Assessing the specificity of the relationship between brain alpha oscillations and tonic pain.

Recent research proposed that the slowing of individual alpha frequency (IAF) could be an objective marker of pain. However, it is unclear whether this research can fully address the requirements of specificity and sensitivity of IAF to the pain experience. Here, we sought to develop a robust methodology for assessing the specificity of the relationship between alpha oscillations and acute tonic pain in healthy individuals. We recorded electroencephalography (EEG) of 36 volunteers during consecutive 5-minute sessions of painful hot water immersion, innocuous warm water immersion and aversive, non-painful auditory stimulus, matched by unpleasantness to the painful condition. Participants rated stimulus unpleasantness throughout each condition. We isolated two regions of the scalp displaying peak alpha activity across participants: centro-parietal (CP) and parieto-occipital (PO) ROI. In line with previous research our findings revealed decreased IAF during hot compared with warm stimulation, however the effect was not specific for pain as we found no difference between hot and sound in the CP ROI (compared to baseline). In contrast, the PO ROI reported the same pattern of differences, but their direction was opposite to the CP in that this ROI revealed faster frequency during hot condition than controls. Finally, we show that IAF in both ROIs did not mediate the relationship between the experimental manipulation and the affective experience. Altogether, these findings emphasize the importance of a robust methodological and analytical design to disclose the functional role of alpha oscillations during affective processing. Likewise, they suggest the absence of a causal role of IAF in the generation of acute pain experience in healthy individuals.

The temporal sensitivity to the tactile-induced double flash illusion mediates the impact of beta oscillations on schizotypal personality traits.

The coherent experience of the self and the world depends on the ability to integrate vs. segregate sensory information. Optimal temporal integration between the senses is mediated by oscillatory properties of neural activity. Previous research showed reduced temporal sensitivity to multisensory events in schizotypy, a personality trait linked to schizophrenia. Here we used the tactile-induced Double-Flash-Illusion (tDFI) to investigate the tactile-to-visual temporal sensitivity in schizotypy, as indexed by the temporal window of illusion (TWI) and its neural underpinnings. We measured EEG oscillations within the beta band, recently shown to correlate with the tDFI. We found individuals with higher schizotypal traits to have wider TWI and slower beta waves accounting for the temporal window within which they perceive the illusion. Our results indicate reduced tactile-to-visual temporal sensitivity to mediate the effect of slowed oscillatory beta activity on schizotypal personality traits. We conclude that slowed oscillatory patterns might constitute an early marker for psychosis proneness.

Oscillatory Properties of Functional Connections Between Sensory Areas Mediate Cross-Modal Illusory Perception.

The presentation of simple auditory stimuli can significantly impact visual processing and even induce visual illusions, such as the auditory-induced double flash illusion (DFI). These cross-modal processes have been shown to be driven by occipital oscillatory activity within the alpha band. Whether this phenomenon is network specific or can be generalized to other sensory interactions remains unknown. The aim of the current study was to test whether cross-modal interactions between somatosensory-to-visual areas leading to the same (but tactile-induced) DFI share similar properties with the auditory DFI. We hypothesized that if the effects are mediated by the oscillatory properties of early visual areas per se, then the two versions of the illusion should be subtended by the same neurophysiological mechanism (i.e., the speed of the alpha frequency). Alternatively, if the oscillatory activity in visual areas predicting this phenomenon is dependent on the specific neural network involved, then it should reflect network-specific oscillatory properties. In line with the latter, results recorded in humans (both sexes) show a network-specific oscillatory profile linking the auditory DFI to occipital alpha oscillations, replicating previous findings, and tactile DFI to occipital beta oscillations, a rhythm typical of somatosensory processes. These frequency-specific effects are observed for visual (but not auditory or somatosensory) areas and account for auditory-visual connectivity in the alpha band and somatosensory-visual connectivity in the beta band. We conclude that task-dependent visual oscillations reflect network-specific oscillatory properties favoring optimal directional neural communication timing for sensory binding.SIGNIFICANCE STATEMENT We investigated the oscillatory correlates of the auditory- and tactile-induced double flash illusion (DFI), a phenomenon where two interleaved beeps (taps) set within 100 ms apart and paired with one visual flash induce the sensation of a second illusory flash. Results confirm previous evidence that the speed of individual occipital alpha oscillations predict the temporal window of the auditory-induced illusion. Importantly, they provide novel evidence that the tactile-induced DFI is instead mediated by the speed of individual occipital beta oscillations. These task-dependent occipital oscillations are shown to be mediated by the oscillatory properties of the neural network engaged in the task to favor optimal temporal integration between the senses.

