Loci for human U1 RNA: structural and evolutionary implications

Three clones U1-1, U1-6, and U1-8 containing sequences related to human U1 RNA have been studied by sequence analysis. The results show that each of the three clones represents a distinct locus. The U1-6 locus is closely related to the HU1-1 locus, which is believed to represent a functional U1 gene. The U1-1 and U1-8 loci are pseudogenes by definition, since they contain sequences that are closely related to but not identical with the human U1 RNA sequence. The U1-6 locus contains the sequence T-A-T-A-T close to the 5'-end of the U1 sequence but it is unclear if this represents the promoter. When the U1-8 locus was compared to the U1-6 locus, it was observed that the 5'-flanking sequences, except in the immediate vicinity of the pseudogene, are as well-conserved as the U1-related sequence itself, at least up to position -220. The high degree of homology in the 5'-flanking region suggests that U1 genes have a much more strict sequence requirement with regard to 5'-flanking sequences than most other eukaryotic genes. The U1-6 and U1-8 loci contain the sequence T-A-T-G-T-A-G-A-T-G-A between positions -211 and -221. An identical sequence is present in the equivalent position in the HU1-1 locus, and may represent the promoter. The high degree of conservation in the postulated promoter region indicates that pseudogenes like U1-8 possibly could be expressed. A truncated U1-related sequence is present between 106 to 150 nucleotides upstream from the U1 gene/pseudogene in the U1-6, the U1-8 and the HU1-1 loci, suggesting that the U1 genes may have been clustered early in evolution. The U1-1 locus has a strikingly different structure from the U1-8 locus; the pseudogene itself is as closely related to the U1 RNA sequence as is the U1-8 pseudogene but the flanking sequences, both on the 5' and the 3' side, share no detectable homology with the corresponding regions in the U1-6 or U1-8 loci. It may therefore be postulated that small nuclear RNA pseudogenes are created by several different mechanisms.     

Antigens of Ambrosia elatior (short ragweed) pollen. III. Crossed radioimmunoelectrophoresis of ragweed-allergic patients' sera with special attention to quantification of IgE responses

Short ragweed allergenic extract has been studied by means of crossed radioimmunoelectrophoresis (CRIE) with the use of sera from 37 allergic patients and the relevant control sera. In this study 22 of 52 antigens, detectable in crossed immunoelectrophoresis (CIE) against polyspecific rabbit anti-ragweed IgG, were able to bind specific human IgE to their corresponding immunoprecipitates. This binding was semiquantified by comparison with the binding of a standard serum pool. Nine antigens were identified as important allergens, including the previously isolated components, AgE, AgK, and Ra6. Certain allergens (e.g., AgE, AgK, and Ag 31) bound IgE in almost all patients' sera, whereas others showed a bimodal distribution for sera of responder and nonresponder patients. The total CRIE score was found to correlate significantly both with ragweed-specific serum IgE antibody determined by RAST (rs = 0.88; p less than 0.001) and with total IgE level (rs = 0.55; p less than 0.01). Patient's CRIE scores to AgE also correlated significantly with their specific IgE antibody to AgE measured by RIA (r = 0.47; p less than 0.01) and with skin-test sensitivity to AgE (r = 0.44; p less than 0.05). It was concluded that CRIE is well suited for identification of important ragweed allergens without the previous need for laborious isolation procedures.     

