Attitude Toward Virtual Rehabilitation and Active Video Games Among Therapists in Korea: A Nationwide Survey

In this study, we conducted a survey targeting 191 physical therapists (PTs) and 159 occupational therapists (OTs) in South Korea to explore attitudes toward virtual rehabilitation. Utilizing the Korean version of the ADOPT VR by Glegg et al., OT exhibited significantly more experience with virtual reality (VR) and active video games (AVG) than PT. Therapists with VR/AVG experience scored significantly higher in most categories, and the scores in each category were significantly correlated with the Behavioral Intention category, reflecting the willingness to use VR/AVG. The biggest barriers identified were insufficient funds and setup assistance for the equipment. Differences in responses between the groups with and without VR/AVG experience were most prominent in terms of lack of interest and funding. Therapists' attitudes, perceptions, and intentions toward VR/AVG are crucial factors in the establishment and implementation of VR/AVG; thus, the results of this study provide valuable evidence for future policies related to VR/AVG in rehabilitation medicine.

Effects of Ankle Stabilization Exercises Using Sonic Balance Pad on Proprioception and Balance in Subjects with Ankle Instability

Sound waves generate acoustic resonance energy that penetrates deeply and safely into body areas normal mechanical vibrations cannot reach. The sonic balance pad utilizes these sound waves to create an optimal musculoskeletal response. The purpose of this study was to investigate the effects of a 4-week ankle stabilization exercise program using a sonic balance pad on proprioceptive sense and balance ability in individuals with ankle instability. This study was conducted as a randomized control-group pre-and post-test design in 30 participants (21 females and 9 males) who had experienced an ankle fracture or sprain within the last 5 years or who scored 11 points or more on The Identification of Functional Ankle Instability. The ankle stabilization exercise program was conducted for 4 weeks in the experimental group (n = 15), to which sonic pads were applied, and the control group (n = 15), to which balance pads were applied. All participants were assessed for their intrinsic proprioceptive sense of dorsiflexion and plantarflexion, static balance test, dynamic balance test, and long jump test were measured before and after 4 weeks as dependent variables. After 4 weeks of training, a significant difference was shown in the right dorsiflexion error (Balance pad = PRE: 2.47 ± 0.92; POST: 2.33 ± 1.40, Sonic pad = PRE: 3.27 ± 1.39; POST: 1.20 ± 0.77) and the left plantar flexion error (Balance pad = PRE: 2.00 ± 1.36; POST: 2.73 ± 1.22, Sonic pad = PRE: 3.53 ± 1.25; POST: 2.20 ± 1.01) (p < 0.05) between the experimental and control groups in the proprioception test. In the static balance test, there was no significant difference between the experimental and control groups during the pre, post, and variation stages. However, in the Y-Balance test, which is one of the dynamic balance tests, there was a significant difference between the experimental and control groups at various points, including anterior left (Balance pad = PRE: 72.85 ± 19.95; POST: 63.41 ± 8.66, Sonic pad = PRE: 68.16 ± 6.38; POST: 76.17 ± 3.67), posteromedial right (Balance pad = PRE: 78.59 ± 15.34; POST: 81.41 ± 10.37, Sonic pad = PRE: 86.33 ± 16.44; POST: 102.23 ± 11.53), posteromedial left (Balance pad = PRE: 78.00 ± 16.99; POST: 83.36 ± 10.15, Sonic pad = PRE: 88.96 ± 19.92; POST: 102.45 ± 12.98), posterolateral right (Balance pad = PRE: 78.16 ± 14.33; POST: 82.61 ± 10.73, Sonic pad = PRE: 87.95 ± 17.51; POST: 101.34 ± 15.37), and posterolateral left (Balance pad = PRE: 80.86 ± 14.96; POST: 81.31 ± 7.16, Sonic pad = PRE: 91.23 ± 17.35; POST: 104.18 ± 11.78) (p < 0.05). Moreover, in the single-leg long jump test, which is another dynamic balance test, the experimental group (Sonic pad = PRE: 100.27 ± 29.00; POST: 116.80 ± 28.86) also demonstrated a significant difference in the right single-leg long jump compared to the control group (Balance pad = PRE: 91.87 ± 17.74; POST: 97.67 ± 17.70) (p < 0.05). When a sonic balance pad using sound waves was applied in addition to a 4-week ankle stabilization exercise program for participants with ankle stability, it helped to improve proprioception and dynamic balance ability.

Controlled Electronic and Magnetic Landscape in Self-Assembled Complex Oxide Heterostructures

Complex oxide heterointerfaces contain a rich playground of novel physical properties and functionalities, which give rise to emerging technologies. Among designing and controlling the functional properties of complex oxide film heterostructures, vertically aligned nanostructure (VAN) films using a self-assembling bottom-up deposition method presents great promise in terms of structural flexibility and property tunability. Here, the bottom-up self-assembly is extended to a new approach using a mixture containing a 2Dlayer-by-layer film growth, followed by a 3D VAN film growth. In this work, the two-phase nanocomposite thin films are based on LaAlO3 :LaBO3 , grown on a lattice-mismatched SrTiO3001 (001) single crystal. The 2D-to-3D transient structural assembly is primarily controlled by the composition ratio, leading to the coexistence of multiple interfacial properties, 2D electron gas, and magnetic anisotropy. This approach provides multidimensional film heterostructures which enrich the emergent phenomena for multifunctional applications.

The Effect of Deep and Slow Breathing on Retention and Cognitive Function in the Elderly Population

The purpose of this study was to apply deep and slow breathing to the elderly, who can be classified as potential dementia patients, to confirm changes in the cognitive functions of learning and memory. Forty-five elderly subjects were randomly and evenly divided into a rest group (RG), a before group (BG), and an after group (AG). Measurements of their cognitive abilities were obtained before testing (PT), 30 min after learning (STT), and 24 h after learning (LTT). After PT measurements were obtained from all three groups, the RG and AG conducted new cognitive skills learning, while the BG performed deep and slow breathing (DSB) for 30 min before learning new cognitive skills. After all the three groups underwent 30 min of learning, the STT was performed. Subsequently, the AG performed DSB for 30 min. Finally, 24 h after learning, the LTT was conducted for all three groups. Changes were compared and analyzed by measuring the retention of new cognitive skills and attention, working memory, and spatial perception of cognitive functions. A two-way repeated measure analysis of variance measured the effect of the application of DSB in the three groups. These results demonstrated a significant interaction of time and time*group in all measurements of retention and attention, working memory, and spatial perception. This study confirms the benefit of DSB as part of a dementia prevention training protocol.