Higher proneness to multisensory illusions is driven by reduced temporal sensitivity in people with high schizotypal traits.

A coherent sense of self, typically altered in schizophrenia, is accompanied by a coherent ability to integrate sensory information. According to the idea of a psychosis continuum, high schizotypal traits in the general population may be associated to higher proneness to multisensory illusions, akin to schizophrenia. We directly tested this hypothesis by means of the double-flash illusion in participants with low and high schizotypal scores. We confirmed the higher proneness to illusions in the high-schizotypal group. Crucially, such higher proneness was fully explained by a significantly reduced temporal sensitivity to integrate sensory information. We conclude that reduced temporal sensitivity accounts for enhanced proneness to illusions in people at higher risk and represents an early marker of psychosis.

Use of the natural tooth for soft tissue development: a case series.

The achievement of optimal esthetics around anterior dental implants has been a major challenge for many clinicians. The key to an esthetically pleasing appearance lies in the clinician's ability to properly manage the soft tissue profile around dental implants. Hence, the purpose of this case report is to describe a new technique that uses the patient's own natural tooth for the provisional implant restoration to develop soft tissue architecture that is almost identical to the patient's original immediately after tooth extraction. Ten consecutively treated patients were included in this series. Clinical measurements included soft tissue height, papilla appearance, and probing pocket depths. Other parameters such as radiographic bone levels and quality-of-life ratings were also recorded. Results from this study showed that all patients achieved a normal or Class 1 papilla appearance similar to the original appearance of the natural tooth. All patients were very happy with the treatment outcome. This newly suggested approach for restoring an anterior implant can be valuable and esthetically pleasing.

Effect of rhPDGF-BB delivery on mediators of periodontal wound repair.

Growth factors such as platelet-derived growth factor (PDGF) exert potent effects on wound healing including the regeneration of tooth-supporting structures. This investigation examined the effect of the local delivery of PDGF-BB when combined with reconstructive periodontal surgery on local wound fluid (WF) levels of PDGF-AB, vascular endothelial growth factor (VEGF), and bone collagen telopeptide (ICTP) in humans with advanced periodontitis. Sixteen patients exhibiting localized periodontal osseous defects were randomized to one of three groups (beta-TCP carrier alone, beta-TCP + 0.3 mg/mL of recombinant human PDGF-BB [rhPDGF-BB], or beta-TCP + 1.0 mg/mL of rhPDGF-BB) and monitored for 6 months. WF was harvested and analyzed for PDGF-AB, VEGF, and ICTP WF levels. Teeth contralateral to the target lesions served as controls. Increased levels of VEGF in the WF was observed for all surgical treatment groups with the 1.0 mg/mL rhPDGF-BB group showing the most pronounced difference at 3 weeks in the AUC analysis versus control (p < 0.0001). PDGF-AB WF levels were increased for the carrier alone group compared to both rhPDGFBB groups. Low-dose rhPDGF-BB application elicited increases in ICTP at days 3-5 in the wound healing process, suggesting a promotion of bone turnover at early stages of the repair process (p < 0.02). These results demonstrate contrasting inducible expression patterns of PDGF-AB, VEGF, and ICTP during periodontal wound healing in humans.

Live 3D echocardiography: a replacement for traditional 2D echocardiography?

