Biomedical subjects
Publications and source records attributed to K Muller.
In 1976 the hollow cylinder implant was introduced. A number of articles have been published about the ITI implant system. In this article, short-term results of 102 ITI F-type implants in 40 patients are reported. The results showed this one-stage implant to be at least comparable to other well-known implant systems.
Seventeen myasthenia gravis and seven control patients were studied mechano (MMG)- and electromyographically (EMG) during isoflurane/oxygen/air anaesthesia. In myasthenic patients the mean train-of-four ratio and neuromuscular block (by MMG) during 1.9 MAC isoflurane anaesthesia were 55 +/- 9% and 46 +/- 12%, respectively. The correlation between simultaneous MMG and EMG measurements was excellent (r2 = 0.933, P less than 0.001). The occurrence of HLA-B8 together with acetylcholine receptor antibodies seems to predispose myasthenic patients to a neuromuscular depression produced by isoflurane. Our current and prior results show that isoflurane possesses approximately twice as strong a neuromuscular blocking effect as halothane in myasthenic patients.
1 alpha,25-dihydroxycholecalciferol (1,25(OH)2D3) inhibits the lymphocyte growth hormone, interleukin 2. Since its production is dependent upon interleukin 1 (IL-1) produced by antigen-presenting cells, we tested five vitamin D3 analogues for effects on the production and function of human natural and recombinant IL-1. The production was not affected, but 1,25(OH)2D3 (greater than 10(-11) M) and a synthetic derivative MC 903 (greater than = 10(-10) M) inhibited the proliferation of mouse thymocytes to IL-1. The vitamins failed to affect the cytotoxic activity of tumor necrosis factor. 1,25(OH)2D3 may play a physiological immunomodulatory role as a selective inhibitor of the function of IL-1, and MC 903 may prove clinically useful in this regard because of its limited calcium metabolic activity.
An analysis of proliferating cell subsets in the allogeneic mixed lymphocyte culture (MLC) in adults (n = 19) and newborns (n = 12) was performed by a method combining immunoperoxidase staining and autoradiography. The main cell type responding in adult cells were OKT8-positive (38%), whereas in neonates OKT4-positive cells (31%) predominated. Furthermore, in the neonatal allogeneic MLC there were significantly more 3H-thymidine incorporating Leu 12-positive B cells than in adults (12% vs 4%).
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In oligomeric proteins, the native conformation and its functional properties depend on the interactions which exist between the different chains. The role of these subunit interactions can be studied using either the unfolded state or the native state as a starting point. During the folding process, the properties which appear following a bimolecular reaction are related to the formation of an association area. Similarly, the properties which are lost upon partial dissociation of the native state are related to the association area which is disrupted. Four examples are presented in this article: phosphofructokinase and aspartokinase-homoserine dehydrogenase from E. coli are studied through their folding process, and fatty acid synthetase from B. ammoniagenes and reptilian ovomacroglobulin are studied through their dissociated forms. In all cases, the function of the protein is a sensitive index of the formation of the subunit interactions, and can be more conveniently measured than other size/shape parameters. The extrapolation from the folding of small proteins to the assembly of large and complex structures can be reasonably achieved by admitting that subunit interactions are coupled to the subtle adjustments required by the protein to exert its biological function.
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Two infants with malignant osteopetrosis were treated by allogeneic bone-marrow transplantation after marrow ablation with busulphan and cyclophosphamide. Engraftment without graft-vs-host disease occurred in both cases. The first child established stable chimerism and is clinically well 30 months after receiving a histocompatible sibling bone-marrow graft: haematological, radiological, and biochemical features of osteopetrosis have completely resolved. The second child was non-identical with the marrow donor (his older sister) at a single HLA-B locus and received cyclosporin A as prophylaxis for graft-vs-host disease. 11 months after transplantation haematological abnormalities have resolved and radiological features have improved. The findings indicate that allogeneic bone-marrow transplantation should be considered the treatment of choice for infants with severe osteopetrosis who have histocompatible siblings.
The serum of pigs developing atherosclerosis is deficient in the ability to stimulate the migration of Balb/c-3T3-A31 cells in culture. This deficiency appears to be due to the presence of an inhibitor located in lipoprotein-free serum. The migration assay was used to follow the changing migration activity of the serum of pigs on a changing diet.