Isolation of Streptomycin-Resistant Erwinia pyrifoliae in Korea

As a black shoot blight disease-causing agent, Erwinia pyrifoliae was first reported in 1995 in Korea. A total of 101 isolates of E. pyrifoliae were isolated from samples showing bacterial symptoms collected from apple and pear orchards between 2020 and 2021. These isolates were screened for streptomycin resistance, with one from an orchard in Gwangju showing resistance at 100 μg/ml streptomycin. This streptomycin-resistant E. pyrifoliae (EpSmR) isolate was identified via polymerase chain reaction amplification of the strA/strB gene and an internal region of the ribosomal rpsL gene containing codon 43. EpSmR has a point mutation that altered this codon from lysine (AAA) to threonine (ACA). The strA and strB genes were not identified in EpSmR. EpSmR showed a high resistance to streptomycin (>50,000 μg/ml). This is the first study reporting EpSmR, which emerged due to a mutation in codon 43 of the rpsL gene.

Attitude Toward Telerehabilitation Among Physical and Occupational Therapists in Korea: A Brief Descriptive Report

The attitude toward telerehabilitation (TR) among therapists (191 physical therapists and 159 occupational therapists) in Korea was surveyed. The survey consisted of 15 questions in the following 8 domains: awareness(AW), attitude (AT), perceived usefulness (PU), perceived behavioral control (PBC), self-efficacy (SE), facilitating conditions (FC), barriers (B), and behavioral intention (BI). Therapists with experience in TR responded with higher scores in all domains except B, regardless of their specialty. The most perceived barriers to TR were unmatched insurance fees and a lack of technical support. Experience with TR was a major factor in attitude and behavior intention toward TR.

Atomically engineered interfaces yield extraordinary electrostriction

Electrostriction is a property of dielectric materials whereby an applied electric field induces a mechanical deformation proportional to the square of that field. The magnitude of the effect is usually minuscule (<10^-19 m² V^-2 for simple oxides). However, symmetry-breaking phenomena at the interfaces can offer an efficient strategy for the design of new properties^1,2. Here we report an engineered electrostrictive effect via the epitaxial deposition of alternating layers of Gd₂O₃-doped CeO₂ and Er₂O₃-stabilized δ-Bi₂O₃ with atomically controlled interfaces on NdGaO₃ substrates. The value of the electrostriction coefficient achieved is 2.38 × 10^-14 m² V^-2, exceeding the best known relaxor ferroelectrics by three orders of magnitude. Our theoretical calculations indicate that this greatly enhanced electrostriction arises from coherent strain imparted by interfacial lattice discontinuity. These artificial heterostructures open a new avenue for the design and manipulation of electrostrictive materials and devices for nano/micro actuation and cutting-edge sensors.

Genome-wide analysis in 756,646 individuals provides first genetic evidence that ACE2 expression influences COVID-19 risk and yields genetic risk scores predictive of severe disease

SARS-CoV-2 enters host cells by binding angiotensin-converting enzyme 2 (ACE2). Through a genome-wide association study, we show that a rare variant (MAF = 0.3%, odds ratio 0.60, P=4.5×10^-13) that down-regulates ACE2 expression reduces risk of COVID-19 disease, providing human genetics support for the hypothesis that ACE2 levels influence COVID-19 risk. Further, we show that common genetic variants define a risk score that predicts severe disease among COVID-19 cases.

Effects of deep and slow breathing on stress stimulation caused by high-intensity exercise in healthy adults

The purpose of this study was to investigate the effects of the deep and slow breathing (DSB) on the chain-reaction changes of stress stimulation at over time by measuring electroencephalogram (EEG) and heart rate variability (HRV). Twenty-six healthy subjects were divided into two different groups: control group (CG) and DSB group (DSBG). All subjects were exposed to a stress-stimulated environment with 80% exercise intensity. After the 80% exercise intensity was maintained for 10 minutes, the subjects rested for 5 minutes and then measuring EEG and HRV. The chain-reaction changes of stress stimulation through EEG and HRV analysis showed that DSBG had higher values of alpha/high-beta ratio and High-Frequency (HF) value of HRV than CG (p <.05), and Low-Frequency/High-Frequency (LF/HF) ratio of DSBG is significant time-group interaction, indicating a significant difference between groups (p <.05). In consequence, DSB will be used as a meaningful intervention for patients of stress-related diseases or potential patients.

Walking velocity and modified rivermead mobility index as discriminatory measures for functional ambulation classification of chronic stroke patients

Background

The cut-off values of walking velocity and classification of functional mobility both have a role in clinical settings for assessing the walking function of stroke patients and setting rehabilitation goals and treatment plans.

Objective

The present study investigated whether the cut-off values of the modified Rivermead Mobility Index (mRMI) and walking velocity accurately differentiated the walking ability of stroke patients according to the modified Functional Ambulation Category (mFAC).

Methods

Eighty two chronic stroke patients were included in the study. The comfortable/maximum walking velocities and mRMI were used to measure the mobility outcomes of these patients. To compare the walking velocities and mRMI scores for each mFAC point, one-way analysis of variance and the post-hoc test using Scheffe's method were performed. The patients were categorized according to gait ability into either mFAC = VII or mFAC ≤ VI group. The cut-off values for mRMI and walking velocities were calculated using a receiver-operating characteristic curve. The odds ratios of logistic regression analysis (Wald Forward) were analyzed to examine whether the cut-off values of walking velocity and mRMI can be utilized to differentiate functional walking levels.

Results

Except for mFACs III and IV, maximum walking velocity differed between mFAC IV and mFAC V ( p < 0 . 01 ) , between mFAC V and mFAC VI ( p < 0 . 001 ) , and between mFAC VI and mFAC VII ( p < 0 . 05 ) . The cut-off value of mRMI is > 26 . 5 and the area under the curve is 0.87, respectively; the cut-off value for comfortable walking velocity is > 0 . 77 m/s and the area under the curve is 0.92, respectively; also, the cut-off value for maximum walking velocity is > 0 . 92 m/s and the area under the curve is 0.97, respectively. In the logistic regression analysis, the maximum walking velocity ( > 0 . 92 m/s, OR = 22 . 027 ) and mRMI ( > 26 . 5 scores, OR = 10 . 283 ) are able to distinguish mFAC = VII from mFAC ≤ VI.

Conclusion

The cut-off values of maximum walking velocity and mRMI are recommended as useful outcome measures for assessing ambulation levels in chronic stroke patients during rehabilitation.

