Biomedical subjects
Publications and source records attributed to E Ulmer.
Previous studies demonstrated decreases in serum 25-hydroxyvitamin D in obese subjects. Studies were carried out to determine whiter serum vitamin D is low in obesity. The results indicate that serum vitamin D is significantly lower in obese than in nonobese individuals and may contribute to lower serum 25-hydroxyvitamin D in obesity.
The bacteriophage omega 18A, specific for Escherichia coli O18ac strains, was isolated from sewage. The results of host range and conjugation experiments showed that the sensitivity of bacteria to the phage is associated with the presence of O18ac antigens. With some of the O18 strains the phage omega 18A produces clear lysis on bacterial lawns only when applied at a high multiplicity and moreover the phage does not multiply. With the help of the phage omega 18A, E. coli O18ac strains could be divided into two serologically distinct subgroups called O18A and O18A1. E. coli strains belonging to the subgroup O18A are sensitive to phage omega 18A whereas bacteria of subgroup A1 are resistant.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The delay between the stimulus and the voluntary eye saccade is the only parameter of the saccadic system which can be measured by using standard apparatus. Taking manually the measurements made on records obtained by using minicomputer; the authors show that such manual measurement of latencies is easy and yet sufficiently accurate to be of great clinical value. The latencies of voluntary saccades are normal in peripheral pathology (less than 250 milliseconds). Latencies of voluntary saccades are significantly increased in extrinsic brain stem lesions: tumours (in particular ponto cerebellar tumours), meningitis, head injury; but the velocity of the saccade is normal. This effect goes in parallel with impairement of the smooth pursuit. In intrinsic brain stem lesions (multiple sclerosis, acute brain stem stroke, oculomotor paralysis) latencies are increased bilaterally and above all, there is a significant slowing of the saccade. The role of fatigue increased latencies in some patients of this series. Two populations can be discerned in vestibular neuritis: one normal and one with abnormal smooth pursuit and increased saccadic latencies.
Study of following eye movements (posterior oculogyric pathway) and saccadic eye movements (anterior oculogyric pathway) represents the principal advance in nystagmography in the past ten years. Use as a visual stimulus of the LED bar developed by one of the authors (E.U.) has proved to be clinically easy and gave results identical to those of the reference stimulation system (laser + mobile mirror). It is possible to quantify performance and abnormalities of these two oculogyric pathways using parameters calculated: - either using a micro-computer (Aurelia); - or manually following a technique which the authors describe in detail indicating normal results and limits in their variations. These parameters for the foveal following system are gain and total movement. For the saccadic system, they are the maximum speed of the saccade, latent period and its accuracy. Using such quantitative analysis, it has become possible not only to draw a distinction between peripheral and central disorders, but also to describe different topographical groups: lesion of the cerebellopontine angle, cerebellar lesion, intrinsic lesion of the brain stem or parietal lesion. These different patterns are illustrated by examples.
Experiments were undertaken to test for the stable integration of defined prokaryotic genes in mammalian cells. Thus lambda dvgal 88 plasmid DNA were transferred together with the herpes simplex virus type 1 thymidine kinase (TK) gene as a selectable marker to TK- mouse cells. DNA restriction and hybridization analysis of TK+ mouse cell clone DNA revealed (i) the presence of prokaryotic lambda dvgal 88 sequences in the mouse DNA; (ii) the stable integration of the prokaryotic DNA in mouse cell DNA under selective conditions; and (iii) the presence of lambda dvgal fragments in several copies per cell and their integration at different loci within the cell DNA.
Mild ultraviolet irradiation of Escherichia coli 50S ribosomal subunits causes a cross-linking reaction between protein and RNA, whose primary target is protein L4 [Möller, K., & Brimacombe, R. (1975) Mol. Gen. Genet. 141, 343]. Here we have determined the site of this cross-link both on L4 and on 23S RNA. For the site on the protein, a cross-linked protein-oligonucleotide complex was isolated and subjected to successive digestions with various proteases. In each case the peptide-oligonucleotide complexes formed were analyzed. It could clearly be shown that the cross-link site was contained within a characteristic peptide 16--20 amino acids long and that the amino acid concerned was the tyrosine residue at position 35 in the recently completed L4 sequence (M. Kimura and B. Wittmann-Liebold, personal communication). For the site on the RNA, a cross-linked L4--23S RNA complex was subjected to mild nuclease digestion, producing a range of L4--RNA fragments which were isolated with the help of a new two-dimensional gel electrophoresis system. Oligonucleotide analyses of these fragments, combined with successive nuclease digestions of the residual oligonucleotide attached to protein L4, established that the site of cross-linking was homogeneous, involving a uridine residue at position 615 in the recently determined 23S RNA sequence [Brosius, J., Dull, T. J., & Noller, H. F. (1980) Proc. Natl. Acad. Sci. U.S.A. 77, 201].
Bifunctional reagents, namely bis-(2-chloroethyl)-amine ("nitrogen mustard") and activated esters of 3-(2-bromo-3-oxobutane-1-sulphonyl)-propionic acid ("bromo-ketone reagent") are used to cross-linked protein to RNA within intact ribosomal subunits. The cross-linked proteins are analysed on two different two-dimensional gel electrophoresis sytems, and the existence of a stable cross-linkage is demonstrated by isolating cross-linked protein-oligonucleotide complexes from subunits containing 32P-labelled RNA. Proteins S3, S4, S5, S9/S11 and S13 from the 30S subunit, and proteins L1 and L2 from the 50S subunit were cross-linked to RNA by the nitrogen mustard, together with a number of other so far unresolved proteins. Correspondingly S3, S4, S7, S9/S11 and L12 were cross-linked by the bromoketone reagent, although in lower yield. The reagents should prove useful topographical studies on ribosomal subunits, and arguments are presented favouring the use of non-cleavable and relatively non-specific RNA-protein cross-linking reagents for such studies.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.