Robot-assisted implantation of a microelectrode array in the occipital lobe as a visual prosthesis: technical note

The prospect of direct interaction between the brain and computers has been investigated in recent decades, revealing several potential applications. One of these is sight restoration in profoundly blind people, which is based on the ability to elicit visual perceptions while directly stimulating the occipital cortex. Technological innovation has led to the development of microelectrodes implantable on the brain surface. The feasibility of implanting a microelectrode on the visual cortex has already been shown in animals, with promising results. Current research has focused on the implantation of microelectrodes into the occipital brain of blind volunteers. The technique raises several technical challenges. In this technical note, the authors suggest a safe and effective approach for robot-assisted implantation of microelectrodes in the occipital lobe for sight restoration.

High-fidelity initialization and control of electron and nuclear spins in a four-qubit register

Single electron spins bound to multi-phosphorus nuclear spin registers in silicon have demonstrated fast (0.8 ns) two-qubit [Formula: see text] gates and long spin relaxation times (~30 s). In these spin registers, when the donors are ionized, the nuclear spins remain weakly coupled to their environment, allowing exceptionally long coherence times. When the electron is present, the hyperfine interaction allows coupling of the spin and charge degrees of freedom for fast qubit operation and control. Here we demonstrate the use of the hyperfine interaction to enact electric dipole spin resonance to realize high-fidelity ([Formula: see text]%) initialization of all the nuclear spins within a four-qubit nuclear spin register. By controllably initializing the nuclear spins to [Formula: see text], we achieve single-electron qubit gate fidelities of F = 99.78 ± 0.07% (Clifford gate fidelities of 99.58 ± 0.14%), above the fault-tolerant threshold for the surface code with a coherence time of [Formula: see text].

Twenty-Three Months Repetitive Transcranial Magnetic Stimulation of the Primary Motor Cortex for Refractory Trigeminal Neuralgia: A Single-Case Study

Treatment refractory or recurrent trigeminal neuralgia (TN) is a severe chronic pain illness. Single-session repetitive transcranial magnetic stimulation (rTMS) has been shown to elicit analgesic effects in several craniofacial pain syndromes, including TN. However, the safety and long-term effect of multi-session rTMS for TN have yet to be fully explored. In this study, we present a case of a patient with medical treatment-refractory TN after microvascular decompression. The patient volunteered to undergo 73 sessions of 10 Hz rTMS over 23 months. Neurovagination was used for precise localization and stimulation of the hand and face representation at the left motor cortex. The numeric pain intensity scores derived using the visual analog scale served as a daily index of treatment efficacy. The patient experienced a significant weekly reduction in pain scores, cumulating in 70.89% overall pain relief. The medication dosages were reduced and then discontinued toward the end of the intervention period. No severe adverse events were reported. From our results, we can conclude that the longitudinal multi-session application of rTMS over the hand and face area of M1 is a safe and effective method for producing long-lasting pain relief in TN. Using rTMS may thus prove helpful as an adjunct to conventional methods for treating pain in TN.

Comparing the Impact of Multi-Session Left Dorsolateral Prefrontal and Primary Motor Cortex Neuronavigated Repetitive Transcranial Magnetic Stimulation (nrTMS) on Chronic Pain Patients

Repetitive transcranial stimulation (rTMS) has been shown to produce an analgesic effect and therefore has a potential for treating chronic refractory pain. However, previous studies used various stimulation parameters (including cortical targets), and the best stimulation protocol is not yet identified. The present study investigated the effects of multi-session 20 Hz (2000 pulses) and 5 Hz (1800 pulses) rTMS stimulation of left motor cortex (M1-group) and left dorsolateral prefrontal cortex (DLPFC-group), respectively. The M1-group (n = 9) and DLPFC-group (n = 7) completed 13 sessions of neuronavigated stimulation, while a Sham-group (n = 8) completed seven sessions of placebo stimulation. The outcome was measured using the German Pain Questionnaire (GPQ), Depression, Anxiety and Stress Scale (DASS), and SF-12 questionnaire. Pain perception significantly decreased in the DLPFC-group (38.17%) compared to the M1-group (56.11%) (p ≤ 0.001) on the later sessions. Health-related quality of life also improved in the DLPFC-group (40.47) compared to the Sham-group (35.06) (p = 0.016), and mental composite summary (p = 0.001) in the DLPFC-group (49.12) compared to M1-group (39.46). Stimulation of the left DLPFC resulted in pain relief, while M1 stimulation was not effective. Nonetheless, further studies are needed to identify optimal cortical target sites and stimulation parameters.

