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C Lehner

Publications and source records attributed to C Lehner.

13 recordsLinked to original sources
PubMed2001

Age-related decrease in paired-pulse intracortical inhibition in the human primary motor cortex.

Using biphasic magnetic stimuli, paired-pulse transcranial magnetic stimulation (TMS) at short interstimulus intervals (ISIs) was employed to investigate age-related changes in the balance between intracortical inhibition and facilitation. In 26 right-handed healthy individuals, motor evoked potentials were recorded from the relaxed right first dorsal interosseus muscle after paired-pulse TMS of the left primary motor hand area. The magnitude of intracortical paired-pulse inhibition at ISIs of 1-5 ms was markedly reduced in elderly individuals, whereas no age effect was observed for intracortical paired-pulse facilitation at ISIs of 11-15 ms. This finding demonstrates that normal aging is associated with a relative decrease in the excitability of intracortical inhibitory circuits. In conclusion, paired-pulse TMS provides a non-invasive means of studying age-related functional changes in the motor cortex.

Adult↗
PubMed2000

Subthreshold 5-Hz repetitive transcranial magnetic stimulation of the human primary motor cortex reduces intracortical paired-pulse inhibition.

Paired-pulse transcranial magnetic stimulation (TMS) at short interstimulus intervals was employed to investigate short-term effects of 5-Hz repetitive TMS (rTMS) over the primary motor hand area (M1(HAND)) on intracortical excitability. In ten healthy individuals, 1250 pulses of 5-Hz rTMS were applied at 90% of motor resting threshold over the left M1(HAND). Ten minutes after 5-Hz rTMS, paired-pulse inhibition was significantly reduced, whereas paired-pulse facilitation was not modified. Sham-rTMS had no lasting effect on intracortical excitability. These findings suggest that subthreshold 5-Hz rTMS causes a short-term modulation of the excitability of intracortical circuitry in the stimulated M1(HAND). The lasting effect of subthreshold 5-Hz rTMS on intracortical inhibition provides a useful probe for studying short-term plasticity of the human M1(HAND).

Adult↗
PubMed2000

Repetitive transcranial magnetic stimulation causes a short-term increase in the duration of the cortical silent period in patients with Parkinson's disease.

In ten patients with Parkinson's disease (PD) and ten age-matched healthy controls, we applied 15 30-s trains of subthreshold 5-Hz repetitive transcranial magnetic stimulation (rTMS) over the primary motor hand area. Ten minutes after rTMS, PD patients showed a significant prolongation of the transcranially evoked silent period (SP) in the contralateral first dorsal interosseus muscle, whereas the SP remained unchanged in healthy subjects. Since the duration of the transcranially evoked SP is a well-established measure of intracortical inhibition, this finding demonstrates that rTMS is capable of inducing a short-term increase in intracortical inhibition in PD. The lack of a prolongation of the SP in healthy controls suggests that PD patients may be particularly susceptible to modulatory effects of rTMS on motocortical inhibition.

Adult↗
PubMed2000

Soft tissue correction of a single-tooth pontic space: a comparative quantitative volume assessment.

STATEMENT OF PROBLEM: Various augmentation procedures are recommended for the correction of localized alveolar ridge defects. However, no study has quantitatively evaluated the results of these procedures to date. PURPOSE: This study compared 2 soft tissue augmentation surgeries commonly used to alter contours of single-tooth pontic space by quantifying 3-dimensional volume changes with the optical projection Moiré method at 1 and 3.5 months after surgery. MATERIAL AND METHODS: Twenty-four patients required surgery. Each patient had a localized alveolar ridge defect, corresponding to a mesial-distal width of 1 single tooth. The defect of 12 patients was corrected with a subepithelial connective tissue graft; the remaining 12 patients were treated by receiving a free full-thickness gingival graft, which included epithelium and connective tissue with fatty tissue. Six unoperated defects of 6 patients formed the control group. For each defect, an impression was made before treatment, at 1 and 3.5 months after surgery to measure the volume changes on the dental casts with a validated projection Moiré system. Volume change was assessed relative to the preoperative dimension at the buccal and crestal aspects of the single-tooth pontic space. RESULTS: At 3.5 months postsurgery, mean volumetric gain for the connective tissue group with 159 mm(3) (SD +/- 80) was significantly greater (P =.027) than for free full-thickness gingival graft group with 104 mm(3) (SD +/- 31). CONCLUSION: The applied projection Moiré method proved its applicability in assessing 3-dimensional volume changes of pontic spaces with a single-tooth width. Volumetric assessment after 1 and 3.5 months revealed significantly greater volume gain with the subepithelial connective tissue graft in comparison to the free full-thickness gingival graft.

