Percutaneous transluminal coronary angioplasty in patients aged > or = 90 years.
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Aged↗
Biomedical subjects
M Kern
Publications and source records attributed to M Kern.
Sandblasting and silica coating of a glass-infiltrated alumina ceramic: volume loss, morphology, and changes in the surface composition.
Silica coating can improve bonding of resin to glass-infiltrated aluminum oxide ceramic (In-Ceram), and sandblasting is a pretreatment to thermal silica coating (Silicoater MD system) or a tribochemical coating process (Rocatec system). This study evaluated the effects of sandblasting and coating techniques on volume loss, surface morphology, and surface composition of In-Ceram ceramic. Volume loss through sandblasting was 36 times less for In-Ceram ceramic compared with a feldspathic glass ceramic (IPS-Empress), and sandblasting of In-Ceram ceramic did not change its surface composition. After tribochemical coating with the Rocatec system, a layer of small silica particles remained that elevated the silica content to 19.7 weight percentage (energy-dispersive spectroscopy). Ultrasonic cleaning removed loose silica particles from the surface and decreased the silica content to 15.8 weight percentage, which suggested firm attachment of most of the silica layer to the surface. After treatment with the Silicoater MD system, the silica content increased only slightly from that of the sandblasted specimen. The silica layer created by these systems differs greatly in both morphology and thickness, which could result in different bond strengths. Sandblasting of all ceramic clinical restorations with feldspathic glass materials should be avoided, but for In-Ceram ceramic the volume loss was within an acceptable range and similar to that of noble metals.
Aluminum Oxide↗
Influence of water storage and thermal cycling on the fracture strength of all-porcelain, resin-bonded fixed partial dentures.
The purpose of this in vitro study was to evaluate the influence of water storage and thermal cycling on the fracture strength of two designs of all-porcelain, resin-bonded fixed partial dentures made with the glass-infiltrated alumina ceramic In-Ceram. Forty frameworks of In-Ceram ceramic veneered with Vitadur-N porcelain were made to replace an upper central incisor bonded to extracted natural teeth. In 20 of the restorations the pontic was veneered only labially with Vitadur-N porcelain and no proximal box preparations were made (design A). The other 20 restorations had additional box preparations proximal to the pontic and the In-Ceram ceramic pontic framework was shifted to the labial aspect and veneered circumferentially with Vitadur-N porcelain (design B). Subgroups of 10 restorations were stored for 7 days in thymol solution or alternatively for 150 days in artificial saliva with thermal cycling for 18,750 cycles between 5 degrees and 55 degrees C. Restorations with design B had a statistically significantly higher fracture strength than restorations with design A. Storage in artificial saliva with thermal cycling significantly reduced the fracture strength of the resin-bonded In-Ceram fixed partial dentures. Therefore, the long-term clinical behavior of resin-bonded In-Ceram fixed partial dentures must be evaluated before general clinical use can be recommended.
Aluminum Oxide↗
Influence of prolonged thermal cycling and water storage on the tensile bond strength of composite to NiCr alloy.
OBJECTIVES: The purpose of this study was to evaluate the bond strength and bond durability of new adhesive systems (both micromechanical and chemo-mechanical) to a beryllium-free nickel-chromium alloy (NiCr). METHODS: Plexiglass tubes filled with composite were bonded to NiCr alloy discs. Groups of 24 samples were bonded using six different bonding systems. Subgroups of eight bonded samples were stored in an isotonic artificial saliva solution (37 degrees C) either for 1 d, 30 d or 150 d. In addition, the 30 and 150 d samples were thermal cycled for 7,500 or 37,500 cycles, respectively. RESULTS: The bond strength of a conventional BisGMA composite to sandblasted NiCr was statistically significantly lower than that of chemo-mechanical bonding systems and decreased continuously during the storage time of 150 d. The additional use of a silane on the sandblasted alloy resulted only in a slight, statistically insignificant increase in bond strength. Statistically significantly higher and more durable bonds to NiCr alloy were achieved either with the combination of silica coating and use of a conventional BisGMA composite or with the combination of sandblasting and the use of a composite modified with a phosphate monomer. In these systems, the bond strengths were limited by the cohesive strength of the resin composites. However, a newly developed composite containing the same active phosphate monomer showed a statistically significant decrease in bond strength (cohesive strength) over storage time. SIGNIFICANCE: Longer-term storage times in a wet environment are needed in laboratory tests to examine the durability of bonding systems.