Clinical outcomes of tooth-supported leucite-reinforced glass-ceramic crowns after a follow-up time of 13-15 years

OBJECTIVES

The aim of this retrospective clinical study was to investigate the survival rate, technical and biologic complications of leucite-reinforced glass-ceramic crowns after a follow-up time of 13-15 years.

MATERIAL AND METHODS

Fifty-three patients with 131 crowns were invited to the follow-up visit. The reconstructions were re-examined clinically and radiographically using the modified USPHS criteria and periodontal parameters of probing pocket depth (PPD), plaque index (PI), sulcus bleeding index (SBI). Patient satisfaction and post-operative sensitivity of the abutment teeth were evaluated with a questionnaire. The overall survival rate and the Kaplan-Meier survival estimate were calculated both on crown and patient level. Technical and biological complications were reported descriptively on crown level. The p-value <0.05 was considered statistically significant.

RESULTS

Thirty-eight patients (12 men, 26 women) with 93 crowns were examined. The overall survival rate of all the crowns was 79.6% after a mean observation period of 14.4 ± 1.2 years. Most of the failures occurred after 11.1 years. The most common clinical failures were inacceptable ceramic fractures or chippings, which occurred in 5 out of 93 crowns (5.4%) and periodontitis, seen in 4 out of 93 teeth (4.3%). The most frequent technical complications were related to occlusal wear. Biological complications were not common.

CONCLUSIONS

Leucite-reinforced glass-ceramic crowns showed a high survival rate of 79.6% after an observation period of 13-15 years. Ceramic fractures and periodontitis accounted for the majority of clinical failures.

CLINICAL SIGNIFICANCE

Leucite-reinforced glass-ceramic crowns can be considered a safe and predictable treatment choice for restoring both anterior and posterior teeth.

Preservation of nasal turbinates in endoscopic, anterior skull base surgery-yes, we can!

Objective

To evaluate the frequency, type and indications of nasal turbinate (NT) resection during endoscopic, anterior skull base surgery and to analyze factors that may have an impact on the need of NT removal.

Methods

In this retrospective cohort study, 306 subjects (150 males and 156 females, mean age 55.4 ± 15.3 years) who underwent multidisciplinary, transnasal, endoscopic tumor surgery of the anterior skull base using 4-handed techniques between 2011 and 2019 at the Department of Otorhinolaryngology, Medical University of Graz, were included.

Results

In the majority of interventions (n = 281/306; 91.8%), all NT were preserved. Significant factors influencing the need of NT resections turned out to be type of endoscopic approach (p < 0.001; V = 0.304), sagittal (p = 0.003; d = 0.481) and transversal (p = 0.017; d = 0.533) tumor diameter, tumor type (p < 0.001; V = 0.355) and tumor location (p < 0.001; V = 0.324).

Conclusions

NT can be preserved in the majority of patients undergoing tumor resection in anterior, transnasal, skullbase surgery and routine resection of NT should be avoided. Variables that have an impact on the need of NT resections are types of endoscopic approaches, sagittal and transversal tumor extension and tumor type. These factors should be considered in planning of surgery and preoperative information of patients.

Long-term outcomes of all-ceramic inlays and onlays after a mean observation time of 11 years

OBJECTIVES

Long-term retrospective evaluation of the survival rate and the technical and biologic outcomes of all-ceramic inlays and onlays in premolars and molars.

