Biomedical subjects
Publications and source records attributed to S Karlsson.
The phenotypes of red cell glyoxalase I (GLO) were determined in two Icelandic population samples using starch-gel electrophoresis and high-voltage agarose-gel electrophoresis. The gene frequencies of 178 individuals were 0.46 for GLO1 and 0.54 for GLO2. In a group of Icelandic insulin-dependent diabetics the gene frequencies were found to be very similar. The evaluation of 30 mother-child pairs is also shown.
A series of 106 patients with uterine or adnexal lesions is presented. Bilateral selective internal iliac angiography proved to be valuable in the preoperative diagnosis of gynecologic tumors regarding their origin and in the differential diagnosis between malignant and benign tumors.
Angiography was performed before and after intraarterial administration of prostaglandin F2 alpha, 8-lysine vasopressin, oxytocin, methylergometrine, noradrenalin, and bradykinin in 62 women with various pelvic tumors. It is concluded that the use of the vasoactive drugs in the doses tested did not improve the angiographic diagnosis in unselected cases of female pelvic tumors.
Selective catheterization of the ovarian artery was performed in 39 women with pelvic tumor. Previously the combination of ultrasound and bilateral selective internal iliac angiography was proven to be valuable in the evaluation of gynecologic lesions. The present series demonstrates that selective ovarian angiography still enhances the possibilities for a correct preoperative diagnosis.
Mandibular movements in wearers of complete dentures were registered before and after rehabilitation with new dentures by light-emitting diodes (LEDs). The duration of the opening, closing and occlusion phases as well as the whole chewing cycle were studied. The closing phase had the longest duration of the three phases, 0.36 s, and represented 45% of the duration of the total chewing cycle. Only minor changes in the movement pattern were found when comparing different test-foods and after rehabilitation with new dentures.
Fifty patients presenting an abdominal mass was investigated with ultrasonography as the first examination. In 5 patients no mass was found by ultrasonography and repalpation revealed no abnormal findings. Of the 45 patients with a mass, ultrasound verified the mass in 43 patients (96%) and a correct origin of the mass was found in 41 patients (91%). The exact nature of the lesion was diagnosed in 32 patients (71%). In 2 patients ultrasonography was falsely negative
Mandibular chewing movements of 10 young adults were registered with LED. The registrations were performed manually, and the following observations were made: 1. The mean cycle duration was reduced from 1.12 seconds for cycle 1 to 0.76 second for cycle 16. 2. The duration of the opening phase appeared to be shorter than that of the closing phase. 3. The maximal vertical movement of the mandible decreased throughout the chewing period. The results obtained in this study agree with those reported by other investigators and indicate that a system using LED is suitable for analyzing the mandibular movement pattern in clinical situations.
A study was made on four patients to determine the reproducibility of the outer form of the buccal and lingual flanges of a complete lower denture as developed by functional movements of the surrounding tissues. 1. Two dentists participated in the study to find out the operator effect when making impressions for the functional form of the flanges. 2. Two tissue-conditioning impression materials were used to determine if the characteristics of the impression material had any effect on the final form. 3. The impression materials were applied to the denture flanges by two different methods. 4. The impressions were placed in a mitre box, stabilized with plaster, and sectioned in the molar, premolar, and incisor regions. This provided five cut surfaces for measuring. 5. Each section was measured at five to six representative distances. 6. The differences in the flange form measurement and the distances among the impressions made with the same technique and material were small, and the reproducibility can be considered clinically acceptable. 7. There were statistically significant differences in the flange form measurement distances among the different materials and method of application of the material.
The combination of angiography, ultrasound and fine-needle aspiration biopsy proved to be valuable in the preoperative evaluation of patients with a palpable mass. With ultrasound, the size, shape and origin of tumors exceeding 4 to 5 cm in diameter were correctly diagnosed, whereas angiography differentiated bettter between malignant and benign tumors.
Using cineradiographic equipment with 35 mm film, the application of cineradiographic technique in odontology has been investigated with special reference to observation of bolus-position, the mandibular movement pattern, chewing velocity and the stability of full dentures. The study is divided in two parts. In the first part an assessment is made of the theoretical and practical error of the method and the radiation dose is determined. In the second part limited studies are performed on test-subjects before and after different types of oral rehabilitation. The mathematically estimated geometrical errors almost coincided with the results of the clinical test of the distortion and, together with the tracing error, were of such magnitude that high precision measurements were not possible. By using metal indicators the error could be reduced and movements or differences in the X-ray film greater than 1 mm could be observed with good accuracy. The absorbed dose was determined using the method of thermoluminescent dosimetry and was found to be approximately 5 rad for a cineradiographic investigation of the cranium. The studies of bolus position, mandibular movements etc. revealed, that after oral rehabilitation the patient's oral behaviour may change dramatically. New occlusal surfaces were in most cases used for mastication after a short period of adaptation after rehabilitation. The mandibular movement pattern was also markedly influenced. It is concluded that cineradiography is very suitable for observations of intra-oral behaviour, such as bolus position, and for functional movement analyses. For high-precision measurements other methods should be used.
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In order to evaluate an opto-electronic system for recording mandibular movement a simulator and clinical pilot study was performed. The method was based on light emitting diodes (LED) and a photodetector system. One LED was placed intraorally and one on the forehead, the latter acting as reference. When the light spot is focused on the detector surface a photo-current will occur. This current can be used to obtain two signals linearly related to the x and y coordinates of the LED. By using two detectors the three-dimensional coordinates of a movement can be calculated, consequently also the z-coordinate. In the simulator experiment the method was shown to have a satisfactory precision and good reproducibility. The results from the clinical test indicated that it is possible to measure and record mandibular movement with a minimum of external influence to the test person.
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Explore the source record for details and available documents.