Bisphenol A-Glycidyl Methacrylate↗
Effects of sandblasting and silica-coating procedures on pure titanium.
Silica coating titanium improves chemomechanical bonding. Sandblasting is recommended as a pretreatment to thermal silica coating (Silicoater MD) or as part of a tribochemical silica coating process (Rocatec). This study evaluated the effects of sandblasting and coating techniques on volume loss, surface morphology and composition changes in pure titanium. Volume loss of titanium was similar to values reported for base alloys and does not seem to be critical for the clinical fit of restorations. Embedded alumina particles were found in the titanium after sandblasting and the alumina content increased to a range of 27.5-39.3 wt% as measured by EDS. Following tribochemical silica coating, a layer of small silica particles remained on the surface, increasing the silica content to a range of 17.9-19.5 wt%. Ultrasonic cleaning removed loose alumina or silica particles from the surface, resulting in only slight decreases in alumina or silica contents, suggesting firm attachment of most of the alumina and silica to the titanium surface. Silica content following thermal silica coating treatment increased only slightly from the sandblasted specimen to 1.4 wt%. The silica layer employed by these silica coating methods differs widely in both morphology and thickness. These results provide a basis for explanation of adhesive failure modes in bond strength tests and for developing methods to optimize resin bonding. Clinically, ultrasonic cleaning of sandblasted and tribochemically silica coated titanium should improve resin bonding as loose surface particles are removed without relevant changes in composition.
Aluminum Oxide↗
Glucose transporter (GLUT 4) content and insulin receptor kinase activity in muscles of the LA/N-cp rat.
In this study we compared insulin binding activity, insulin receptor tyrosine kinase activity, and GLUT 4 protein content in six muscles from LA/N-cp rats and their lean controls. LA/N-cp rats had an approximate 20-fold increase in insulin concentration (837 +/- 113 vs 40 +/- 1), associated with significant (p < 0.01) decreases in both insulin binding activity per mg muscle and in muscle GLUT 4 content. Maximum insulin tyrosine kinase activity was also lower in muscle from LA/N-cp rats, but no difference was noted when tyrosine kinase activity was expressed per receptor. These data indicate that there are at least two defects in the insulin action cascade in muscle from LA/N-cp rats that contribute to the insulin resistance in these animals.
Animals↗
Analysis of radiocontrast-induced nephropathy by dual-labeled radionuclide clearance.
RATIONALE AND OBJECTIVES: This study was devised to develop a method of measuring the acute effects of radiocontrast media on renal function and assessing the relationship of the dose of radiocontrast media infused with the incidence of radiocontrast-induced renal failure. In addition, the drug adenosine phosphate-magnesium chloride (ATP-MgCl2) was evaluated as a renoprotective agent. METHODS: Eighteen patients with pre-existing renal impairment, (serum creatinine greater than 133 mumol/L) were randomized to receive a continuous infusion of ATP-MgCl2 or placebo before and during a radiocontrast procedure. Subjects were monitored with daily serum creatinine and with radionuclide renal clearance studies at baseline, during, and 24 hours after the radiocontrast procedure. RESULTS: There was an initial deterioration in renal clearance in the entire study group (from 44.2 +/- 4.6 to 32.6 +/- 3.9 mL/min, P = .001) which was independent of the dose of radiocontrast infused. There was a persistent deterioration in renal clearance only in those who received greater than 135 mL of contrast media (from 48.6 +/- 7.8 to 37.1 +/- 3.9 mL/min, P = .05). There also was an increase in serum creatinine that persisted only in those subjects who received greater than 135 mL of contrast media (230 +/- 27 to 283 +/- 44 mumol/L, P = .01). CONCLUSION: Persistent deterioration in renal function after radiocontrast administration appears to be dose-dependent and is not prevented by the use of ATP-MgCl2. Radionuclide techniques are useful in monitoring acute changes in renal function during radiocontrast procedures and may be of value in assessing renal impairment in future intervention studies.
Acute Kidney Injury↗
Increased Nitrogenase-Dependent H(2) Photoproduction by hup Mutants of Rhodospirillum rubrum.
