Biomedical subjects
K Karlsen
Publications and source records attributed to K Karlsen.
[Cranio-mandibular pathosis in a group of patients at a university clinic].
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[Causes for failure/complications in restorative treatment with large fixed bridges].
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Highly sensitive immunoadsorption procedure for detection of low-abundance proteins.
A procedure that virtually eliminates nonspecific adsorption of radiolabeled proteins during immunoprecipitation was devised utilizing staphylococcal cells containing protein A (Staph A). Immunoprecipitates (antigen-antibody complexes) were solubilized from Staph A pellets into detergent micelles by incubation in a small volume of 1% sodium dodecyl sulfate (SDS) at 23 degrees C for 10 min. To allow re-formation of immunocomplexes and rebinding to new Staph A, the SDS-solubilized material was diluted 20-fold in buffer containing 1% Triton X-100 and 0.5% sodium deoxycholate. Specific conductance measurements revealed that this solubilization and subsequent reimmunoadsorption of antibody-antigen complexes occur at SDS concentrations that are first above and then below its critical micelle concentration. This procedure lowered the nonspecific background from approximately 2250 parts per million (ppm) to less than 25 ppm with a final recovery of 30-50% depending on the antigen and antibody. Chaotropic agents such as 2 M urea, 0.2 M KOH, and 3.5 M MgCl2 (as well as combinations of urea and SDS) can substitute for 1% SDS, although the final recovery is somewhat lower. Fluorography of radiolabeled proteins obtained in this manner displays virtually undetectable background even for exposures as long as 2 months. These methods allowed the unambiguous detection of low-abundance antigens at a high level of sensitivity, for example, mouse mammary tumor virus protein products and epidermal growth factor receptor.
A distinct glucocorticoid hormone response regulates phosphoprotein maturation in rat hepatoma cells.
Glucocorticoid hormone-dependent maturation of the mouse mammary tumor virus (MMTV) phosphorylated polyprotein (Pr74) allows experimental access to certain posttranslational regulatory circuits under steroid control in M1.54 cells, an MMTV-infected rat hepatoma cell line. Pulse-chase experiments revealed that [35S]methionine-labeled Pr74 synthesized in uninduced cells could be converted posttranslationally into p24, a stable phosphorylated maturation product, only after 4 h of exposure to 1 microM dexamethasone, a synthetic glucocorticoid. This regulated processing could be prevented by prior exposure, during the chase period, to inhibitors of RNA (actinomycin D) or protein (cycloheximide or puromycin) synthesis. Moreover, half-maximal production of p24 occurred at 10 nM dexamethasone, a concentration that approximated half-maximal receptor binding and stimulation of MMTV transcript synthesis. Kinetic, hormonal, and genetic evidence suggest that p24 expression did not require or result from the overall glucocorticoid-dependent increase in polyprotein concentration. First, 20 h after dexamethasone withdrawal, Pr74 maturation was completely deinduced, whereas the absolute level of this MMTV precursor remained 10-fold over its basal level. Second, progesterone, which competes with dexamethasone for receptor binding, facilitated the regulated production of p24 but prevented the steroid-mediated accumulation of functional MMTV mRNA. Lastly, certain glucocorticoid-responsive variants, derived from M1.54 cells by resistance to complement cytolysis, expressed p24 in the presence or absence of glucocorticoid-induced levels of Pr74. Taken together, our results suggest that the glucocorticoid-regulated maturation of MMTV phosphopolyproteins resulted from an independent hormone response that required normal receptor function and de novo RNA and protein synthesis.
Effects on retention of reducing the palatal coverage of complete maxillary dentures.
Twenty patients with complete dentures in both jaws gave up their maxillary ones for experimental purposes for 4 weeks while new dentures were made. The experimental dentures were reduced palatally to a new U-shaped border situated approximately 10 mm from the dental arch. Denture retention, defined as the ability of a denture to remain seated on the supporting tissues under various conditions, was measured as resistance towards cranially directed tilting loads, using a miniature bite force recorder. Dislodgement-provoking loads were applied to the first bicuspid on both sides and to the central incisors. The retention measurements were performed before and immediately after reduction of the palatal coverage and, finally, after 4 weeks. Interview questions were posed concerning the subjects' experience of denture retention and some other aspects of oral comfort. The interviews were carried out before reduction of the palatal coverage and after 2 and 4 weeks. The results of the experimental dislodgement tests suggested that the ability to withstand tilting loads was insignificantly altered by reduction of the palatal coverage. This finding was in agreement with responses indicating that retention during meals remained unchanged. However, several individuals reported that denture retention between meals was impaired. Three denture wearers reported that reduction of the palatal coverage influenced their sense of taste positively, and one reported that an occasional gagging tendency had disappeared. At the end of the experiment the participants were given the choice of a new conventional denture or a new denture without palatal coverage.(ABSTRACT TRUNCATED AT 250 WORDS)
Pathologic attrition and maximal bite force.
