm deep, and incubation under cool (22/16°C) conditions following planting the grains 6 cm deep. Wheat varieties distributed into two general categories, those which were sensitive and those which were not. The insensitivity correlated well to the presence of the reduced height (Rht) and GA-insensitive (Gai) genes in Triticum aestivum and Triticum durum, respectively. Thus, AC 94,377 can be used conveniently to evaluate varietal lines for the presence of this phenotype. This correlation also lends support to the notion that the Rht/Gai mutations in wheat are either at the level of a gibberellin receptor or at a step in the signal transduction pathway.     

Use of ars18 based vectors to increase protein production in Yarrowia lipolytica.

The isolation of ars sequence from the yeast Yarrowia lipolytica has recently been reported (Fournier et al., 1991). Vectors containing ars18 have been used to increase homologous and heterologous protein production. Examples presented are the Yarrowia lipolytica alkaline extracellular protease (AEP), the porcine alpha 1-interferon and the bovine prochymosin. A 2- to 6-fold increase in the corresponding protein production was observed and in several cases it was established that it corresponded to the copy number of plasmid in the cell.