METHOD AND MATERIALS

Fifty-four patients treated as part of a prospective clinical trial and having received 157 inlays and 27 onlays made out of a leucite-reinforced glass-ceramic (IPS Empress) in premolars and molars, were invited to the present follow-up examination. The survival of the restorations was evaluated. The biologic outcomes were assessed by measuring the pocket probing depth (PPD), the Plaque Index (PI), and the Sulcus Bleeding Index (SBI). The technical behavior was evaluated using modified US Public Health Service criteria (modUSPHS). Finally, patient satisfaction was recorded with a questionnaire. Data of patients and restored teeth were analyzed descriptively, and continuous variables were given in mean values and standard deviations. For the analysis of the restoration survival over time, the Kaplan-Meier survival estimate was calculated. The level of statistical significance was set at P < .05.

RESULTS

Thirty-six patients (20 women, 16 men; mean age 50.9 years) with 132 restorations, 107 inlays and 25 onlays, were examined after a mean observation time of 11.2 ± 4.3 years. The overall 11-year survival rate of the 132 restorations was 80.3%. Inlays exhibited an 11-year survival rate of 80.4% and onlays of 80.0%. Twenty-two technical complications occurred. Ceramic fractures (10.6%) and chipping (2.3%) were the most frequent complications. Six biologic complications occurred (4.5%).

CONCLUSION

Glass-ceramic inlays and onlays presented favorable long-term clinical survival and success rates. Technical complications were predominant, and biologic problems remained rare. More clinical long-term data are needed.

Calculation of the Hadronic Vacuum Polarization Contribution to the Muon Anomalous Magnetic Moment

We present a first-principles lattice QCD+QED calculation at physical pion mass of the leading-order hadronic vacuum polarization contribution to the muon anomalous magnetic moment. The total contribution of up, down, strange, and charm quarks including QED and strong isospin breaking effects is a_{μ}^{HVP LO}=715.4(18.7)×10^{-10}. By supplementing lattice data for very short and long distances with R-ratio data, we significantly improve the precision to a_{μ}^{HVP LO}=692.5(2.7)×10^{-10}. This is the currently most precise determination of a_{μ}^{HVP LO}.

Calculation of the Hadronic Vacuum Polarization Disconnected Contribution to the Muon Anomalous Magnetic Moment

We report the first lattice QCD calculation of the hadronic vacuum polarization (HVP) disconnected contribution to the muon anomalous magnetic moment at physical pion mass. The calculation uses a refined noise-reduction technique that enables the control of statistical uncertainties at the desired level with modest computational effort. Measurements were performed on the 48^{3}×96 physical-pion-mass lattice generated by the RBC and UKQCD Collaborations. We find the leading-order hadronic vacuum polarization a_{μ}^{HVP(LO)disc}=-9.6(3.3)(2.3)×10^{-10}, where the first error is statistical and the second systematic.

The blood-tendon barrier: identification and characterisation of a novel tissue barrier in tendon blood vessels

Tissue barriers function as "gate keepers" between different compartments (usually blood and tissue) and are formed by specialised membrane-associated proteins, localising to the apicolateral plasma membrane domain of epithelial and endothelial cells. By sealing the paracellular space, the free diffusion of solutes and molecules across epithelia and endothelia is impeded. Thereby, tissue barriers contribute to the establishment and maintenance of a distinct internal and external environment, which is crucial during organ development and allows maintenance of an organ-specific homeostatic milieu. So far, various epithelial and endothelial tissue barriers have been described, including the blood-brain barrier, the blood-retina barrier, the blood-testis barrier, the blood-placenta barrier, and the cerebrospinal fluid (CSF)-brain barrier, which are vital for physiological function and any disturbance of these barriers can result in severe organ damage or even death. Here, we describe the identification of a novel barrier, located in the vascular bed of tendons, which we term the blood-tendon barrier (BTB). By using immunohistochemistry, transmission electron microscopy, and tracer studies we demonstrate the presence of a functional endothelial barrier within tendons restricting the passage of large blood-borne molecules into the surrounding tendon tissue. We further provide in vitro evidence that the BTB potentially contributes to the creation of a distinct internal tissue environment impacting upon the proliferation and differentiation of tendon-resident cells, effects which might be fundamental for the onset of tendon pathologies.