Transposon Tn5 mutagenesis was used to isolate mutants of Rhodospirillum rubrum which lack uptake hydrogenase (Hup) activity. Three Tn5 insertions mapped at different positions within the same 13-kb EcoRI fragment (fragment E1). Hybridization experiments revealed homology to the structural hydrogenase genes hupSLM from Rhodobacter capsulatus and hupSL from Bradyrhizobium japonicum in a 3.8-kb EcoRI-ClaI subfragment of fragment E1. It is suggested that this region contains at least some of the structural genes encoding the nickel-dependent uptake hydrogenase of R. rubrum. At a distance of about 4.5 kb from the fragment homologous to hupSLM, a region with homology to a DNA fragment carrying hypDE and hoxXA from B. japonicum was identified. Stable insertion and deletion mutations were generated in vitro and introduced into R. rubrum by homogenotization. In comparison with the wild type, the resulting hup mutants showed increased nitrogenase-dependent H(2) photoproduction. However, a mutation in a structural hup gene did not result in maximum H(2) production rates, indicating that the capacity to recycle H(2) was not completely lost. Highest H(2) production rates were obtained with a mutant carrying an insertion in a nonstructural hup-specific sequence and with a deletion mutant affected in both structural and nonstructural hup genes. Thus, besides the known Hup activity, a second, previously unknown Hup activity seems to be involved in H(2) recycling. A single regulatory or accessory gene might be responsible for both enzymes. In contrast to the nickel-dependent uptake hydrogenase, the second Hup activity seems to be resistant to the metal chelator EDTA.
Journal Article↗
Relation between the resolution of HLA-typing and the chance of finding an unrelated bone marrow donor.
The chance of finding an unrelated bone marrow donor depends on the size of the donor registry, the frequency of the patient's HLA phenotype and the degree of histoincompatibility considered acceptable. We have studied 60 unrelated bone marrow donor searches and the probability of finding a donor when increasing HLA-compatibility requirements were applied. For 21 (35%) of the patients no donor could be identified who was (serologically) matched for all six ABDR antigens. For the remaining 39 (65%), a median of two (range 1-20) blood samples from serologically-matched potential donors was obtained for further analysis. Eighteen (30%) patients appeared to be mismatched with all the pre-selected donors because of DR (sub-)type mismatches detected by oligotyping. A further 7 (12%) patients did not have an MLC and/or cytotoxic T lymphocyte precursor (CTLp) negative donor. Thus, a 'perfectly matched' donor was found for 11 (18%) patients. To find a suitable donor for more patients we propose that many or all the potential donors identified in the various registries for a particular patient are simultaneously evaluated as many of the serologically ABDR-matched donors will appear to be incompatible after high resolution HLA-typing. This strategy will not only allow selection of the best matched donor more rapidly but the consequent use of high resolution typing might also lead to the definition of a certain number of acceptable mismatches.
Bone Marrow Transplantation↗
Primary radiation therapy for endometrial carcinoma: a case controlled study.
PURPOSE: Primary radiation therapy is generally considered inferior to a surgical approach for patients with endometrial carcinoma and is reserved for patients with a high operative risk. These patients are usually elderly, have multiple medical problems and frequently die of intercurrent disease. To evaluate the efficacy of primary radiation therapy a case controlled analysis comparing corrected survival of patients treated with primary radiation to patients treated with surgical therapy with or without radiation therapy was performed. METHODS AND MATERIALS: Sixty-four patients treated with primary radiation therapy were retrospectively studied. A Kaplan-Meier product limit survival analysis was used to estimate survival among patients treated with primary radiation therapy. A case control study matched by clinical stage, tumor grade, and time of diagnosis was performed. The Mantel-Cox statistic was used to evaluated the equality of the survival curves. RESULTS: Primary radiation therapy was used to treat 9.0% of the patients with endometrial carcinoma during the study period. Cardiovascular disease, diabetes, age greater than 80 and morbid obesity were the most common indications. Ninety percent of patients had either Stage I or II disease. Forty-eight of the 64 patients (75%) completed treatment which included both teletherapy and brachytherapy. Ten patients received brachytherapy only. Twelve complications, both acute and chronic, occurred in eleven patients (17%). Intercurrent disease accounted for 13 of the 36 (36%) of the deaths. Clinical stage of disease and histologic grade of the tumor were significant predictors of survival, p = 0.0001 and p = 0.013, respectively. The case controlled study of Stage I and II patients treated by primary radiation therapy matched to surgically treated controls showed no statistical difference in survival. Dilatation and curettage after the completion of radiation therapy was predictive of local control, p = 0.003. CONCLUSION: Although surgery followed by tailored radiation therapy has become widely accepted therapy for Stage I and II endometrial carcinoma, even in patients who are a poor operative risk, the survival with primary radiation therapy is not statistically different.
