Cytochemical localization of 5′-nucleotidase in the enteric ganglia and in smooth muscle cells of the guinea-pig

Brain Cell Biology - Cytochemical techniques were used to study the localization of 5′-nucleotidase in the enteric ganglia and in smooth muscle cells of the guinea-pig ileum, iris and vas...     

Compounds in urban air compete with 2,3,7,8-tetrachlorodibenzo-p-dioxin for binding to the receptor protein

Acetone extracts of filter-collected urban airborne particulate matter contain compounds which can competitively inhibit 2,3,7,8-[1,6-3H]tetrachlorodibenzo-p-dioxin (TCDD) binding to the rat liver TCDD-receptor protein. The concentration of conventional polycyclic aromatic hydrocarbons (PAHs) or chlorinated dioxins and dibenzofurans cannot account for more than 1-30% of the observed competition for [3H]TCDD binding to the receptor protein. The difference in potency between samples collected in urban areas during different periods of the year and a background sample is 25-400-fold. Collecting samples in the presence of increased concentrations of nitrogen dioxide, nitrous acid, nitric acid or ozone did not increase the amount of compounds with receptor affinity. However, with nitrogen dioxide and especially with nitric acid, a substantial increase of the mutagenic effects in the Ames Salmonella assay in the absence of mammalian activation as well as a degradation of several PAHs were noted. Affinity for the TCDD-receptor protein, mutagenicity in the absence of mammalian metabolic activation in the Ames Salmonella assay and PAH-content are characteristics of urban particulate matter showing the presence of compounds, that represent potential health risks. The compounds with affinity for the receptor may constitute a group of substances different from both conventional PAHs and direct-acting mutagens.     

Phytotron cultivation of early barley mutants

Conclusions The authors have tried to gather data which permit some information on the between and within locus reactions of induced early barley mutants to different photo- and thermoperiods. Eight mutant cases, showing rather drastic earliness in field cultivation and representing three different gene loci, were examined in phytotron experiments according to routine methods of cultivation. One of the mutants, mat-a ⁸, has been released as an original Swedish barley variety under the name of Svalöf's Mari. In a previous publication (Dormling et al., 1966) this mutant was compared to its parent variety, Svalöf's Bonus, under 30 different climatic conditions. In the present investigation three photoperiods (24, 16 and 8 hours of artificial light) were combined with three suitable thermoperiods (20-15°, 20-10° and 15-10°C).The results indicate that photoperiodic insensitivity, with regard to ear formation and heading capacity, as well as kernel production, is of rather frequent occurrence in connection with drastically early mutants in barley. Four out of eight induced mutants give a more or less pronounced insensitivity. Three of the four insensitive mutants represent locus a, one belongs to locus b. Of the two c-mutants none was insensitive; both were on the contrary pronounced long-day types.Photo- and thermoperiods interact in various ways. This is especially clear in the c-mutants just mentioned, which have a high generative productivity and efficiency at continuous light and high thermoperiods. They produce no grain but considerable vegetative matter at 8 hours of light, independently of thermoperiod, as well as at 16 hours of light with high temperatures. In fact, mutants of loci a and c differ strikingly with regard to their relations to the climatic conditions applied. The insensitive mutant b ¹³ is remarkably similar to the mutant a ¹², but its resemblance to the sensitive mutants b ⁷ and b ¹⁰ of the same locus is evidenced by its high average internode number.It ought to be pointed out here that the mutants of the three gene loci analysed in this study can be distinguished phenotypically with regard to morphological as well as physiological properties, in the field as well as in phytotron cultivation. The c-mutants are especially characteristic. However, there also seem to be clear differences in reaction between the allelic mutants of a locus. In fact, all eight mutants studied seem to react more or less differently.The insensitive mutant a ⁸, which has been released into practice, is also widely used in recombination work, and successful segregates have been isolated. The characteristics of a ⁸, which make the mutant valuable in practice, are also found in phytotron experimentation, specially with regard to earliness, generative efficiency and yield. Also the semidwarf habit and the insensitivity to changes in photo- and thermoperiods readily show up.This investigation has been generously supported by the Swedish Research Council of Forestry and Agriculture.     