The maximal bite force was recorded between antagonizing anterior teeth in a group (n = 10) of patients with pathologic attrition and in a control group. No statistically significant difference between the maximal bite forces was recorded. Also, the effect on the maximal bite force of the continuous wearing of a partial bite raising splint for 4 months was recorded. The great individuality in reaction patterns prohibited simple generalizations. However, in some individuals the maximal bite force was larger when biting on the splint than without, both at base line and after 4 months. Also, the maximal bite force showed a tendency to increase with time. The findings indicate that pathologic attrition is not necessarily associated with a high maximal bite force. Also, the maximal bite force recorded under various conditions is seemingly not an absolute value but rather the result of a number of factors of varying importance for different individuals.
The effect of denervation on trauma from occlusion.
Trauma from occlusion was induced by inserting cantilever bridges bilaterally in the mandibles of two monkeys. In one monkey the mandibular nerve was cut on one side; in the other on both sides. By this procedure possible protective action of nerve receptors in the periodontal membrane was reduced. The occlusal trauma resulted in severe damage to the pulp and resorption of the roots, but no appreciable downgrowth of the crevicular epithelium.
Evaluation of endosseous implant abutments as a base for fixed prosthetic appliances. A preliminary clinical study.
In the present 2-year report nineteen Linkow blade implants with a total of twenty-seven perforating posts were assessed. All implants included were considered functionally successful and served as abutments for fixed prosthetic appliances. Periodontal probe and radiographic measurements of bone loss around the perforating implant posts, and registration of plaque and gingival index scores were performed every 6 months. During the first 4-6 weeks after implantation a vertical bone loss approximating an average of 1-2 mm occurred in the neck area of the implants. After this initial resorption, bone loss proceeded at a slower rate. The mean annual crest reduction was approximately 0.1 mm from the first to the fourth examination, as assessed from radiographic measurements. Periodontal probe measurements, showing a mean annual crest reduction of 0.2 mm, usually exhibited higher values than corresponding radiographic measurements at both implants and abutment teeth. At implants there was a significant positive correlation between plaque and gingivitis after 18 and 24 months, but not before that time. No correlation was seen between gingival index scores and the degree of bone resorption.
Trauma from occlusion in monkeys.
Traumatic occlusion was induced in monkeys by insertion of bridges raising the bite. Both incisors and molars were used as abutments. Observation periods ranged from 7 to 24 months. No appreciable effect of the trauma on the apical proliferation of the crevicular epithelium was found. The results were the same in monkeys with or without marginal gingival inflammation before the trauma was induced.
Ostby's institute.
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Frequency and location of artificial crowns and fixed partial dentures constructed at a dental school.
The material consists of patients who received single crowns and fixed partial dentures at the Department of Prosthetics, Dental Faculty, University of Oslo in the period 1967-73. Two-thirds of the patients were women, and about two-thirds of the restorations were made in the maxilla. A total of 3275 crowns were received by 2145 patients. On average, maxillary teeth were crowned 7 years earlier than mandibular teeth. A total of 1393 fixed partial dentures, consisting of 6835 units, were made for 1368 patients.
An alternative treatment in cases with advanced localized attrition.
A combined orthodontic/prosthetic treatment of patients with advanced localized attrition has been described. In one patient the effect of the orthodontic treatment upon the morphological face height has been studied using an X-ray cephalographic technique and the results have been discussed.
[Construction proposals for vitallium prostheses].
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[Maximum oxygen uptake in young Norwegian men].
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Traumatic occlusion as a factor in the propagation of periodontal disease.
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Gingival reactions to dental restorations.
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The interface between dentine and irregular secondary dentine.
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