Standard Model Prediction for Direct CP Violation in K→ππ Decay

We report the first lattice QCD calculation of the complex kaon decay amplitude A_{0} with physical kinematics, using a 32³×64 lattice volume and a single lattice spacing a, with 1/a=1.3784(68) GeV. We find Re(A_{0})=4.66(1.00)(1.26)×10(-7) GeV and Im(A_{0})=-1.90(1.23)(1.08)×10(-11) GeV, where the first error is statistical and the second systematic. The first value is in approximate agreement with the experimental result: Re(A_{0})=3.3201(18)×10(-7) GeV, while the second can be used to compute the direct CP-violating ratio Re(ϵ^{'}/ϵ)=1.38(5.15)(4.59)×10^{-4}, which is 2.1σ below the experimental value 16.6(2.3)×10(-4). The real part of A_{0} is CP conserving and serves as a test of our method while the result for Re(ϵ^{'}/ϵ) provides a new test of the standard model theory of CP violation, one which can be made more accurate with increasing computer capability.

Emerging understanding of the ΔI=1/2 rule from lattice QCD

There has been much speculation as to the origin of the ΔI=1/2 rule (ReA0/ReA2≃22.5). We find that the two dominant contributions to the ΔI=3/2, K→ππ correlation functions have opposite signs, leading to a significant cancelation. This partial cancelation occurs in our computation of ReA2 with physical quark masses and kinematics (where we reproduce the experimental value of A2) and also for heavier pions at threshold. For ReA0, although we do not have results at physical kinematics, we do have results for pions at zero momentum with mπ≃420  MeV [ReA0/ReA2=9.1(2.1)] and mπ≃330  MeV [ReA0/ReA2=12.0(1.7)]. The contributions which partially cancel in ReA2 are also the largest ones in ReA0, but now they have the same sign and so enhance this amplitude. The emerging explanation of the ΔI=1/2 rule is a combination of the perturbative running to scales of O(2  GeV), a relative suppression of ReA2 through the cancelation of the two dominant contributions, and the corresponding enhancement of ReA0. QCD and electroweak penguin operators make only very small contributions at such scales.

Tendons from non-diabetic humans and rats harbor a population of insulin-producing, pancreatic beta cell-like cells

Diabetes mellitus is a risk factor for various types of tendon disorders. The mechanisms underlying diabetes associated tendinopathies remain unclear, but typically, systemic factors related to high blood glucose levels are thought to be causally involved. We hypothesize that tendon immanent cells might be directly involved in diabetic tendinopathy. We therefore analyzed human and rat tendons by immunohistochemistry, laser capture microdissection, and single cell PCR for pancreatic β-cell associated markers. Moreover, we examined the short term effects of a single injection of streptozotocin, a toxin for GLUT2 expressing cells, in rats on insulin expression of tendon cells, and on the biomechanical properties of Achilles tendons. Tendon cells, both in the perivascular area and in the dense collagenous tissue express insulin and Glut2 on both protein and mRNA levels. In addition, glucagon and PDX-1 are present in tendon cells. Intraperitoneal injection of streptozotocin caused a loss of insulin and insulin mRNA in rat Achilles tendons after only 5 days, accompanied by a 40% reduction of mechanical strength. In summary, a so far unrecognized, extrapancreatic, insulin-producing cell type, possibly playing a major role in the pathophysiology of diabetic tendinopathy is described. In view of these data, novel strategies in tendon repair may be considered. The potential of the described cells as a tool for treating diabetes needs to be addressed by further studies.

