Heavy demands at contract time.
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Contract Services↗
Biomedical subjects
E Ulmer
Publications and source records attributed to E Ulmer.
[Rotatory impulse test does not replace caloric tests].
We sought to determine whether the rotatory impulsional test was capable of exploring the canalar function with sufficient precision to replace the caloric test, as it has been recently affirmed. We first compared the observed preponderance from this test with that measured during a sinusoidal (20 and 4 s) test. We observed that, in the case of a significant preponderance for a given test, there was complete redondance with the preponderance observed with any other test. The rotatory impulsional test does not present any specific advantage compared to other kinetic test as far as the observation of the preponderance phenomenon. We then compared the preponderance with the results of the caloric tests and came to the following conclusions i) the absence of preponderance does not allow us to predict the absence of vestibular deficit, due to the fact that 37% of the deficits were compensated for including acoustic neuroma; ii) the presence of a preponderance does not allow a priori to say whether it is of vestibular, cervical, or central origin and systematic caloric tests shows that almost one fourth of preponderance observed is not associated with unilateral weakness iii) supposing that a clinical argument allow us to conclude as to the probable vestibular origin of a vestibular preponderance, the direction of this preponderance does not allow us to determine which side is involved. In fact, if the undercompensated deficits are 3 times more frequent than overcompensated deficits, the proportion of preponderance not linked to a significant deficit indicates that the probability of encountering a preponderance related to a specific undercompensated deficit is approximately 50%. We thus did not find in the rotatory impulsional test any specific advantage allowing us to predict the laterality of a vestibular lesion.
Caloric Tests↗
3-D eye movement measurements on four Comex's divers using video CCD cameras, during high pressure diving.
Previous studies have shown the vulnerability of the vestibular system regarding barotraumatism (1) and deep diving may induce immediate neurological changes (2). These extreme conditions (high pressure, limited examination time, restricted space, hydrogen-oxygen mixture, communication difficulties etc.) require adapted technology and associated fast experimental procedure. We were able to solve these problems by developing a new system of 3-D ocular movements on line analysis by means of a video camera. This analyser uses image processing and forms recognition software which allows non-invasive video frequency calculation of eye movements including torsional component. As this system is immediately ready for use, we were able to realize the subsequent examinations in a maximum time of 8 min for each diver: oculomotor tests including saccadic, slow and optokinetic traditional automatic measurements; vestibular tests regarding spontaneous and positional nystagmus, and reactional nystagmus to the pendular test. For pendular induced nystagmus we used appropriate head positions to stimulate separately the lateral and the posterior semicircular canal, and we measured the gain by operating successively in visible light and complete darkness. Recordings were done during a simulated onshore dive to an ambient pressure corresponding to a depth of 350 m. The above examinations were completed on the first and last days by caloric tests with the same video system analyser. The results of the investigations demonstrated perfect tolerance of the oculomotor and vestibular systems of these 4 divers thus fulfilling the preventive conditions defined by Comex Co. We were able to overcome the limitations due to low cost PC computer operation and cameras (necessity of adaptation to pressure, focus difficulties and direct light exposure eye reflexions). We still have on line accurate measurements even on the torsional component of the eye movement. Due to this technological efficiency we also present some mathematical aspects of the software.
Adult↗
On the role of the olivocochlear bundle in hearing: a case study.
A young patient with normal pure-tone thresholds in both ears underwent a unilateral vestibular neurotomy in January 1992 to relieve severe vertigo ascribed to Ménière's disease. Evidence is provided that the whole vestibular nerve including the olivocochlear bundle (OCB) was sectioned. Just prior to the surgery, the patient was examined in several psychoacoustic tests involving mainly signal detection and selective attention. Over the next 20 months, he was reexamined in those same tests. The patient's ability to detect expected tones in the quiet (including audiograms) or in noise was the same as before the surgery. The one change was a marked improvement in the detection of unexpected signals in noise, which appears to reflect impaired selective attention. During those 20 months, new tests were also performed on discrimination, loudness, pitch, lateralization, and temporary threshold shift. On these tests, the only differences between the operated and unoperated ears concerned binaural diplacusis and loudness adaptation close to threshold, but these differences may well have been present prior to the surgery. Except with respect to what is probably selective attention, we uncovered no other clear role for the OCB in hearing. This outcome agrees with limited measurements on other patients, with their subjective reports, and with a number of published neurophysiological observations.
Acoustic Stimulation↗
[Otologic manifestations of the pain dysfunction syndrome of the stomatognathic system].
