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Biomedical subjects

M Bergman

Publications and source records attributed to M Bergman.

At least 181 records · Page 10Linked to original sources
PubMed1979

Bone conduction changes following successful tympanoplasty type I.

Pre and one year postoperative bone conduction (b.c.) thresholds were compared for 50 ears of 48 patients, ranging in age from 14 to 42 years, in whom successful tympanic grafts resulted in at least an average improvement of 10 db for 500 to 4000 Hz. While pre and postoperative data are included for all ears and test frequencies, significant BC improvement is seen only at those frequencies, in each case, where the pre-op BC thresholds were worse than 10 db. Normal pre-op BC thresholds cannot show substantial improvement because of audiometric limitations. The amount of BC shift at each frequency for those with pre-op BC thresholds that were subnormal averaged 6 db at 500 Hz, 13.3 db at 1000 Hz, 13.8 db at 2000 Hz and 9 db at 4000 Hz, all highly significant statistically. There were no significant postoperative BC shifts related either to duration of the disease process, length of postoperative period before final test (all were more than one year) or whether the surgical procedure was tympanoplasty type I or myringoplasty.

Adolescent↗
PubMed1978

Potential and polarization measurements in vivo of oral galvanism.

Galvanic currents within the oral cavity may have harmful effects on biological tissues. In the present work 16 patients with different kinds of oral and other discomfort and pain which they attributed to oral galvanism were investigated. The potential and polarization of each metal restoration within reach of a platinum probe were measured versus a reference electrode. A recording of these measured values permits a calculation of the currents which may pass between the teeth. A control group of patients with no subjective symptoms of galvanism in the oral cavity was also investigated. The results of the electrochemical measurements showed that conditions for oral galvanism existed within the individuals of the patient group as well as within the control group. One remarkable observation was that the metallic restorations often consisted of different electrically isolated areas with different electrochemical properties. This and other factors influencing oral galvanism are discussed.

Adult↗
PubMed1978

Powder data file as a tool for identification of dental gold alloys.

In order to obtain data for a prospective powder data file for dental gold alloys X-ray diffraction photograms of 75 different gold alloys were taken using a Guinier-Hägg camera and CuKalpha1 radiation. Before the X-ray photograms were taken the alloys had been heat treated at 700 degrees C, 800 degrees C or 900 degrees C depending on the solidus temperatures of the alloys. The lattice parameters of the samples were determined from the X-ray photograms. These data were supplemented by a specification of the interplanar spacings of the three strongest lines on the diffraction patterns and also by the relative intensities and Miller indices of these lines. An extensive library of reference films is to be collected and this and other details of the file are discussed. It is not intended that the file be used to identify a particular alloy but merely to identify the type of alloy. Thus it can serve as a guide to facilitate the proper selection of gold alloys within practical clinical dentistry.

Filing↗
PubMed1977

Dissolution and uptake of cadmium from dental gold solder alloy implants.

Pure metallic cadmium was irradiated by means of thermal neutrons. The irradiated cadmium (115Cd) was placed in bags of gold foil and the bags were implanted subcutaneously in the neck region of mice. Two and 3d respectively after implantation the mice were killed, the bags removed and the animals subjected to whole-body autoradiography. The autoradiograms revealed an uptake of 115Cd in liver and kidney. In another experiment specimens of a cadmium-containing dental gold solder alloy, a cadmium-free dental casting gold alloy and soldered assemblies made of these two alloys were implanted subcutaneously in the neck region of mice. The animals were killed after 6 months; cadmium analysis showed significant increases in the cadmium concentration in liver and kidney of those mice which had been given implants of gold solder alloy. The study clearly shows that due to electrochemical corrosion cadmium can be released from implants and accumulated in the kidneys and the liver.

Animals↗
PubMed1977

The effects of message speed on auditory comprehension in patients with cerebral cranial injury.

A brief preliminary report is presented on the effects of varying the speed of a spoken message on the performance of motor tasks by patients with cerebral cranial injury. The token test for aphasia was recorded at three different speech time compression/expansion ratios, then presented under sound field (loudspeaker) conditions to three groups of subjects, one of normal young adults as a control, the second of patients with cerebral cranial injury without evidence of aphasia, and the third containing CCI patients with aphasia. Results are reported for speech speed increases (compression) of 25% and 50% and for a speed decrease (expansion) of 35%.

Aphasia↗
PubMed1977

Tests of auditory perception in the assessment and management of patients with cerebral cranial injury.

Special listening tests have been applied to patients with cerebral cranial injury to determine whether such tests of auditory performance will provide functional evidence of lesions which are difficult to examine physically. There have been many reports in the literature on the apparent relationship between lesions affecting portions of the central auditory nervous system and results on tests of auditory perception for speech which is either distorted in some way or presented in competing arrangements to the two ears. The premise is that these tests require integrative function of the brain while reducing the effects of conditions of the peripheral organ of hearing and of basic language functions such as symbolization and memorization. Much of the previous literature has been concerned with infiltrative lesions, such as tumors. Our rehabilitation facility serves a number of patients whose lesions are the result of injuries rather than growths or vascular accidents. The present study was undertaken, therefore, to explore the contribution of information derived from such test procedures to diagnosis and to the planning of individual programs of rehabilitation. Preliminary findings are presented for a series of patients with cerebral cranial injury.

Auditory Perception↗
PubMed1976

Age-related decrement in hearing for speech. Sampling and longitudinal studies.

A 10-year study was conducted in which 282 adults in age decades of 20 through 80 were tested in a comprehensive battery of tasks requiring the perception of speech under a variety of conditions in which the speech signal was degraded. The original results were plotted to reveal the differences in performance of the population samples of each decade. In follow-up studies, after 3 years and again after 7 years, samples of the original subject population were retested. The results of the first, stratified sampling and of the longitudinal studies are compared. The two most apparent trends are: (1) the perception of degraded (distorted and competed) speech undergoes a noticeable decline beginning with the 5th decade of life, and (2) the decline is sharply steeper in the 7th decade.

Adolescent↗
PubMed1975

Dissolution rate of cadmium from dental gold solder alloys.

The dissolution rate of cadmium from six different dental gold solder alloys was determined in an in vitro potentiostatic study. The measurements were made in the potential range 740--880 mV and attempts have been made to extrapolate the results to a potential region that might in reality occur in the oral cavity. For comparison the dissolution rates of copper and zinc were also determined. Electrochemically the most interesting quantity was the logarithm of the dissolution rate because it is a linear function of the applied potential. This linear relationship was given by the Tafel equation. The dissolution rate of cadmium was shown to be rather small even under circumstances which may be said to represent very unfavourable conditions within the oral cavity.

Cadmium↗