Light-Controlled Nanoscopic Writing of Electronic Memories Using the Tip-Enhanced Bulk Photovoltaic Effect

The light control of nonvolatile nanoscale memories could represent a fundamental step toward novel optoelectronic devices with memory and logic functionalities. However, most of the proposed devices exhibit insufficient control in terms of the reversibility, data retention, photosensitivity, limited-photoactive area, and so forth. Here, in a proof-of-concept work, we demonstrate the use of the tip-enhanced bulk photovoltaic (BPV) effect to realize programmable nanoscopic writing of nonphotoactive electronic devices by light control. We show that electronic properties of solid-state memory devices can be reversibly and location-precisely manipulated in the nanoscale using the BPV effect in combination with the nanoscale contact connection, that is, atomic force microscopy (AFM) probe technique in this work. More than 10⁵% reversible switching of tunneling electroresistance of ferroelectric tunnel junctions is exclusively achieved by light control. Using the same light-controlled AFM probe technique, we also present precise nanoscopic and multiple-state writing of LaAlO₃/SrTiO₃ two-dimensional electron gas (2DEG)-based field-effect transistors. The tip-enhanced BPV effect can offer a novel avenue for reversible and multistate light control of a wide range of electronic memory devices in the nanoscale and may lead to more sophisticated functionalities in optoelectronic applications.

Electromagnetic Functionalization of Wide-Bandgap Dielectric Oxides by Boron Interstitial Doping

A surge in interest of oxide-based materials is testimony for their potential utility in a wide array of device applications and offers a fascinating landscape for tuning the functional properties through a variety of physical and chemical parameters. In particular, selective electronic/defect doping has been demonstrated to be vital in tailoring novel functionalities, not existing in the bulk host oxides. Here, an extraordinary interstitial doping effect is demonstrated centered around a light element, boron (B). The host matrix is a novel composite system, made from discrete bulk LaAlO₃ :LaBO₃ compounds. The findings show a spontaneous ordering of the interstitial B cations within the host LaAlO₃ lattices, and subsequent spin-polarized charge injection into the neighboring cations. This leads to a series of remarkable cation-dominated electrical switching and high-temperature ferromagnetism. Hence, the induced interstitial doping serves to transform a nonmagnetic insulating bulk oxide into a ferromagnetic ionic-electronic conductor. This unique interstitial B doping effect upon its control is proposed to be as a general route for extracting/modifying multifunctional properties in bulk oxides utilized in energy and spin-based applications.

Surface passivation of semiconducting oxides by self-assembled nanoparticles

Physiochemical interactions which occur at the surfaces of oxide materials can significantly impair their performance in many device applications. As a result, surface passivation of oxide materials has been attempted via several deposition methods and with a number of different inert materials. Here, we demonstrate a novel approach to passivate the surface of a versatile semiconducting oxide, zinc oxide (ZnO), evoking a self-assembly methodology. This is achieved via thermodynamic phase transformation, to passivate the surface of ZnO thin films with BeO nanoparticles. Our unique approach involves the use of Be_xZn_1-xO (BZO) alloy as a starting material that ultimately yields the required coverage of secondary phase BeO nanoparticles, and prevents thermally-induced lattice dissociation and defect-mediated chemisorption, which are undesirable features observed at the surface of undoped ZnO. This approach to surface passivation will allow the use of semiconducting oxides in a variety of different electronic applications, while maintaining the inherent properties of the materials.

Effects of combined Adeli suit and neurodevelopmental treatment in children with spastic cerebral palsy with gross motor function classification system levels I and II

Background:

Children with cerebral palsy (CP) exhibit diverse gait patterns depending on their neurological deficits and musculoskeletal problems. The Adeli suit treatment (AST) has been proposed as an intensive exercise protocol in the management of CP.

Objectives:

The aim of this study was to compare the effects of a 6-week programme of combined AST and neurodevelopment treatment (NDT) with those of NDT alone on Gross Motor Function Measure (GMFM), balance, and gait in children with CP.

Methods:

Twenty children with CP of Gross Motor Function Classification System levels I and II were randomly assigned to one of the following two groups: (1) NDT or (2) AST/NDT. The participants were assessed using the GMFM, Pediatric Balance Scale (PBS), Timed Up and Go (TUG) test, and spatiotemporal gait parameters.

Results:

The GMFM, PBS, and TUG test for both groups showed a statistically significant increase (p < 0.05). Three children were excluded. Compared to the NDT group (n = 9), the AST/NDT group (n = 8) demonstrated a significant increase in spatiotemporal gait parameters (p < 0.05).

Conclusion:

These results provide evidence for the greater effectiveness of combined AST/NDT than NDT alone in improving spatiotemporal gait parameters but not GMFM, PBS, and TUG test.

Effects of brain-computer interface-based functional electrical stimulation on brain activation in stroke patients: a pilot randomized controlled trial

[Purpose] This study sought to determine the effects of brain-computer interface-based functional electrical stimulation (BCI-FES) on brain activation in patients with stroke. [Subjects] The subjects were randomized to in a BCI-FES group (n=5) and a functional electrical stimulation (FES) group (n=5). [Methods] Patients in the BCI-FES group received ankle dorsiflexion training with FES for 30 minutes per day, 5 times under the brain-computer interface-based program. The FES group received ankle dorsiflexion training with FES for the same amount of time. [Results] The BCI-FES group demonstrated significant differences in the frontopolar regions 1 and 2 attention indexes, and frontopolar 1 activation index. The FES group demonstrated no significant differences. There were significant differences in the frontopolar 1 region activation index between the two groups after the interventions. [Conclusion] The results of this study suggest that BCI-FES training may be more effective in stimulating brain activation than only FES training in patients recovering from stroke.

A reliability of the prototype trunk training system for sitting balance

[Purpose] Cerebral palsy is a disorder that affects balance in the sitting position. Cerebral palsy patients need trunk muscle strengthening and balance training. In order to improve trunk control sensory-motor control training is carried out on an unstable surface. We have developed a Trunk Training System (TTS) that can provide visual feedback using a tilt sensor for balance training in the sitting position. Before using the TTS for training children with cerebral palsy experiments were conducted with healthy adult subjects and the TTS to gather basic data for its improvement. [Subjects] The subjects were 11 healthy men (n=3) and women (n=8). [Methods] Subjects trained at two levels (5°, 10°), in four different directions (anterior, posterior, left, right), three times each. TTS outcome indices (stability index, performance time) were measured. [Results] The stability index and performance time showed high correlation (−0.6<r<1). The measurements of the different task levels and directions showed high reliability (0.9<α). [Conclusion] The TTS may be used to evaluate the range of motion and execution capabilities of sitting balance. Additional experiments will be needed to investigate the validity of the TTS measurements.