OBJECTIVE: We describe the development of real-time 3D imaging and review the previously used versions of 3D echocardiography so that the reader will appreciate why current developments truly do represent a quantum leap in the technology. CONCLUSION: Three-dimensional echocardiography has now been shown to have several advantages over 2D echocardiography, particularly for volume measurements, visualization of septal defects, and whole-valve evaluation. Given these data, it is clear that 3D echocardiography is here to stay and soon will become part of routine echocardiographic examinations.

Canine impactions: incidence and management.

Impacted teeth present many problems for the orthodontist. They can compromise tooth movement, esthetics, and functional outcomes. The second most commonly impacted tooth, after the maxillary third molar, is the maxillary canine, with an incidence from 1% to 2.5%. Maxillary canines can be impacted facially or palatally and are more common in female patients than in male patients. Therefore, the purpose of this paper is to address the incidence and etiology associated with impacted maxillary canines, the clinical and radiographic evaluation of the situation, and the techniques for managing this problem. Papers related to this topic were identified and reviewed thoroughly. A decision tree involving the various techniques employed to expose impacted canines is presented, together with methods used to identify the location of impacted canines. The impacted canine can be properly managed with proper diagnosis and technique.

Periodontal regeneration techniques for treatment of periodontal diseases.

The ultimate goal of periodontal therapy is the regeneration of structures lost to disease. Conventional surgical approaches such as open-flap debridement offer only limited regeneration potential.Currently, surgical procedures for predictable regeneration of periodontal tissues are being developed, analyzed, and employed in clinical practice. This article addresses current trends in periodontal regeneration. Various materials/agents such as bone replacement grafts, barrier membranes, and biologic modifiers currently used for the regeneration of periodontal infrabony and furcation defects are discussed.

Discovery of a Selective S1P1 Receptor Agonist Efficacious at Low Oral Dose and Devoid of Effects on Heart Rate.

Gilenya (fingolimod, FTY720) was recently approved by the U.S. FDA for the treatment of patients with remitting relapsing multiple sclerosis (RRMS). It is a potent agonist of four of the five sphingosine 1-phosphate (S1P) G-protein-coupled receptors (S1P1 and S1P3-5). It has been postulated that fingolimod's efficacy is due to S1P1 agonism, while its cardiovascular side effects (transient bradycardia and hypertension) are due to S1P3 agonism. We have discovered a series of selective S1P1 agonists, which includes 3-[6-(5-{3-cyano-4-[(1-methylethyl)oxy]phenyl}-1,2,4-oxadiazol-3-yl)-5-methyl-3,4-dihydro-2(1H)-isoquinolinyl]propanoate, 20, a potent, S1P3-sparing, orally active S1P1 agonist. Compound 20 is as efficacious as fingolimod in a collagen-induced arthritis model and shows excellent pharmacokinetic properties preclinically. Importantly, the selectivity of 20 against S1P3 is responsible for an absence of cardiovascular signal in telemetered rats, even at high dose levels.

Asymmetric synthesis of beta-amino-gamma-substituted-gamma-butyrolactones: double diastereoselective conjugate addition of homochiral lithium amides to homochiral alpha,beta-unsaturated esters.

Chiral alpha,beta-unsaturated esters, containing a single, gamma-stereogenic centre, show modest levels of substrate control upon conjugate addition of lithium dibenzylamide. Double diastereoselective conjugate additions of homochiral lithium N-benzyl-N-(alpha-methylbenzyl)amide to the homochiral alpha,beta-unsaturated esters display "matching" and "mismatching" effects. In each case, however, these additions proceed under the dominant stereocontrol of the lithium amide to give the corresponding beta-amino esters in high de. A remarkable reversal in stereoselectivity is noted by changing the ester functionality to an oxazolidinone. Subsequent O-deprotection and cyclisation of the resultant beta-amino adducts gives access to the corresponding beta-amino-gamma-substituted-gamma-butyrolactones in good yield and high de.

Vertical bone augmentation: where are we now?