Antigenic relationships between human and cobra complement factors C3 and cobra venom factor (CVF) from the Indian cobra (Naja naja)

The presence of a factor immunologically related to cobra venom factor (CVF) was demonstrated in serum and plasma from the Indian cobra (Naja naja kaoutia). The factor was purified from cobra plasma by affinity chromatography on an anti-CVF gel and was found to consist of a protein composed of two polypeptide chains similar in size to those of human C3. With use of immunoblotting technique, common antigenic determinants were found in the smaller chain of the prepared material and the beta-chain of human C3; the larger chain may display antigenic determinants present in the alpha-chain of human C3. These findings suggest that this molecule represents the C3 of the cobra complement system. Common antigenic determinants were also demonstrated in the alpha-chain of CVF and the beta-chains of human and cobra C3. No reactions were observed between the beta- and gamma-chains of CVF and any antiserum against human C3 or its subunits. Upon immunodiffusion analysis, cobra serum was found to contain a factor besides C3 sharing antigens specific for CVF, while cobra C3 was antigenically deficient compared to CVF. This suggests that cobra C3 physiologically is degraded to a molecule very similar to or identical with CVF.     

Blood osmolality in vitro: dependence on PCO2, lactic acid concentration, and O2 saturation

Changes of osmolality (Osm) were measured by freezing-point determination in true plasma of 10 healthy subjects. This was done after equilibration with CO2 (0.5-10.0%), after the addition of lactic acid (10 and 20 mmol/l), and after deoxygenation. The graph for the dependence of Osm on CO2 partial pressure (PCO2) in oxygenated blood resembles the classical CO2 absorption curve. The increase of Osm with PCO2 (approximately 0.2 mosmol . kg H2O-1 . Torr-1) is almost as great as the increase in dissolved CO2 plus bicarbonate (HCO-3). Addition of lactic acid shifts the curve upward by only 0.6 mosmol/mmol because of displacement of HCO-3. Deoxygenation has no significant effect at constant PCO2 despite an increase in [HCO-3]. This is probably due to the binding of 2,3-diphosphoglycerate to hemoglobin. It can be seen in the Osm-pH diagram that differences between CO2 and lactic acid titration largely disappear. For each lactic acid concentration there is a linear dependence corresponding to the linear [HCO-3]-pH relation in plasma. At constant pH, Osm increases after deoxygenation. The observed in vitro relation might explain part of the osmolality increase during physical exercise.     

A Hungarian twin study on hand clasping, arm folding and tongue curling

A twin study was performed in adult Hungarian monozygotic and dizygotic pairs for hand clasping, arm folding and tongue curling. Genetic background of these traits could not be confirmed, although there appears to be a positive correlation between hand clasping type and handedness.     

Cyclic nucleotides modulate the release of [3H] adenosine cyclic 3',5'-phosphate bound to the regulatory moiety of protein kinase I by the catalytic subunit of the kinase

The rate of release of bound c[3H]AMP from the two types (A and B) of cAMP binding sites on the regulatory subunit dimer (R2I) of rabbit muscle protein kinase I was studied in the presence of the catalytic (C) subunit of protein kinase. Rebinding of released c[3H]AMP was avoided by using highly diluted reactants or adding unlabeled cAMP or its analogues. No significant C-induced dissociation of R2I-(c[3H]AMP)4 occurred in the absence of Mg2+-ATP. Of the two options that one or two molecules of C are required to induce the release of c[3H]AMP bound to R2I, only the first one was compatible with the first-order dependence on [C] of the rate of release of c[3H]AMP observed over a wide range of C concentrations. In the absence of added unlabeled cyclic nucleotide, the rate of the C-induced release of c[3H]AMP was the same from site A and site B. The apparent second-order rate constant for the association of C to R2I(c[3H]AMP)4 was 6 X 10(6) M-1 s-1 (37 degrees C, 0.15 M KCl). Raising the concentration of unlabeled cAMP in the medium up to 1 microM decreased by up to 50% the rate of the C-induced release of bound c[3H]AMP from both sites. This is explained by assuming that the association of one molecule of C to R2I(c-[3H]AMP)4 leads to the release of c[3H]AMP first from one R subunit and subsequently, by a process that can be blocked by about 1 microM cAMP, from the other R subunit. A further rise of the cAMP concentration decreased the rate of release from site B only, so that the C-induced release of c[3H]AMP occurred almost exclusively from site A at very high concentrations of cAMP. This suggests that c[3H]AMP is released first from site A and that this vacant site by interacting with cAMP inhibits the release of c[3H]AMP from site B of the same R subunit. The role of site A in controlling the C-induced release was further supported by the finding that several cAMP analogues inhibited the release with potencies correlating with their affinities for site A. The C-induced release of c[3H]AMP from aged R2I was about 10 times slower than that from fresh R2I. No significant C-induced release of c[3H]AMP was observed from the monomeric fragment obtained by limited trypsin treatment of R2(1).     