Recrystallization of highly-mismatched Be(x)Zn(1-x)O alloys: formation of a degenerate interface

We investigate the effect of thermally induced phase transformations on a metastable oxide alloy film, a multiphase Be(x)Zn(1-x)O (BZO), grown on Al2O3(0001) substrate for annealing temperatures in the range of 600-950 °C. A pronounced structural transition is shown together with strain relaxation and atomic redistribution in the annealed films. Increasing annealing temperature initiates out-diffusion and segregation of Be and subsequent nucleation of nanoparticles at the surface, corresponding to a monotonic decrease in the lattice phonon energies and band gap energy of the films. Infrared reflectance simulations identify a highly conductive ZnO interface layer (thicknesses in the range of ≈ 10-29 nm for annealing temperatures ≥ 800 °C). The highly degenerate interface layers with temperature-independent carrier concentration and mobility significantly influence the electronic and optical properties of the BZO films. A parallel conduction model is employed to determine the carrier concentration and conductivity of the bulk and interface regions. The density-of-states-averaged effective mass of the conduction electrons for the interfaces is calculated to be in the range of 0.31 m0 and 0.67 m0. A conductivity as high as 1.4 × 10(3) S · cm(-1) is attained, corresponding to the carrier concentration n(Int) = 2.16 × 10(20) cm(-3) at the interface layers, and comparable to the highest conductivities achieved in highly doped ZnO. The origin of such a nanoscale degenerate interface layer is attributed to the counter-diffusion of Be and Zn, rendering a high accumulation of Zn interstitials and a giant reduction of charge-compensating defects. These observations provide a broad understanding of the thermodynamics and phase transformations in Be(x)Zn(1-x)O alloys for the application of highly conductive and transparent oxide-based devices and fabrication of their alloy nanostructures.

Validity and reliability of balance assessment software using the Nintendo Wii balance board: usability and validation

Background

A balance test provides important information such as the standard to judge an individual’s functional recovery or make the prediction of falls. The development of a tool for a balance test that is inexpensive and widely available is needed, especially in clinical settings. The Wii Balance Board (WBB) is designed to test balance, but there is little software used in balance tests, and there are few studies on reliability and validity. Thus, we developed a balance assessment software using the Nintendo Wii Balance Board, investigated its reliability and validity, and compared it with a laboratory-grade force platform.

Methods

Twenty healthy adults participated in our study. The participants participated in the test for inter-rater reliability, intra-rater reliability, and concurrent validity. The tests were performed with balance assessment software using the Nintendo Wii balance board and a laboratory-grade force platform. Data such as Center of Pressure (COP) path length and COP velocity were acquired from the assessment systems. The inter-rater reliability, the intra-rater reliability, and concurrent validity were analyzed by an intraclass correlation coefficient (ICC) value and a standard error of measurement (SEM).

Results

The inter-rater reliability (ICC: 0.89-0.79, SEM in path length: 7.14-1.90, SEM in velocity: 0.74-0.07), intra-rater reliability (ICC: 0.92-0.70, SEM in path length: 7.59-2.04, SEM in velocity: 0.80-0.07), and concurrent validity (ICC: 0.87-0.73, SEM in path length: 5.94-0.32, SEM in velocity: 0.62-0.08) were high in terms of COP path length and COP velocity.

Conclusion

The balance assessment software incorporating the Nintendo Wii balance board was used in our study and was found to be a reliable assessment device. In clinical settings, the device can be remarkably inexpensive, portable, and convenient for the balance assessment.

Pinning effect on the band gap modulation of crystalline BexZn1−xO alloy films grown on Al2O3(0001)

Pinning effect on crystalline Be_xZn_1−xO alloy films on Al₂O₃(0001).

Sequential analysis of postural control resource allocation during a dual task test

OBJECTIVE

To investigate the postural control factors influencing the automatic (reflex-controlled) and attentional (high cortical) factors on dual task.

METHODS

We used a dual task model to examine the attentional factors affecting the control of posture, subjecting test subjects to vibration stimulation, one-leg standing and verbal or nonverbal task trials. Twenty-three young, healthy participants were asked to stand on force plates and their centers of pressure were measured during dual task trials. We acquired 15 seconds of data for each volunteer during six dual task trials involving varying task combinations.

RESULTS

We observed significantly different sway patterns between the early and late phases of dual task trials, which probably reflect the attentional demands. Vibration stimulation perturbed sway more during the early than the late phases; with or without vibration stimulation, the addition of secondary tasks decreased sway in all phases, and greater decreases in sway were observed in the late phases, when subjects were assigned nonverbal tasks. Less sway was observed during the nonverbal task in a sequential study.

CONCLUSION

The attentional and automatic factors were analyzed during a sequential study. By controlling the postural control factors, optimal parameters and training methods might be used in clinical applications.

Development of a motor driven rowing machine with automatic functional electrical stimulation controller for individuals with paraplegia; a preliminary study

Objective

To examine the cardiorespiratory responses of patients with spinal cord injury (SCI) paraplegia using a motor driven rowing machine.

Method

Ten SCI patients with paraplegia [A (n=6), B (n=1), and C (n=3) by the American Spinal Injury Association impairment scale] were selected. Two rowing techniques were used. The first used a fixed seat with rowing achieved using only upper extremity movement (fixed rowing). The second used an automatically moving seat, facilitating active upper extremity movement and passive lower extremity movement via the motorized seat (motor rowing). Each patient performed two randomly assigned rowing exercise stress tests 1-3 days apart. The work rate (WR), time, respiratory exchange ratio (R), oxygen consumption (VO₂), heart rate (HR), metabolic equivalents (METs), and rating of perceived exertion (RPE) were recorded.

Results

WR, time, VO₂, and METs were significantly higher after the motor rowing test than after fixed motor rowing test (p<0.05). HR after motor rowing was significantly lower than fixed rowing (p<0.05).

Conclusion

Cardiorespiratory responses as VO₂, HR and METs can be elicited by the motor rowing for people with paraplegic SCI.

Arm motion analysis of stroke patients in activities of daily living tasks: a preliminary study

Analyzing activities of daily living (ADL) for the development of practical upper limb rehabilitation robots is challenging in stroke patients. Basic ADL tasks using an upper limb are defined based on clinical assessment tools. The motions of 8 healthy participants and 8 stroke patients were recorded during defined ADL tasks, and then analyzed with respect to completion time, linearity of motion, and range of motion of the joints. Completion time and motion trajectories were significantly different between stroke subjects and healthy participants. For tasks involving the transfer of an object from a table to the user's mouth, wrist radial-ulnar deviation motions should be taken into account while designing robots for gross movements via elbow and shoulder joints. Our findings can be extended to the design of trajectories of rehabilitation robots as well as of simplified robots.