Adult↗
Increased muscle glucose uptake in response to chronic glyburide treatment is not related to changes in glucose transporter (GLUT4) protein.
1. The mechanism of action of glyburide (a sulfonylurea) on muscle has been investigated by measuring glucose uptake and glucose transporter (GLUT4) protein levels after chronic glyburide treatment. 2. A dietary induced insulin resistant rat model (4 wk of high-fat, high-sucrose feeding) was given glyburide (2 mg/kg/day) for 10 days and glucose uptake was measured in a perfused hindquarter preparation. 3. Protein levels of the GLUT4 glucose transporter were determined by Western analysis. 4. After 7 days of treatment, rats fed glyburide had lower blood glucose concentrations 2 hr (72 +/- 5 vs 103 +/- 12 mg/dl) and 24 hr (97 +/- 7 vs 123 +/- 7 mg/dl) after glyburide administration with no difference in serum insulin levels compared to vehicle treated animals. 5. Glucose uptake was approx doubled in basal state (0 insulin) in response to glyburide (2.8 +/- 0.4 vs 1.7 +/- 0.2 mumol/g per hr). 6. Maximal insulin (100 nM) stimulated glucose uptake tended to be higher in the glyburide treated group, but did not reach statistical significance (8.0 +/- 0.7 vs 7.0 +/- 0.6 mumol/g per hr). 7. Western analysis revealed no significant effect of glyburide on the GLUT4 protein level in skeletal muscle. 8. These results suggest that glyburide alters glucose uptake through some mechanism other than alterations in the level of the GLUT4 glucose transporter protein.
Animals↗
Three-dimensional investigation of the accuracy of impression materials after disinfection.
The influence of the two new disinfection systems Hygojet/MD 520 and Impresept on the accuracy of eight impression materials was evaluated with a clinically relevant abutment arrangement. In addition, an "aseptic" irreversible hydrocolloid was tested under the same test conditions but without the disinfection procedure. The dimensional changes of all eight impression materials related to the disinfection procedures were small. Although statistically significant interactions of the impression materials and the disinfection systems were found, the influence of the two tested disinfection systems on the dimensional accuracy of the impressions does not seem to be clinically relevant. From the standpoint of impression accuracy, both tested disinfection systems and the tested "aseptic" irreversible hydrocolloid can be recommended for clinical and laboratory use.
Analysis of Variance↗
Sandblasting and silica-coating of dental alloys: volume loss, morphology and changes in the surface composition.
Silica-coating alloys improves chemo-mechanical bonding. Sandblasting is recommended as pretreatment to thermal silica-coating or as part of a tribochemical silica-coating process. This study evaluated the effects of sandblasting and coating techniques on volume loss, surface morphology and compositional changes in noble (AuAgCu) and base alloys (NiCr and CoCr). Volume loss was statistically significantly higher in the noble as compared to the base alloys but does not seem to be critical for the clinical fit of restorations. Embedded alumina particles were found in all alloys after sandblasting and the alumina content increased to a range of 14 to 37 wt% as measured by EDS. Following tribochemical silica-coating, a layer of small silica particles remained on the surface, increasing the silica content to between 12 and 20 wt%. Ultrasonic cleaning removed loose alumina or silica particles from the surface, resulting in only slight decreases in alumina or silica contents, thus suggesting firm attachment of the major part of alumina and silica to the alloy surface. Clinically, ultrasonic cleaning of sandblasted and tribochemically silica-coated alloys might improve resin bonding as loose surface particles are removed without relevant changes in composition. Silica content following thermal silica-coating treatment increased only slightly from the sandblasted specimen. The silica layer employed by these silica-coating methods differs widely in both morphology and thickness. These results provide a basis for explanation of adhesive failure modes in bond strength tests which will possibly optimize resin bonding. Further research is needed to characterize the outermost surface layers after these treatments and the exact location of adhesive failures.