K→(ππ)(I=2) decay amplitude from lattice QCD

We report on the first realistic ab initio calculation of a hadronic weak decay, that of the amplitude A(2) for a kaon to decay into two π mesons with isospin 2. We find ReA(2)=(1.436±0.063(stat)±0.258(syst))10(-8) GeV in good agreement with the experimental result and for the hitherto unknown imaginary part we find ImA(2)=-(6.83±0.51(stat)±1.30(syst))10(-13) GeV. Moreover combining our result for ImA(2) with experimental values of ReA(2), ReA(0), and ε'/ε, we obtain the following value for the unknown ratio ImA(0)/ReA(0) within the standard model: ImA(0)/ReA(0)=-1.63(19)(stat)(20(syst)×10(-4). One consequence of these results is that the contribution from ImA(2) to the direct CP violation parameter ε' (the so-called Electroweak Penguin contribution) is Re(ε'/ε)(EWP)=-(6.52±0.49(stat)±1.24(syst))×10(-4). We explain why this calculation of A(2) represents a major milestone for lattice QCD and discuss the exciting prospects for a full quantitative understanding of CP violation in kaon decays.

Perivascular cells of the supraspinatus tendon express both tendon- and stem cell-related markers

Tendons and ligaments are often affected by mechanical injuries or chronic impairment but other than muscle or bone they possess a low healing capacity. So far, little is known about regeneration of tendons and the role of tendon precursor cells in that process. We hypothesize that perivascular cells of tendon capillaries are progenitors for functional tendon cells and are characterized by expression of marker genes and proteins typical for mesenchymal stem cells and functional tendon cells. Immunohistochemical characterization of biopsies derived from intact human supraspinatus tendons was performed. From these biopsies perivascular cells were isolated, cultured, and characterized using RT-PCR and Western blotting. We have shown for the first time that perivascular cells within tendon tissue express both tendon- and stem/precursor cell-like characteristics. These findings were confirmed by results from in vitro studies focusing on cultured perivascular cells isolated from human supraspinatus tendon biopsies. The results suggest that the perivascular niche may be considered a source for tendon precursor cells. This study provides further information about the molecular nature and localization of tendon precursor cells, which is the basis for developing novel strategies towards tendon healing and facilitated regeneration.

The anaphase-promoting complex/cyclosome (APC/C) is required for rereplication control in endoreplication cycles

Endoreplicating cells undergo multiple rounds of DNA replication leading to polyploidy or polyteny. Oscillation of Cyclin E (CycE)-dependent kinase activity is the main driving force in Drosophila endocycles. High levels of CycE-Cdk2 activity trigger S phase, while down-regulation of CycE-Cdk2 activity is crucial to allow licensing of replication origins. In mitotic cells relicensing in S phase is prevented by Geminin. Here we show that Geminin protein oscillates in endoreplicating salivary glands of Drosophila. Geminin levels are high in S phase, but drop once DNA replication has been completed. DNA licensing is coupled to mitosis through the action of the anaphase-promoting complex/cyclosome (APC/C). We demonstrate that, even though endoreplicating cells never enter mitosis, APC/C activity is required in endoreplicating cells to mediate Geminin oscillation. Down-regulation of APC/C activity results in stabilization of Geminin protein and blocks endocycle progression. Geminin is only abundant in cells with high CycE-Cdk2 activity, suggesting that APC/C-Fzr activity is periodically inhibited by CycE-Cdk2, to prevent relicensing in S-phase cells.

Platelets contribute to enhanced MCP-1 levels in patients with chronic heart failure

BACKGROUND

Increasing scientific data suggest a role for inflammation in chronic heart failure (CHF), but up to now the exact mechanisms are still not clear. Recently, platelets were identified as inducing inflammation partly by releasing cytokines. This new aspect necessitates further studies about the contribution of platelets for the inflammatory setting of CHF.

METHODS

50 CHF patients (mean 66.9 (SD 12.6) years, mean EF 22.1% (SD 9.1)) and 25 healthy controls (mean 63.6 (SD 10.2) years) were examined. MCP-1 serum levels were measured via EIA, expression of platelet CD154 by flow cytometry. In in-vitro experiments activated platelets were cocultured with human umbilical vein endothelial cells (HUVEC) in the presence and absence of anti-CD154 antibodies. MCP-1 in the supernatants was measured by EIA.