Loss of the Parkinson's disease-linked gene DJ-1 perturbs mitochondrial dynamics

Growing evidence highlights a role for mitochondrial dysfunction and oxidative stress as underlying contributors to Parkinson's disease (PD) pathogenesis. DJ-1 (PARK7) is a recently identified recessive familial PD gene. Its loss leads to increased susceptibility of neurons to oxidative stress and death. However, its mechanism of action is not fully understood. Presently, we report that DJ-1 deficiency in cell lines, cultured neurons, mouse brain and lymphoblast cells derived from DJ-1 patients display aberrant mitochondrial morphology. We also show that these DJ-1-dependent mitochondrial defects contribute to oxidative stress-induced sensitivity to cell death since reversal of this fragmented mitochondrial phenotype abrogates neuronal cell death. Reactive oxygen species (ROS) appear to play a critical role in the observed defects, as ROS scavengers rescue the phenotype and mitochondria isolated from DJ-1 deficient animals produce more ROS compared with control. Importantly, the aberrant mitochondrial phenotype can be rescued by the expression of Pink1 and Parkin, two PD-linked genes involved in regulating mitochondrial dynamics and quality control. Finally, we show that DJ-1 deficiency leads to altered autophagy in murine and human cells. Our findings define a mechanism by which the DJ-1-dependent mitochondrial defects contribute to the increased sensitivity to oxidative stress-induced cell death that has been previously reported.

WITHDRAWN: Prognostic factors of biochemical recurrence after radical prostatectomy in Korean men with high-risk prostate cancer

This article has been withdrawn consistent with Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). The Publisher apologizes for any inconvenience this may cause.

Cell cycle machinery and stroke

Stroke results from a transient or permanent reduction in blood flow to the brain. The mechanisms involving neuronal death following ischemic insult are complex and not fully understood. One signal which may control ischemic neuronal death is the inappropriate activation of cell cycle regulators including cyclins, cyclin dependent kinases (CDKs) and endogenous cyclin dependent kinase inhibitors (CDKIs). In dividing cells, activation of cell cycle machinery induces cell proliferation. In the context of terminally differentiated-neurons, however, aberrant activation of these elements triggers neuronal death. Indeed, there are several lines of correlative and functional evidence supporting this "cell cycle/neuronal death hypothesis". The objective of this review is to summarize the findings implicating cell cycle machinery in ischemic neuronal death from in vitro and in vivo studies. Importantly, determining and blocking the signaling pathway(s) by which these molecules act to mediate ischemic neuronal death, in conjunction with other targets may provide a viable therapeutic strategy for stroke damage.

Surgical Outcome of Endoscopic Carpal Tunnel Release in 100 Patients with Carpal Tunnel Syndrome

The purpose of this study is to present the surgical outcome of endoscopic carpal tunnel release (ECTR) for the treatment of carpal tunnel syndrome (CTS). One hundred and thirty-one procedures (36 right hands, 33 left hands and 31 bilateral hands) of single portal ECTR were performed upon 100 patients (age range: 36-77 years, mean age: 52.9 years; 98 women and 2 men) with electrodiagnostically proven CTS for 2.5 years from 2001. Preoperative clinical severity and results of electrodiagnostic studies were compared with surgical outcomes at the minimal 3-month postoperative period. Among 131 cases 125 (95.4 %) with complete or significant relief of symptoms were satisfied and 6 (4.6 %) with partial or no relief of symptoms were dissatisfied. There were 2 cases of major complications (one with ulnar nerve injury and the other with ulnar artery injury) that developed in our early experience of ECTR and 1 case of recurrence. The grade of electrodiagnostic abnormalities was associated with surgical outcome but there was no statistical significance between them. The severity of clinical findings, age at onset and symptom duration were not correlated with surgical outcome. In conclusion, ECTR surgery was effective in relieving the symptoms of CTS with a low complication rate after the learning curve period. Thus, ECTR can be an alternative to the traditional open surgery and can be the first procedure for CTS with several advantages over open methods.

C-shaped root canals of mandibular second molars in a Korean population: clinical observation andin vitroanalysis

AIM

To investigate the incidence and morphology of C-shaped root canals of the mandibular second molar in a Korean population.

METHODOLOGY

Through clinical observation, randomly selected 272 mandibular second molars of Korean patients were accessed and evaluated after taking radiographs for determination of working length. In an in vitro analysis, 96 extracted mandibular second molars of Korean patients were collected and embedded in resin using an Endodontic cube technique, and were sectioned at intervals of 1 mm. The specimens were then observed with a surgical microscope and were photographed. Canal configurations were assigned to one of three categories: Category I defined a C-shaped outline without any separation; Category II referred to those with canal configurations, where dentine separated one distinct canal from a buccal or lingual C-shaped canal; Category III had two or more discrete and separate canals.

RESULTS

In clinical observation, 89 of 272 teeth (32.7%) had C-shaped canals. Of the 96 teeth examined in vitro, 30 (31.3%) had C-shaped canals. Upon in vitro analysis, only 1 tooth at the subpulpal level and 10 teeth at the apical 1 mm level were categorized under Category III.

CONCLUSION

There was high prevalence of C-shaped root canals in the mandibular second molars of Koreans. C-shaped canals having semicolon and continuous shapes at the canal orifice have a high possibility of being divided into two or three canals in the apical region.

Attenuation of MPTP-induced neurotoxicity and behavioural impairment in NSE-XIAP transgenic mice

X-linked IAP protein is a potent inhibitor of cell death. Here, we describe a novel transgenic mouse in which the human XIAP gene is expressed under the control of the neuron-specific enolase promoter (NSE-xiap). We demonstrate that nigrostriatal dopamine neurons of NSE-xiap mice were resistant to the damaging effects of the dopaminergic neurotoxin MPTP. MPTP-induced reduction of striatal dopamine metabolism was also attenuated in NSE-xiap mice. Furthermore, NSE-xiap mice treated with MPTP did not exhibit deficits in exploratory behaviour in an open-field test. Taken together, these findings suggest that strategies to enhance neuronal expression of XIAP may provide therapeutic benefit for the treatment of neurodegeneration in Parkinson's disease.

Inhibitors of trypsin-like serine proteases prevent DNA damage-induced neuronal death by acting upstream of the mitochondrial checkpoint and of p53 induction

We have previously shown that the pharmacological agents 4-(2-aminoethyl)=benzenesulfonylfluoride hydrochloride (AEBSF) and Na-p-tosyl-L-lysine chloromethylketone (TLCK), inhibitors of trypsin-like serine proteases, prevent the death of trophic factor-deprived PC12 cells and sympathetic neurons. Both AEBSF and TLCK inhibit caspase activation in this model, but it is unclear whether they do so indirectly or through a direct effect at the level of the caspases. In the current study, we have used these agents in another model of neuronal death that is induced by DNA damage. We find that both agents delay the death of DNA-damaged PC12 cells, neonatal rat sympathetic neurons and embryonic rat cortical neurons. As in the trophic deprivation model, they act upstream of the caspases. In addition, they prevent mitochondrial alterations, such as cytochrome c release or loss of transmembrane potential. In contrast, the general caspase inhibitor bok-asp-fmk does not prevent cytochrome c release and has only a partial and transient effect on loss of transmembrane potential. Interestingly, both AEBSF and TLCK prevent the induction and nuclear accumulation of p53 that is induced by DNA damage in cortical neurons. Therefore, these serine protease inhibitors act at a point upstream in the apoptotic pathway, prior to p53 induction and the mitochondrial checkpoint, to delay neuronal death in this model, and do not act at the level of the caspases. We conclude that therapeutic strategies based on serine protease inhibition may be useful in preventing neuronal cell death.