Phylogenesis, ontogenesis and anatomy explain the close relationship between temporo-mandibular joint and the middle ear and can therefore help understanding otologic symptoms such as: otalgia which often correspond to articular and muscular pain irradiation (coming from sterno-cleido-mastoid, lateral and medial pterygoid, deep layer of the masseter and temporal muscles); acouphens and ear block sensation that could be caused by a spasm extension of the manducatory (i.e. medial pterygoid) to levator and tympani tensors. These three muscles, which originate from the first branchial arch, have a proprioceptive sensitivity and share the same innervation. What is more tensor and levator veli exchange certain muscular fibers. Tensor tympani spasm can be held responsible both for a decrease or abolition of the Klockhoff's reflex, together with a decrease of the stapedian reflex, the latter due to tympani rigidity induced by a spasm of the tensor tympani.
Ear Diseases↗
[Vestibular compensation. Clinical value of its dynamic study].
Vestibular compensation consists of all the processes of neurological reorganization that allow recovering balance after a unilateral vestibular lesion. According to its etiology, the peripheral lesion may be more or less severe, may evolve more or less rapidly, and be more or less reversible. Therefore, it will have a characteristic "pattern" in time, which enables us to classify the kinetic aspects of peripheral pathology. Vestibular compensation, which responds to these variations in the sensitivity of the posterior labyrinth, is a slowly progressive adaptation mechanism. This compensation will progressively reduce the musculotonic asymmetry affecting the postural muscles and the eye muscles, and it can therefore be studied on the basis of the velocity of the spontaneous nystagmus as measured in the dark. We can then define a "vestibular compensation rate" at a given moment. To achieve this, a diagram (E. UMER) is proposed to represent the lesion and the rate of vestibular compensation and to study their mutual relationships. The dynamic study of vestibular compensation and the measurement of its "time constant" than have threefold merits for diagnosis, prognosis and treatment.
Adaptation, Physiological↗
[Otospongiosis: different surgical technics, identical results. Why?].
Both platinectomy and platinotomy are currently used to treat otosclerosis surgically. Though the techniques are different from one another, especially by the new area ratio between tympanic membrane and stapes foot-plate, the results are similar. It should be clear that the simple "piston model" of the tympanic ossicular system cannot explain this results. If, for the seesaw mechanical view, a vibratory molecular system conducting acoustic energy is substituted, a pertinent explanation can be given for this result. Thus, understanding of the pattern motion of the tympanic ossicular system has to change drastically.
Ear, Middle↗
[Diagnostic and therapeutic problems in dissociated forms of Menière's disease].
The authors report the cases of 5 subjects who presented with incapacitating vertigo which was attributed to a dissociated form of Meniere's disease. They stress the difficulty, in these circumstances, in making a precise diagnosis which can only in fact be confirmed with the benefit of a longer follow up. They stress the value of systematically combining frequency analysis with measurement of maximal slow phase velocity during vestibular testing. This allowed better precision in terms of topographical diagnosis. All subjects underwent vestibular neurotomy via the retro-sigmoid approach. The procedure did not alter hearing and compensation occurred within the usual delay. The question therefore arises as to when is the best time to intervene in patients presenting with vertigo of peripheral origin with preserved hearing.
Audiometry↗
Low circulating vitamin D in obesity.
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.
Adult↗
Isolation and characterization of coliphage omega 18A specific for Escherichia coli O18ac strains.
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.
Antigens, Bacterial↗
[Various treatment possibilities in damaged anterior and canine teeth (I)].
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Adult↗
[Various treatment possibilities in damaged anterior and canine teeth (II)].
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Adult↗
[Measurement of the latencies of voluntary and corrective ocular saccades. Value in otoneurology].
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.
Brain Diseases↗
[Equipment and technic allowing a quantitative study of pursuit eye movements and saccadic movements].
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.
Electronystagmography↗
[Biochemical evidence for integration of prokaryotic DNA into mammalian cells (author's transl)].
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.
Animals↗
Precise localization of the site of cross-linking between protein L4 and 23S ribonucleic acid induced by mild ultraviolet irradiation of Escherichia coli 50S ribosomal subunits.
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].
Amino Acid Sequence↗
Chemical cross-linking of protein to RNA within intact ribosomal subunits from Escherichia coli.
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.
Butanones↗
The dentist and the patient. Restoration of a severely devastated mandibular dentition after the elimination of all focal infections and periodontal inflammation.
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Denture, Partial, Removable↗