Mesenchymal-epithelial conversions induced by 5-Azacytidine: Appearance of cytokeratin Endo-A messenger RNA

When mouse-teratocarcinoma-derived fibroblasts (1246 cell line) are subjected to treatment with the inhibitor of DNA methylation, 5-Azacytidine (5 AzaC), they transiently express at 55-kilodalton intermediate-filament protein recognized by the epithelial-specific monoclonal antibody, TROMA-1, although they retain a fibroblastic morphology. However, rare clones (e.g., the 1339 cell line) that permanently express the antigen recognized by TROMA-1 can be derived from the 5 AzaC-treated 1246 population, and these clones have an epithelial phenotype. In the present study, we used cloned DNA probes to demonstrate that, in 1246 fibroblasts, 5 AzaC induces the appearance of Endo-A mRNA. High levels of Endo-A mRNA were also detected in the epithelial derivative, cell line 1339. In both cases, the capping site of the Endo-A mRNA was found to be the same as that in epithelial cells which normally express this RNA.     

Age-Related Changes in Aldehyde Dehydrogenase Activity of Rat Brain, Liver, and Heart

Abstract: Aldehyde dehydrogenase (ALDH) activity was measured in brains, livers, and hearts of 23–26-month-old and 3-month-old rats. A significant increase of ALDH activity was found in whole brain of old rats with both acetaldehyde (39%) and propionylaldehyde (15%) used as substrates. In different brain areas of old rats, with acetaldehyde used as substrate, a significant increase of ALDH activity was found in striatum (30–50%) and cerebral cortex (37%). However, no significant difference in ALDH activity was found in livers and hearts of young and old rats. Preliminary experiments showed a significant increase of aldehyde reductase activity (52%) with p -nitrobenzaldehyde used as substrate in whole brain of old rats compared with young rats. The present work indicates that an increase of ALDH activity in brain of old rats may be an adaptive phenomenon.     

Ontogeny of vasoactive intestinal peptide in the human fetal digestive tract

Immunocytochemistry and radioimmunoassay were used to assess the appearance time and tissue distribution of vasoactive intestinal peptide (VIP) in the digestive tract of the human fetus. By radioimmunoassay, VIP was measurable from 10 weeks of gestation. The peptide was abundantly distributed in the jejuno-ileum and colon, where the tissue peptide concentration rose from 9-14 weeks of gestation (18.4 +/- 4.4 and 22.0 +/- 5.0 pmol/g wet weight, respectively) to 15-21 weeks (83.0 +/- 21.1 and 98.6 +/- 36.4 pmol/g, respectively). Lower concentrations were recorded in pancreas from 9-14 weeks of gestation (4.3 +/- 0.8 pmol/g) to 15-21 weeks (13.9 +/- 3.7 pmol/g). The peptide concentration was 15.6 +/- 1.9 pmol/g in fundus and 25.5 +/- 3.2 pmol/g in antrum from 15 to 21 weeks of gestation. The highest concentration was recorded in duodenum from 15 to 21 weeks of gestation (118.4 +/- 40.8 pmol/g wet weight). Tissue VIP concentration and age were positively correlated in the jejuno-ileum. By immunofluorescence, immunoreactive VIP was localized in nervous fibers in the muscularis externa, in the submucosa and in the lamina propria. Scarce cell bodies were also found in the myenteric plexus. No immunofluorescent endocrine cells were observed. These results suggest: (1) the early appearance of immunoreactive VIP in gut, as early as 10 weeks of gestation; (2) the peptide, localized in nervous structures only, follows the same distribution pattern as that in adults; (3) the development of VIPergic structures is a continuous process, initiated during the 3rd month of pregnancy.     

An immunological study of the uncoupling protein of brown adipose tissue mitochondria

1. Ewes were injected with purified 32,000-Mr uncoupling protein from mitochondria of brown adipose tissue of cold-adapted rats in order to raise antibodies. 2. The existence of antibodies in the plasma of ewes and the cross-reactivity of plasmas were demonstrated and studied by 125I-labelled antigen-antibody reaction, double immunodiffusion, the inhibition of GDP binding to the 32,000 Mr protein and by immunohistochemistry. 3. The antibodies raised against the homogeneous protein yielded a single immunoprecipitation band with detergent-solubilized mitochondrial membranes of brown adipose tissue from rat, hamster, guinea-pig, rabbit and with the purified uncoupling protein of these animals. No immunoprecipitation was obtained with the protein purified from brown adipose tissue of term lamb foetus. 4. The GDP-binding activity of the uncoupling protein (isolated or in solubilized membranes) was largely inhibited by the antiserum. 5. The anti-(rat uncoupling protein) could not cross-react with solubilized membranes from liver or muscle, nor with the purified beef heart or rat liver ADP/ATP translocator.     

Experience using two CT-guided stereotactic biopsy methods

15 patients had intracranial CT-guided stereotactic biopsies. Biopsies were performed either with a Riechert-Mundinger stereotactic frame modified for use in the CT or by using the CT scan to establish the relationship of the intracranial lesion to identifiable bony landmarks, and subsequently performing the biopsy in a standard stereotactic frame. Both systems provided safe and accurate methods for obtaining intracranial tissue.     

Ultrastructural identification of corticotropes of the fetal rat

Corticotropes of rat fetuses aged 16, 18 and 21 days were localized by the indirect antibody-enzyme method on semithin sections of the pituitary. The development of the ultrastructure of these cells was observed on consecutive ultrathin sections. In comparison with previous data our present results show that identification of a fetal cell type cannot be based entirely on morphological criteria. The structural peculiarities of corticotropes obtained from studies in vivo are compared with those observed in cells maintained in vitro.     

A cDNA clone containing the entire coding sequence of a mouse H-2Kd histocompatibility antigen

We have isolated a cDNA clone carrying a 1560 bp long insert which contains the entire coding and 3' untranslated regions of an H-2K(d) mouse histocompatibility antigen. Its sequence and overal features are described. They point to the existence of unique properties of DNA sequences associated with the H-2K(d) antigen.