Caveolae-deficient endothelial cells show defects in the uptake and transport of albumin in vivo

The role of endothelial cell caveolae in the uptake and transport of macromolecules from the blood-space to the tissue-space remains controversial. To address this issue directly, we employed caveolin-1 gene knock-out mice that lack caveolin-1 protein expression and caveolae organelles. Here, we show that endothelial cell caveolae are required for the efficient uptake and transport of a known caveolar ligand, i.e. albumin, in vivo. Caveolin-1-null mice were perfused with 5-nm gold-conjugated albumin, and its uptake was followed by transmission electron microscopy. Our results indicate that gold-conjugated albumin is not endocytosed by Cav-1-deficient lung endothelial cells and remains in the blood vessel lumen; in contrast, gold-conjugated albumin was concentrated and internalized by lung endothelial cell caveolae in wild-type mice, as expected. To quantitate this defect in uptake, we next studied the endocytosis of radioiodinated albumin using aortic ring segments from wild-type and Cav-1-null mice. Interestingly, little or no uptake of radioiodinated albumin was observed in the aortic segments from Cav-1-deficient mice, whereas aortic segments from wild-type mice showed robust uptake that was time- and temperature-dependent and competed by unlabeled albumin. We conclude that endothelial cell caveolae are required for the efficient uptake and transport of albumin from the blood to the interstitium.

Prolactin negatively regulates caveolin-1 gene expression in the mammary gland during lactation, via a Ras-dependent mechanism

Caveolin-1 is a 22-kDa integral membrane protein that has been suggested to function as a negative regulator of mitogen-stimulated proliferation in a variety of cell types, including mammary epithelial cells. Because much of our insight into caveolin-1 function has come from the study of human breast tumor-derived cell lines in culture, the normal physiological regulators of caveolin-1 expression in the mammary gland remain unknown. Here, we examine caveolin-1 expression in mice at different stages of mammary gland development. We show that caveolin-1 expression is significantly down-regulated during late pregnancy and lactation. Upon weaning, mammary gland expression of caveolin-1 rapidly returns to non-pregnant "steady-state" levels. Injection of virgin mice with a battery of hormones normally up-regulated during lactation demonstrates that prolactin is the main mediator of caveolin-1 down-regulation. Virtually identical results were obtained with human mammary epithelial cells (hTERT-HME1) in culture. In addition, we demonstrate that prolactin-mediated down-regulation of caveolin-1 expression occurs at the level of transcriptional control and via a Ras-dependent mechanism. Interestingly, in the mammary gland, both mammary epithelial cells and the surrounding mammary adipocytes show prolactin-mediated down-regulation of caveolin-1. This hormone-dependent regulation of caveolin-1 expression is specific to the mammary fat pad. Finally, we employed HC11 cells, a well-established model of mammary epithelial cell differentiation, to study the possible functional effects of caveolin-1 expression. In the presence of lactogenic hormones, recombinant expression of caveolin-1 in HC11 cells dramatically suppresses the induction of the promoter activity and the synthesis of beta-casein, an established reporter of lactogenic differentiation and milk production. These findings may explain why caveolin-1 levels are normally down-regulated during lactation. This report is the first demonstration that caveolin-1 levels are down-regulated during a normal physiological event in vivo, i.e. lactation, because previous reports have only documented that down-regulation of caveolin-1 occurs during cell transformation and tumorigenesis.

c-Jun mediates axotomy-induced dopamine neuron death in vivo

Expression of the transcription factor c-Jun is induced in neurons of the central nervous system (CNS) in response to injury. Mechanical transection of the nigrostriatal pathway at the medial forebrain bundle (MFB) results in the delayed retrograde degeneration of the dopamine neurons in the substantia nigra pars compacta (SNc) and induces protracted expression and phosphorylation of c-Jun. However, the role of c-Jun after axotomy of CNS neurons is unclear. Here, we show that adenovirus-mediated expression of a dominant negative form of c-Jun (Ad.c-JunDN) inhibited axotomy-induced dopamine neuron death and attenuated phosphorylation of c-Jun in nigral neurons. Ad.c-JunDN also delayed the degeneration of dopaminergic nigral axons in the striatum after MFB axotomy. Taken together, these findings suggest that activation of c-Jun mediates the loss of dopamine neurons after axotomy injury.

Arabidopsis dynamin-like 2 that binds specifically to phosphatidylinositol 4-phosphate assembles into a high-molecular weight complex in vivo and in vitro

Arabadopsis dynamin-like (ADL) 2, a member of the high-molecular weight (M(r)) dynamin family found in Arabidopsis, has been shown to be targeted to the plastid. In the chloroplast, most of the ADL2 was present in the fraction containing the envelope membranes when analyzed by suborganellar fractionation. Sucrose gradient and gel filtration experiments showed that when associated with membranes, ADL2 existed as a high-M(r) complex, whereas the soluble form existed as a monomer. The recombinant ADL2 expressed in Escherichia coli was present as a high-M(r) form and showed higher GTPase activity at a low NaCl concentration, whereas ADL2 existed as a low-M(r) form with a low level of GTPase activity at a high NaCl concentration. Electron microscopy studies revealed that the purified recombinant ADL2 formed spiral-coiled structures or rings. In the presence of guanosine-5'-O-(3-thio)triphosphate, these structures were transformed into a long rod structure. In contrast, in the presence of GDP, these structures disassembled into oligomers that were shown to be tetramer with 4-fold symmetry. Finally, a lipid-binding assay revealed that recombinant ADL2 purified from E. coli bound specifically to phosphatidylinositol 4-phosphate. Together, these results demonstrated that the biochemical properties of ADL2 were very similar to those of dynamin and other related proteins. Based on this similarity, we propose that ADL2 may be involved in vesicle formation at the chloroplast envelope membrane.