User requirements on CT-based computed dose planning systems in radiation therapy. Presentation of 'check lists'

The expanding use of computers in radiation therapy procedures, especially the rapidly increasing use of digital CT-information, necessitates the coordination of the different systems in order to facilitate their developments. In order to define necessary demands for tomorrow a Nordic cooperation was initiated 1981 by NORDFORSK (Nordic co-operative organization for applied research), and a group of physicians and physicists having their daily work in this field of medicine and physics was invited to produce a report on 'User requirements on CT-based computed dose planning systems on radiation therapy'. The work has been done within the frame of NORDFORSK's activities and has been independent of the existing commissions and associations in the radiology field, but it has taken into consideration recommendations that have been given by or are being produced by other organizations. This report is a short summary of the complete paper which will be published in Acta Radiologica. The aim of this short version is to get an early presentation of the 'requirement lists' (see Appendix) which we think are of immediate importance.     

A paired-tracer dilution method for characterizing membrane transport in the perfused rat hindlimb. Effects of insulin, feeding and fasting on the kinetics of sugar transport.

We have applied the paired-tracer dilution method to the study of transport processes in a mixed mammalian muscle preparation, the perfused rat hindlimb. The method is suitable for the characterization of the kinetic parameters of sugar and amino acid transport and its regulation by hormones, contractile activity, hypoxia, etc. Insulin stimulates sugar transport by increasing the Vmax. of the process 2-3 fold, but its affinity is unchanged. Starvation increases the affinity of sugar transport in perfused skeletal muscle.     

The effects of 24R,25-dihydroxycholecalciferol and of 1 alpha,25-dihydroxycholecalciferol on ornithine decarboxylase activity and on DNA synthesis in the epiphysis and diaphysis of rat bone and in the duodenum.

The effect of cholecalciferol metabolites on ornithine decarboxylase activity and on DNA synthesis in developing long bones was investigated in vitamin D-depleted rats. In the epiphysis there was a 6.4-fold increase in ornithine decarboxylase activity 5 h after a single injection of 24R,25-dihydroxycholecalciferol but not of 24S,25-dihydroxycholecalciferol or other vitamin D metabolites. In comparison, in the diaphysis and duodenum, 1 alpha,25-dihydroxycholecalciferol, but not other vitamin D metabolites, caused a 3-3.5-fold increase in the enzyme activity. The enzyme activity in the tissues examined attained a maximal value at 5 h after the injection of the metabolites. The activity of ornithine decarboxylase in the epiphysial region increased dose-dependently as the result of a single injection of 24R,25-dihydroxycholecalciferol and attained a maximal value at a dose between 30 and 3000 ng. In addition, administration of 24R,25-dihydroxycholecalciferol, but not 24S,25-dihydroxycholecalciferol or other metabolites, caused within 24 h a 1.7-2.0-fold increase in [3H]thymidine incorporation into DNA of the epiphyses of tibial bones. In comparison, 1 alpha,25-dihydroxycholecalciferol caused a 1.5-fold increase in [3H]thymidine incorporation into DNA of the diaphyses and of the duodenum. The present data indicate that 24R,25-dihydroxycholecalciferol is involved in the regulation of epiphyseal growth, whereas 1 alpha,25,dihydroxycholecalciferol stimulates the proliferation of cells in the diaphysis of long bones and in the intestinal mucosa.