Analysis of Variance↗
In vitro comparison of conventional crowns and a new all-ceramic system.
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Aluminum Oxide↗
Fracture strength of all-porcelain, resin-bonded bridges after testing in an artificial oral environment.
Twenty all-porcelain In-Ceram bridges were resin bonded to natural teeth on a study model. Ten of the test specimens were fixed on abutments placed directly in resin, and 10 were supported by an artificial periodontal membrane. Incisal forces of physiological magnitude and direction were applied in three bridges of both groups (test samples) in an artificial oral environment (1250,000 cycles). The fracture strength of the six test and 14 control specimens was tested in a universal testing instrument and the rupture strength measured. There was no significant difference between the fracture strength of the test and control samples. The artificial periodontal membrane around the abutment teeth did not reduce the fracture strength of the In-Ceram bridges.
Aluminum Oxide↗
[Penile venous outflow occlusion: a comparison of erectile function and cavernosometry before and after percutaneous interventions].
After percutaneous transpenile or retrograde venous occlusion for the treatment of a cavernous leak, the clinical results were correlated with cavernosometric flow measurements in 27 patients. In 15 patients, venous occlusion led to a reduction of the maintenance flow: in patients who showed improvement there was an average reduction of 30 ml/min, in those without improvement or deterioration it averaged 0.3 or 13 ml/min respectively. In 7 patients there was increased flow (up to +21 ml/min). One of these patients showed improved erectile function; the remaining 6 showed no change as was also the case in 5 other patients who had no change in cavernosometric measurements. Our findings suggest a multifactorial cause of the venous leaks.
Embolization, Therapeutic↗
Effect of aging and bolus variables on pharyngeal and upper esophageal sphincter motor function.
Effect of aging, bolus volume, temperature, and consistency on the pharyngeal peristalsis, as well as the effect of aging on the upper esophageal sphincter (UES) resting pressure and its response to esophageal distension by air and balloon, were studied in 14 young and 12 healthy elderly volunteers. In both age groups there was no significant volume or temperature effect on amplitude, duration, or velocity of the pharyngeal peristalsis. Compared with water swallows, mashed potato swallows resulted in a significant increase in the amplitude and duration of the hypopharyngeal peristaltic pressure wave (P < 0.05). For water swallows, the amplitude and duration of the peristaltic pressure wave in the hypopharynx were significantly increased in the elderly compared with the young group (P < 0.01). UES resting pressure in the elderly measured 43 +/- 5 (SE) mmHg and was significantly less than that of the young (71 +/- 8 mmHg; P < 0.01). Magnitude of the UES pressure decrease because of esophageal distension by air, as well as magnitude of its pressure increase because of esophageal balloon distension, was similar among young and elderly. 1) Contrary to common expectations, the parameters of the pharyngeal peristaltic pressure wave do not deteriorate in the elderly in their seventh and eighth decade. 2) Compared with the young, hypopharyngeal pressure wave amplitude and duration are significantly increased in the elderly. This increase could be caused by an adaptation response to a pharyngeal outflow compromise. 3) Pharyngeal peristaltic pressure wave amplitude and duration, but not its velocity, are modulated by the bolus consistency. This modulatory mechanism is preserved in the elderly. 4) Although UES resting pressure is significantly decreased in the elderly, its pressure response to esophageal distension by air and balloon is preserved.
Adult↗
[Ultrasound dissection in laparoscopic cholecystectomy].
An ultrasound dissector especially developed for laparoscopic surgery was used during laparoscopic cholecystectomy on 34 patients. The ultrasound power, the volume of suction and irrigation could be determined individually at the generator and activated during the operation with a foot pedal. With the dissector it was possible to fragmentate, emulgate and aspirate simultaneously fat tissue as well as infected edematous structures. The cystic artery and cystic duct, small vessels, lymphatic and connective tissue were not damaged. Therefore this system seems to be excellent for the preparation of Calot's trigonum and blunt dissection of the gallbladder out of its bed, particularly in fatty, acute or chronic infected tissue. No complications were observed within the peri- and postoperative period.
Adult↗