APAF1 is a key transcriptional target for p53 in the regulation of neuronal cell death

p53 is a transcriptional activator which has been implicated as a key regulator of neuronal cell death after acute injury. We have shown previously that p53-mediated neuronal cell death involves a Bax-dependent activation of caspase 3; however, the transcriptional targets involved in the regulation of this process have not been identified. In the present study, we demonstrate that p53 directly upregulates Apaf1 transcription as a critical step in the induction of neuronal cell death. Using DNA microarray analysis of total RNA isolated from neurons undergoing p53-induced apoptosis a 5-6-fold upregulation of Apaf1 mRNA was detected. Induction of neuronal cell death by camptothecin, a DNA-damaging agent that functions through a p53-dependent mechanism, resulted in increased Apaf1 mRNA in p53-positive, but not p53-deficient neurons. In both in vitro and in vivo neuronal cell death processes of p53-induced cell death, Apaf1 protein levels were increased. We addressed whether p53 directly regulates Apaf1 transcription via the two p53 consensus binding sites in the Apaf1 promoter. Electrophoretic mobility shift assays demonstrated p53-DNA binding activity at both p53 consensus binding sequences in extracts obtained from neurons undergoing p53-induced cell death, but not in healthy control cultures or when p53 or the p53 binding sites were inactivated by mutation. In transient transfections in a neuronal cell line with p53 and Apaf1 promoter-luciferase constructs, p53 directly activated the Apaf1 promoter via both p53 sites. The importance of Apaf1 as a p53 target gene in neuronal cell death was evaluated by examining p53-induced apoptotic pathways in primary cultures of Apaf1-deficient neurons. Neurons treated with camptothecin were significantly protected in the absence of Apaf1 relative to those derived from wild-type littermates. Together, these results demonstrate that Apaf1 is a key transcriptional target for p53 that plays a pivotal role in the regulation of apoptosis after neuronal injury.

Antinociceptive effects of bee venom acupuncture (apipuncture) in rodent animal models: a comparative study of acupoint versus non-acupoint stimulation

From a clinical perspective, the alternative forms of acupoint stimulation including electroacupuncture, moxibustion and acupressure appear to have more potent analgesic effects than manual needle acupuncture. Bee venom (BV) injection has also been reported to produce persistent nociceptive stimulation and to cause neuronal activation in the spinal cord. In previous study, we observed that BV stimulation into acupoint, namely BV acupuncture or Apipuncture, produced more potent anti-inflammatory and antinociceptive potency in rodent arthritis model as comparing with that of non-acupoint injection. Based on previous report, we decided to further investigate that BV injection into an acupoint produces antinociception as a result of its potent chemical stimulatory effect in both abdominal stretch assay and formalin test. Different doses of BV were injected into an acupoint or a non-acupoint 30 min prior to intraplantar formalin injection or intraperitoneal acetic acid injection. Using the abdominal stretch assay, we found that the high dose of BV (1:100 diluted in 20microl saline) produced a potent antinociceptive effect irrespective of the site of BV injection. In contrast the antinociceptive effect observed in both the writhing and formalin tests following administration of a low dose of BV (1:1000 diluted in 20microl saline) was significantly different between acupoint and non-acupoint sites. BV injection into an acupoint (Zhongwan, Cv. 12) was found to produce significantly greater antinociception than non-acupoint injection (10 mm from Zhongwan, Cv. 12) in the abdominal stretch assay. Similarly, in the formalin test, acupoint (Zusanli, St. 36) injection of BV produced more potent antinociception than non-acupoint injection (gluteal muscle). In contrast, BV injection into an arbitrary non-acupoint site on the back did not produce antinociception in either the writhing or formalin test. These results indicate that BV injection directly into an acupoint can produce a potent antinociceptive effect and suggest that this alternative form of acupoint stimulation (Apipuncture) may be a promising method for the relief of pain.

Caspase 3 deficiency rescues peripheral nervous system defect in retinoblastoma nullizygous mice

The retinoblastoma tumor suppressor protein, pRb, is a key regulator of cell cycle and has been implicated in the terminal differentiation of neuronal cells. Mice nullizygous for pRb die by embryonic day 14.5 from hematopoietic and neurological defects attributed to failed differentiation (Clarke et al., 1992; Jacks et al., 1992; Lee et al., 1992). Previous studies by MacLeod et al. (1996) have demonstrated that the loss of p53 protects Rb-deficient CNS neurons but not peripheral nervous system (PNS) neurons from cell death. Thus, the mechanisms by which PNS neurons undergo apoptosis in response to Rb deficiency remain unknown. In view of the pivotal role of caspase 3 in the regulation of neuronal apoptosis during development, we examined its function in the execution of the wide-spread neuronal cell death induced by Rb deficiency. Our results support a number of conclusions. First, we show that caspase 3 becomes activated in all neuronal populations undergoing apoptosis. Second, caspase 3 deficiency does not extend the life span of Rb null embryos, because double null mutants exhibit high rates of liver apoptosis resulting in erythropoietic failure. Third, Rb/caspase 3 double-mutant neurons of the CNS exhibit widespread apoptosis similar to that seen in Rb mutants alone; thus caspase 3 deficiency does not protect this population from apoptosis. Finally, in contrast to the CNS, neurons of the PNS including those comprising the trigeminal ganglia and the dorsal root ganglia are protected from apoptosis in Rb/caspase 3 double-mutant embryos. Examination of the mechanistic differences between these two cell types suggest that CNS neurons may invoke other caspases to facilitate apoptosis in the absence of caspase 3. These findings suggest that PNS neurons are dependent on caspase 3 for the execution of apoptosis and that caspase 3 may serve as a key therapeutic target for neuroprotection after injury of this cell type.

Phylogenetic diversity of thermophilic actinomycetes and Thermoactinomyces spp. isolated from mushroom composts in Korea based on 16S rRNA gene sequence analysis

Forty one strains isolated from 21 samples of various mushroom composts in Korea were analyzed by 16S rRNA gene sequencing to investigate the phylogenetic diversity of thermophilic actinomycetes. The 25 strains of thermophilic actinomycete isolates were related to the five genera, Pseudonocardia, Saccharomonospora, Saccharopolyspora, Streptomyces, and Thermobifida, within the order Actinomycetales, and 16 strains were classified into the genus Thermoactinomyces within the family Bacillaceae. Most of 41 isolates were encompassed by two genera, Streptomyces and Thermoactinomyces, that were isolated mainly in composts prepared from waste cotton and hay, respectively. Among them, M104 and M109 were placed in distinct taxonomic positions although these strains formed phylogenetic lineages related to the genus Streptomyces and to the family Streptosporangiaceae, respectively. Therefore, a phenetic and genetic characterization of these strains will be needed to pinpoint their taxonomic position.