Adipose Tissue↗
PubMed2000

Long-term survival estimates of cast gold inlays and onlays with their analysis of failures.

The aim of the present study was to assess the clinical behaviour of cast gold restorations with respect to define a gold control against current and future ceramic and composite restorations. The study sample included 50 patients with 303 cast gold restorations. All restorations were cemented with a non-adhesive technique. A total of 303 restorations were evaluated clinically and radiographically using modified United States Public Health Service criteria. Restorations recorded as having an A- or a B-rating were defined as successful. Of the 303 restorations, 42 were judged as failures, which resulted in a failure rate of 13.8% for a mean observation time (+/- s.d.) of 18.7 ( +/- 9.5) years. The estimated Kaplan-Meier survival rates (s.e.) were 96.1% (+/- 1.1%) at 10 years, 87.0% (+/- 2.2%) at 20 years and 73.5% (+/- 5.4%) at 30 years. In total, biological reasons were counted 25 times in comparison to 17 technical reasons for those 42 failed cast gold restorations, with 17 secondary caries (40%) as the most common biological reason and with 13 retention losses (31%) as the most common technical reason. The endodontically treated tooth was exclusively identified as a risk factor. The restoration type (inlay versus onlay) did not influence the survival rate.

Confidence Intervals↗
PubMed1998

Fizzy is required for activation of the APC/cyclosome in Xenopus egg extracts.

The Xenopus homologue of Drosophila Fizzy and budding yeast CDC20 has been characterized. The encoded protein (X-FZY) is a component of a high molecular weight complex distinct from the APC/cyclosome. Antibodies directed against FZY were produced and shown to prevent calmodulin-dependent protein kinase II (CaMKII) from inducing the metaphase to anaphase transition of spindles assembled in vitro in Xenopus egg extracts, and this was associated with suppression of the degradation of mitotic cyclins. The same antibodies suppressed M phase-promoting factor (MPF)-dependent activation of the APC/cyclosome in interphase egg extracts, although they did not appear to alter the pattern or extent of MPF-dependent phosphorylation of APC/cyclosome subunits. As these phosphorylations are thought to be essential for APC/cyclosome activation in eggs and early embryos, we conclude that at least two events are required for MPF to activate the APC/cyclosome, allowing both chromatid segregation and full degradation of mitotic cyclins. The first one, which does not require FZY function, is the phosphorylation of APC/cyclosome subunits. The second one, that requires FZY function (even in the absence of MAD2 protein and when the spindle assembly checkpoint is not activated) is not yet understood at its molecular level.

Amino Acid Sequence↗
PubMed1998

A screen for lethal mutations in the chromosomal region 59AB suggests that bellwether encodes the alpha subunit of the mitochondrial ATP synthase in Drosophila melanogaster.

We report the isolation and complementation mapping of lethal mutations within the 59AB region on the second chromosome of Drosophila melanogaster. The newly induced lethal mutations in this region define four different complementation groups. Using existing and newly induced deficiencies, these loci can be assigned to three different chromosomal intervals. Moreover, complementation analysis with chromosomes carrying various P element insertions, in combination with a molecular characterization of the corresponding insertion sites, suggests that the previously described male sterile mutation bellwether is an allele of an essential gene that encodes the alpha subunit of the mitochondrial ATP synthase.

Alleles↗
PubMed1997

Short-term results of IPS-Empress full-porcelain crowns.

PURPOSE: A leucite-reinforced, glass-ceramic material was recently introduced for clinical use. In this clinical trial, IPS-Empress material was tested in the form of full-porcelain crowns. MATERIALS AND METHODS: Thirty-four patients were restored with 78 full-porcelain crowns. After etching the crowns with hydrofluoric acid, they were silanized and luted using dentin bonding agents and resin composite cement, which was primarily a dual-cured type. The 41 anterior and 37 posterior crowns were evaluated clinically with a mirror and probe, radiographically, and using clinical photographs, according to the modified United States Public Health Service criteria. Restorations having neither charlie nor delta criteria were defined as successful, and their survival rate was calculated according to Kaplan-Meier analysis. RESULTS: The mean observation period for the 78 restorations was 19.7 +/- 8.5 months. Seventy-four crowns were defined as successful. Four restorations failed because of fractures. Three of the four failures occurred in the first 2 months after cementation. The survival rate was estimated to be 95% successful after 2 years in service. Eighty percent of the crowns demonstrated an excellent esthetic result. CONCLUSIONS: The initial clinical results of this esthetic full-porcelain crown system are encouraging. However, because of fatigue phenomena for all ceramic materials, a longer observation period is needed to provide a definitive prognosis about the long-term clinical behavior.