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1. Treatment of rats with hypolipidemic drugs elicited an increase in oleic and a decrease in linoleic acid content in cholesterol esters, triglycerides and phospholipids of serum and liver lipids. 2. The change was most pronounced in triglycerides followed by cholesterol esters and phospholipids. 3. The shift was dose-dependent, starting with doses eliciting hypolipidemic effects. 4. The shift became obvious immediately after beginning of treatment and reached after 4 days a new steady state. 5. This effect was shared by both drugs of aryloxy fatty acid structure, but was not seen with either L-thyroxine or nicotinic acid. 6. The mechanism underlying this phenomenon is thus far unknown, but in our view it merits further attention.
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This study evaluated the effect of sulfuric acid aerosol exposure for 2 consecutive days on seven human biochemical blood parameters. A total of 20 human subjects were exposed to 100 micrograms/m3 (0.033 microM) sulfuric acid aerosol (0.5 microns mean mass diameter) for 4 hr/day for 2 consecutive days. A total of 17 human subjects were exposed to 4 hr of ambient air on both exposure days. The chemical blood parameters were measured pre- and post-exposure, and 20 hr after the second exposure: serum glutathione, red blood cell glutathione reductase, red blood cell glucose-6-phosphate dehydrogenase, lysozyme, serum glutamic oxaloacetic acid transaminase, serum vitamin E, and 2, 3-diphosphoglycerate. The results indicate no significant response in any of the seven biochemical blood parameters measured. At this level, repeated exposure did not over-burden the upper airway defenses against acid aerosol.
The biological response to controlled exposures of nitrogen dioxide (NO2) was studied in 19 human subjects exposed to 0.2 ppm NO2 for 2 hr and compared to 15 control subjects exposed to filtered air for 2 hr. Seven biochemical blood parameters, including glutathione, red blood cell glutathione reductase, 2,3-diphosphoglycerate, methemoglobin, vitamin E, complement C2, and IgA were measured prior to exposure, immediately after exposure, and 22 hr following exposure. The only variable that showed significant change due to NO2 exposure was glutathione. Glutathione is known to protect the erythrocyte from oxidative stress. The increase in glutathione observed upon exposure to NO2 may be a protective reaction of the erythrocyte to meet the oxidative stress.
A follow-up study of slow cortical potentials in children with elevated blood lead (PbB) histories was conducted two years after initial evaluation. An age x PbB interaction was again observed wherein slow wave (SW) voltage varied as a linear function of PbB with the slope of the function dependent on age. The linear relationship of SW voltage and PbB was significant using either original PbB values, (14-55 micrograms/dl), follow-up values (11-39 micrograms/dl), or the mean of the two PbB values. No evidence of a threshold for this effect was observed. The similarity of results obtained at initial and follow-up assessments suggests that the observed alterations in CNS function are persistent, despite a significant decrease in mean PbB across time. The observed change in SW voltage at PbB levels previously considered to be harmless suggests the need to reconsider the currently accepted 30 micrograms/dl threshold for undue lead absorption in children.
This study evaluated the effect of a single exposure to sulfuric acid aerosol on six human biochemical blood parameters. A total of 18 human subjects were exposed to ambient air for 4 hr on the first day of exposure and to 100 microgram/m3 (0.033 microM) sulfuric acid aerosol (0.5 micrometer mean mass diameter) for 4 hr on the second day. A total of 17 human subjects were exposed for 4 hr to ambient air on both exposure days. On each exposure day, at 30 min and 90 min after exposure was initiated, all subjects engaged in a 15-min exercise period (walking 4 mph on a treadmill inclined at 10 degrees). Six biochemical blood parameters were measured before and after exposure: glutathione, lysozyme, glutathione reductase, serum glutamic oxaloacetic acid transaminase, serum vitamin E, and 2, 3-diphosphoglyceric acid. The results indicate no significant effect of one 4-hr exposure of humns to 100 microgram/m3 sulfuric acid aerosol. One significant post-exposure effect did occur--an increase in glutathione reductase--for both the control and acid-exposed group. It is concluded that at the levels studied, sulfuric acid aerosol is neutralized in the upper airways; consequently, no cellular damage is measurable.