Cyclin-dependent kinases and P53 pathways are activated independently and mediate Bax activation in neurons after DNA damage

DNA damage has been implicated as one important initiator of cell death in neuropathological conditions such as stroke. Accordingly, it is important to understand the signaling processes that control neuronal death induced by this stimulus. Previous evidence has shown that the death of embryonic cortical neurons treated with the DNA-damaging agent camptothecin is dependent on the tumor suppressor p53 and cyclin-dependent kinase (CDK) activity and that the inhibition of either pathway alone leads to enhanced and prolonged survival. We presently show that p53 and CDKs are activated independently on parallel pathways. An increase in p53 protein levels, nuclear localization, and DNA binding that result from DNA damage are not affected by the inhibition of CDK activity. Conversely, no decrease in retinoblastoma protein (pRb) phosphorylation was observed in p53-deficient neurons that were treated with camptothecin. However, either p53 deficiency or the inhibition of CDK activity alone inhibited Bax translocation, cytochrome c release, and caspase-3-like activation. Taken together, our results indicate that p53 and CDK are activated independently and then act in concert to control Bax-mediated apoptosis.

Estramustine-related hypocalcemia in patients with prostate carcinoma and osteoblastic metastases

We describe a patient with androgen-independent prostate cancer in whom hypocalcemia developed during treatment with estramustine. The patient's total serum calcium level before and after the initiation of estramustine was 8.3 and 4.3 mg/dL, respectively (normal range 8.4 to 10.2). This finding prompted us to review the calcium levels in 135 consecutive patients who were also undergoing treatment with a similar estramustine-containing regimen. We found that hypocalcemia had developed in 20% of these patients during treatment. We speculate that estramustine may cause hypocalcemia by inhibiting the mobilization of calcium and the action of the parathyroid hormone in the skeleton.

NAIP protects the nigrostriatal dopamine pathway in an intrastriatal 6-OHDA rat model of Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder of the basal ganglia, associated with the inappropriate death of dopaminergic neurons of the substantia nigra pars compacta (SNc). Here, we show that adenovirally mediated expression of neuronal apoptosis inhibitor protein (NAIP) ameliorates the loss of nigrostriatal function following intrastriatal 6-OHDA administration by attenuating the death of dopamine neurons and dopaminergic fibres in the striatum. In addition, we also addressed the role of the cysteine protease caspase-3 activity in this adult 6-OHDA model, because a role for caspases has been implicated in the loss of dopamine neurons in PD, and because NAIP is also a reputed inhibitor of caspase-3. Although caspase-3-like proteolysis was induced in the SNc dopamine neurons of juvenile rats lesioned with 6-OHDA and in adult rats following axotomy of the medial forebrain bundle, caspase-3 is not induced in the dopamine neurons of adult 6-OHDA-lesioned animals. Taken together, these results suggest that therapeutic strategies based on NAIP may have potential value for the treatment of PD.

Effect of Nd:YAG laser irradiation on the apical leakage of obturated root canals: an electrochemical study

AIM

The purpose of this laboratory study was to evaluate the effect of Nd:YAG laser irradiation on the apical leakage of obturated root canals using an electrochemical method.

METHODOLOGY

Forty extracted single-rooted teeth were selected and the anatomic crown of each tooth was removed. The specimens were randomly divided into four groups. In group 1, the root canals were prepared with K-files and irradiated with Nd:YAG laser (5 W, 20 Hz) via a 300 microns optical fibre. Then the root canals were obturated with laterally condensed gutta-percha and Pulp Canal Sealer EWT. In group 2, the root canals were treated with the same method as those of group 1 but without laser irradiation. In group 3, the root canals were prepared with ProFiles, laser irradiated and then obturated with vertically condensed gutta-percha and Pulp Canal Sealer EWT. In group 4, the root canals were treated with the same method as those of group 3 but without laser irradiation. The electric resistance between standard and experimental electrodes in the canals was measured over a period of 10 days.

RESULTS

At 2 h, groups 1 and 3 irradiated with laser had significantly less apical leakage than group 2 (P < 0.05). After 10 days, group 4 had the highest leakage, followed by groups 2, 1 and 3; the differences between the groups was statistically significant (P < 0.05).

CONCLUSIONS

Laser irradiation following root canal preparation reduced apical leakage following root canal obturation.

Evidence that Myc isoforms transcriptionally repress caveolin-1 gene expression via an INR-dependent mechanism

The c-Myc oncoprotein contributes to oncogenesis by activating and repressing a repertoire of genes involved in cellular proliferation, metabolism, and apoptosis. Increasing evidence suggests that the repressor function of c-Myc is critical for transformation. Therefore, identifying and characterizing Myc-repressed genes is imperative to understanding the mechanisms of Myc-induced tumorigenesis. Here, we employ NIH 3T3 cell lines harboring c-Myc-ER or N-Myc-ER to dissect the relationship between Myc activation and caveolin-1 expression. In this well-established inducible system, treatment with estrogen like molecules, such as tamoxifen, leads to activation of Myc, but in a tightly controlled fashion. Using this approach, we show that Myc activation induces the repression of caveolin-1 expression at the transcriptional level. We also provide two independent lines of evidence suggesting that caveolin-1 is a direct target of Myc: (i) the effect of Myc activation on caveolin-1 expression is independent of new protein synthesis, as revealed through the use of cycloheximide; and (ii) Myc-mediated repression of the caveolin-1 promoter is dependent on an intact INR sequence. Moreover, we show that expression of caveolin-1, via an adenoviral vector approach, can suppress cell transformation that is mediated by Myc activation. In support of these observations, treatment with an adenoviral vector harboring anti-sense caveolin-1 specifically potentiates transformation induced by Myc activation. Taken together, our results indicate that caveolin-1 is a direct target of Myc repression, and they also provide evidence for an additional mechanism by which Myc repression can elicit a malignant phenotype.

Cell cycle regulators in neuronal death evoked by excitotoxic stress: implications for neurodegeneration and its treatment

Excitotoxic stress is potentially an important component of disorders such as stroke and neurodegenerative diseases. Its toxic effects appear to be transduced through mechanisms that result in both acute and delayed forms of death. We examined here whether cyclin dependent kinases (CDKs), molecules normally associated with cell cycle control, may be involved in delayed excitotoxic death in two different excitotoxin models. We show that nuclear localized cyclin D1, an activator of Cdk4/6, is upregulated during kainic acid evoked death of CA3/CA1 neurons and that this upregulation is associated with increased phosphorylation of a critical CDK substrate, pRb. In addition, we find that the CDK inhibitor, flavopiridol blocks the delayed death of cultured cortical neurons evoked by 3-nitroproprionic acid, an inhibitor of the mitochondrial electron transport chain, treatment and that the NMDA antagonist, MK801 provides short term protection in this model. Full, long-term protection occurs when both flavopiridol and MK-801 are present. Taken together, these data support a role for cell cycle regulators in neuronal death evoked by excitotoxic stress and indicate a potential therapeutic target for treatment of excitotoxicity-related disorders.