As the prevalence of implants has increased, so has the challenge to augment the remaining osseous structure to house those implants. The biggest surgical challenge clinically is to augment lost bone vertically. The purpose of this article is to review currently available techniques for achieving greater vertical dimension before implant placement. A literature search was conducted using MEDLINE to find all articles published between 1970 and 2004 regarding vertical bone augmentation. Following the literature search, all articles were reviewed and summarized in this review article of vertical bone augmentation. The results of the research showed that guided-bone regeneration, monocortical onlay grafting, and distraction osteogenesis have the potential to be applied to augment deficient areas vertically. The expectations of dimensional gain and bone quality are unique to each technique, as well as the potential complications. Distraction osteogenesis has had the greatest potential for vertical gain, while guided-bone regeneration and monocortical onlay grafting achieve similar results. The choice of procedure is to be based upon the patient's existing anatomy, degree of vertical deficiency, and willingness to participate in treatment.

Effect of rhPDGF-BB on bone turnover during periodontal repair.

PURPOSE: Growth factors such as platelet-derived growth factor (PDGF) exert potent effects on wound healing including the regeneration of periodontia. Pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) is a well-known biomarker of bone turnover, and as such is a potential indicator of osseous metabolic activity. The objective of this study was to evaluate the release of the ICTP into the periodontal wound fluid (WF) following periodontal reconstructive surgery using local delivery of highly purified recombinant human PDGF (rhPDGF)-BB. METHODS: Forty-seven human subjects at five treatment centres possessing chronic severe periodontal disease were monitored longitudinally for 24 weeks following PDGF regenerative surgical treatment. Severe periodontal osseous defects were divided into one of three groups and treated at the time of surgery with either: beta-tricalcium phosphate (TCP) osteoconductive scaffold alone (active control), beta-TCP+0.3 mg/ml of rhPDGF-BB, or beta-TCP+1.0 mg/ml of rhPDGF-BB. WF was harvested and analysed for local ICTP levels by radioimmunoassay. Statistical analysis was performed using analysis of variance and an area under the curve analysis (AUC). RESULTS: The 0.3 and 1.0 mg/ml PDGF-BB treatment groups demonstrated increases in the amount of ICTP released locally for up to 6 weeks. There were statistically significant differences at the week 6 time point between beta-TCP carrier alone group versus 0.3 mg/ml PDGF-BB group (p<0.05) and between beta-TCP alone versus the 1.0 mg/ml PDGF-BB-treated lesions (p<0.03). The AUC analysis revealed no statistical differences amongst groups. CONCLUSION: This study corroborates the release of ICTP as a measure of active bone turnover following local delivery of PDGF-BB to periodontal osseous defects. The amount of ICTP released from the WF revealed an early increase for all treatment groups. Data from this study suggests that when PDGF-BB is delivered to promote periodontal tissue engineering of tooth-supporting osseous defects, there is a direct effect on ICTP released from the wound.

Characterizing vortex ring behavior during ventricular filling with Doppler echocardiography: an in vitro study.

Doppler ultrasound color M-mode imaging (CMM) has been proposed as a noninvasive means of quantifying diastolic function by measuring flow propagation into the left ventricle. However, the relationship between CMM-derived parameters and underlying fluid dynamics is still unclear. The purpose of this study was to couple high-resolution velocimetry measurements with ultrasound Doppler and CMM measurements in order to shed light on the relationship between CMM flow propagation and inflow dynamics using a simple yet highly reproducible in vitro model of left ventricular inflow. Two Reynolds number conditions were analyzed: 4000 and 6000. Both conditions produced starting jets that formed vortex rings. Average (N = 5) CMM centerline velocities were in agreement with DPIV centerline velocities, although large uncertainty in CMM data was present (uncertainty +/- 10 cm s(-1)). Two flow propagation parameters were extracted from the CMM data: the first utilized an isovelocity as the marker of flow propagation; the second used local peak velocity as the marker. The isovelocity technique followed the flow proximal to the vortex (wavefront) while the peak velocity method followed peak vorticity, and therefore vortex propagation, closely. We conclude that CMM imaging, while limited in measuring absolute velocities, can be utilized to assess inflow vortex ring properties, and thereby provide useful information on diastolic function.