Studies on the metabolism of steroids in the foetus. Biosynthesis of 6α-hydroxytestosterone in the human foetal liver

After incubation of testosterone with 105000g microsomes of human foetal liver, 6alpha-hydroxytestosterone was isolated and identified by t.l.c. and g.l.c.-mass spectrometry. This is the first example of 6alpha-hydroxylation of C(19) steroids in the human liver, and the finding is discussed in relation to earlier reports of 6-oxygenated C(19) and C(18) steroids in pregnant women.     

Hormonal regulation of estrogen receptor messenger ribonucleic acid in T47Dco and MCF-7 breast cancer cells

Using a combination of hormone-binding assays, immunologic techniques, and mRNA hybridizations we have measured the estrogen receptor (ER) content and studied the hormonal regulation of ER mRNA in one estrogen responsive and one estrogen unresponsive breast cancer cell line, MCF-7 and T47Dco, respectively. Estradiol binding could be detected in cytosol from MCF-7 cells but not in T47Dco cells. However, when measured by an enzyme-linked immunosorbent assay, T47Dco cells were found to contain approximately 15 fmol ER/mg cytosolic protein or 10% of the ER content in MCF-7 cells. Immunologically reactive ER in T47Dco cells was indistinguishable in size (approximately equal to 68 KD) from the ER in MCF-7 cells, as shown by Western blotting using a monoclonal antihuman ER antibody. Quantification of ER mRNA in MCF-7 and T47Dco cells indicated that T47Dco cells contained approximately 50% of the ER mRNA levels found in MCF-7 cells. This basal level of ER mRNA in T47Dco cells was not decreased by estradiol treatment, as opposed to in MCF-7 cells where estradiol caused 40-60% decrease in the ER mRNA expression. Also, estradiol did not increase the progesterone receptor (PR) mRNA levels in T47Dco cells whereas in MCF-7 cells an approximately 5-fold increase of the PR mRNA levels occurred after estradiol treatment. However, incubation of the cells with the synthetic progestin R5020 decreased the ER mRNA levels to approximately the same degree in both cell lines. In conclusion, we have shown that estrogen down-regulates ER mRNA and up-regulates PR mRNA in MCF-7 cells. Neither of these estrogenic effects were seen in T47Dco cells. It appears that the steroid-resistance in T47Dco cells does not occur as a consequence of a complete absence of ER mRNA or protein.(ABSTRACT TRUNCATED AT 250 WORDS)     

Glial fibrillary acidic protein and desmin in salivary neoplasms. Expression of four different types of intermediate filament proteins within the same cell type

The presence of intermediate filament proteins (IFP) in normal salivary gland tissue and investigated by immunohistochemical techniques on frozen sections. Cytokeratins (CKs) were seen in almost all normal epithelial cells. In the parotid gland and in palatal gland tissue, a co-expression of cytokeratin and glial fibrillary acidic protein (GFAP) was seen in some myoepithelial cells, but this was not apparent in the submandibular gland. In some pleomorphic adenomas, carcinomas in pleomorphic adenomas, one mucoepidermoid carcinoma, one mucus-producing adenopapillary carcinoma and one adenoid cystic carcinoma, cells expressing three different IFP classes were found (CKs, vimentin, GFAP). These cells were most often situated peripherally in the tumour cords or ducts. The cytokeratin pattern in these cells, as revealed by mAbs PKK1-3, was similar to that in normal myoepithelial cells. Furthermore, reactivity for a fourth class of IFP, desmin, could be seen in this cell type in two carcinomas in pleomorphic adenomas, and also in a few cells in a pleomorphic adenoma and an adenoid cystic carcinoma. Thus the pattern of IFP expression in salivary gland neoplasms, is very complex, and cannot always be related to the normal tissue.