RESULTS

CHF patients showed significantly enhanced MCP-1 levels (median: 191.8; 25th centile: 153.7; 75th centile: 227.1 pg/ml vs median: 101.0; 25th centile: 86.7; 75th centile: 117.5 pg/ml, p<0.001). MCP-1 levels positively correlated with severity of CHF. In the cell coculture model activated platelets were able to significantly induce MCP-1 release from HUVEC in a CD154-dependent manner. Furthermore, CHF patients showed enhanced platelet CD154 expression with a positive correlation with MCP-1 levels. Aspirin therapy had no influence on either CD154 expression or MCP-1 levels.

CONCLUSIONS

Platelets can contribute to enhanced MCP-1 levels in CHF. MCP-1 is markedly elevated in serum of CHF patients showing a direct correlation with the severity of symptoms and the degree of left ventricular dysfunction. Further studies are required to test whether MCP-1 blocking or sophisticated anti-platelet strategies may represent new therapeutic options in CHF.

Overexpression of the human neonatal Fc-receptor alpha-chain in trophoblast-derived BeWo cells increases cellular retention of beta2-microglobulin

Major histocompatibility complex (MHC) class I and MHC class I-type molecules such as the neonatal Fcgamma-receptor, FcRn, are heterodimers consisting of a transmembrane alpha-chain non-covalently associated with beta2-microglobulin (beta2m). Human placental villous syncytiotrophoblast (STB) lacks MHC class I molecules, but express hFcRn that mediates materno-fetal transmission of immunoglobulin G (IgG). Trophoblast-derived BeWo cells that are used to study placental IgG transport likewise express beta2m and low levels of hFcRn alpha-chain. The contribution of FcRn alpha-chain in retention and subcellular distribution of beta2m in STB and BeWo cells is unclear. To investigate this issue, we increased expression of hFcRn alpha-chain in BeWo cells (BeWo/hFcRn) by cDNA transfection. Overexpressed hFcRn protein exhibited the characteristic pH-dependent IgG binding and association with beta2m. In comparison to parental BeWo cells, beta2m mRNA levels in BeWo/hFcRn cells were not significantly altered, but total cell-associated beta2m protein was increased by 120%. Treatment of BeWo and BeWo/hFcRn cells with brefeldin A, an inhibitor of the secretory pathway, abrogated this effect, demonstrating that hFcRn alpha-chain expression retained otherwise secreted beta2m. Flow cytometry revealed that beta2m plasma membrane expression was unaffected by alpha-chain overexpression whereas by fluorescence microscopy a preferential staining of beta2m in peripheral endosomes was observed.

Completion of mitosis requires neither fzr/rap nor fzr2, a male germline-specific Drosophila Cdh1 homolog

Proteolysis of mitotic regulators like securins and cyclins requires Fizzy(FZY)/Cdc20 and Fizzy-related(FZR)/Hct1/Cdh1 proteins. Budding yeast Cdh1 acts not only during G1, but is also required for B-type cyclin degradation during exit from mitosis when Cdh1 is a target of the mitotic exit network controlling progression through late mitosis and cytokinesis. In contrast, observations in frog and Drosophila embryos have suggested that the orthologous FZR is not involved during exit from mitosis. However, the potential involvement of minor amounts of maternally derived FZR was not excluded in these studies. Similarly, the reported absence of severe mitotic defects in chicken Cdh1(-/-) cells might be explained by the recent identification of multiple Cdh1 genes [10]. Here, we have carefully analyzed the FZR requirement during exit from mitosis in Drosophila, which, apart from fzr, has only one additional homolog. We find that this fzr2 gene, although expressed in the male germline, is not expressed during mitotic divisions. Moreover, by characterizing fzr alleles, we demonstrate that completion of mitosis including Cyclin B degradation does not require FZR. However, fzr is an essential gene corresponding to the rap locus, and FZR, which accumulates predominantly in the cytoplasm, is clearly required during G1.

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.

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).

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.

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.

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.

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.

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.

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.

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.

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.

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.