Aluminum Silicates↗
PubMed1996

Short-term results of IPS-Empress inlays and onlays.

PURPOSE: A leucite-reinforced, glass-ceramic material was recently introduced for clinical use. In this clinical trial, IPS-Empress inlays and onlays were evaluated using the modified United States Public Health Service (USPHS) criteria. MATERIALS AND METHODS: The teeth of 36 patients were restored with 105 posterior inlays and 25 onlays, fabricated by an indirect technique. After etching the restorations with hydrofluoric acid, they were silanized and luted using composite cements. The restorations were evaluated visually, clinically with a mirror and probe, and by bitewing radiographs and clinical photographs, using modified USPHS criteria. Restorations having neither charlie nor delta criteria were defined as successful, and their survival rate was calculated according to Kaplan-Meier analysis. RESULTS: The mean observation period for the 130 restorations was 23.4 +/- 6.1 months. After 2 years, 127 restorations were successful with an estimated survival rate of 97.5%. Three restorations failed because of fractures. The esthetic results were excellent. CONCLUSIONS: The initial clinical results of this esthetic restorative material are encouraging. However, because of fatigue phenomena for all ceramic materials, a longer observation period is needed to provide a definitive prognosis of the long-term clinical behavior.

Aluminum Silicates↗
PubMed1984

A new 185,000-dalton skeletal muscle protein detected by monoclonal antibodies.

The M line, which transverses the center of the thick filament region of skeletal muscle sarcomeres, appears to be a complex array of multiple structural elements. To date, two proteins have definitely been shown to be associated with the M line. They are MM-CK, localized in the M 4,4' substriations, and a 165,000-dalton (164 kd) protein, referred to as both M-protein and myomesin. Here we report the positive identification of a third M-line protein of 185 kd. In the course of making monoclonal antibodies (mAbs) against a 165-kd fraction, we also obtained mAbs that bound to the M line of isolated myofibrils as detected by indirect immunofluorescence, but recognized a protein band of 185 kd in immunoblotting experiments with either the original immunogen or low ionic strength myofibril extracts as antigenic targets. The evidence that the 185- and 165-kd proteins are distinct protein species is based on the separation of the two proteins into discrete peaks by ion exchange chromatography, the distinctive patterns of their degradation products, and non-cross-reactivity of any of seven mAbs. These mAbs recognize three unique antigenic determinants on the 185-kd molecule and at least two and probably four sites on the 165-kd molecule as determined from competitive binding and immunofluorescence experiments. To resolve the problem of multiple nomenclature for the 165-kd protein, the 185-kd protein will be referred to as myomesin and the 165-kd protein as M-protein.

Animals↗
PubMed1982

Protein-protein interactions of cytochrome oxidase in inner mitochondrial membranes. The effect of liposome fusion on protein rotational mobility.

Rotational diffusion of cytochrome oxidase in the inner membrane of rat liver mitochondria was measured by detecting the decay of absorption anisotropy after photolysis of the heme a3.CO complex by a vertically polarized laser flash. As in previous experiments with beef heart mitochondria (Kawato, S., Sigel, E., Carafoli, E., and Cherry, R. J. (1980) J. Biol. Chem. 255, 5508-5510), co-existence of rotating cytochrome oxidase (mean rotational relaxation time, phi, of 700 to 1400 microseconds) and immobilized cytochrome oxidase (phi greater than 20 ms) was observed in mitochondria and mitoplasts. The effect of lipid/protein ratio by weight (L/P) on the relative proportions of mobile and immobile cytochrome oxidase was investigated following the fusion of soybean phospholipid vesicles with mitoplasts. The fusion procedure yielded four separate fractions upon sucrose density gradient centrifugation with L/P as follows: 0.3 in Pellet, 0.7 in Band 3, 1.5 in Band 2, and 3.0 in Band 1. The percentage of rotationally mobile cytochrome oxidase (phi = 700 to 1000 microseconds) in each of the different bands was found to be 16% in Pellet, 25% in Band 3, 47% in Band 2, and 76% in Band 1 at 37 degrees C. The dependence of the amount of mobile cytochrome oxidase on L/P indicates that the fraction of aggregated protein progressively decreases with decreasing concentration of proteins in the membrane. Thus, the large immobile fraction of cytochrome oxidase in mitochondrial inner membranes can be explained by nonspecific protein aggregation which is a consequence of the low L/P. The decrease in the mobile fraction in Pellet compared with mitoplasts was shown to be due to the pH 6.5 incubation used for fusion.

Animals↗