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1.
Eur Radiol ; 2024 Aug 23.
Article in English | MEDLINE | ID: mdl-39177856

ABSTRACT

OBJECTIVES: To investigate the association between magnetic resonance imaging (MRI)-based ligamentum teres lesions (LTL) and structural hip degeneration. METHODS: Bilateral 3-T hip MRIs of participants (n = 93 [36 men]; mean age ( ± SD) 51 years ± 15.4) recruited from the community and the orthopedic clinic of a single medical center were included. Clinical and imaging data acquired included hip disability and osteoarthritis outcome scores, semi-quantitative scoring of hip osteoarthritis on MRI (SHOMRI) scores on fluid-sensitive sequences, and cartilage T1ρ/T2 compositional sequences. An MRI-based LTL scoring system, incorporating continuity, thickening, and signal intensity, ranging from 0 (normal) to 4 (complete tear) was constructed. Hip morphological features associated with LTL, based on functional or anatomical relationships to LT, were defined. Relationships between MRI-LT scores and SHOMRI, global/regional cartilage T1ρ/T2, and proposed morphological abnormalities and LTL were explored by mixed effects linear and logistic regression models. RESULTS: In 82 (46.1%) hips, no pain was documented; 118 (63.4%) and 68 (36.6%) hips were graded as KL-grade ≤ 1 and ≥ 2, respectively. Compared to MRI-LT score = 0 (normal), score = 4 (complete tear) revealed significantly worse subchondral bony degenerative changes for bone marrow lesions (SHOMRI-BML) and subchondral cysts (SHOMRI-sc) (p < 0.001, p = 0.015, respectively). Global acetabular T1ρ, femoral T2 were significantly increased for abnormal MRI-LT scores (p-range = 0.005-0.032). Regional analyses revealed significantly increased T1ρ/T2 in central acetabular/increased T2 in off-central femoral regions (p-range = 0.005-0.046). Pulvinar effusion-synovitis, shallow fovea, and foveal osteophytes were significantly associated with abnormal LT MRI findings (p-range = < 0.001-0.044). CONCLUSION: MRI abnormalities of LT are associated with worse SHOMRI-sc/BML scores, indicative of hip osteoarthritis and higher T1ρ and T2 that differ by region. Pulvinar effusion-synovitis and changes in femoral head morphology are associated with LTL. CLINICAL RELEVANCE STATEMENT: Abnormal ligamentum teres findings identified via MRI are associated with structural degenerative changes of the hip joint and alterations in acetabular and femoral cartilage compositions show spatial differences in relation to LTL. KEY POINTS: The clinical significance of common ligamentum teres lesions (LTL) on MRI is not well understood. LTL identified by an MRI-based scoring system is associated with worse biomarkers, indicating more advanced degenerative hip changes. Effusion-synovitis signal at pulvinar, shallow fovea capitis, and foveal osteophytes are associated with LTL on imaging.

2.
J Magn Reson Imaging ; 57(4): 1042-1053, 2023 04.
Article in English | MEDLINE | ID: mdl-35852477

ABSTRACT

BACKGROUND: Although T1ρ and T2 have emerged as early indicators for hip osteoarthritis (OA), there is little information regarding longitudinal changes across the cartilage in the early stages of this disease. PURPOSE: To characterize the variability in 2-year hip cartilage T1ρ and T2 changes and investigate associations between these patterns of change and common indicators of hip OA. STUDY TYPE: Prospective. POPULATION: A total of 25 women (age: 51.9 ± 16.3 years old; BMI: 22.6 ± 2.0 kg/m2 ) and 17 men (age: 55.8 ± 14.9 years old; body mass index (BMI): 24.4 ± 3.8 kg/m2 ) who were healthy or with early-to-moderate hip OA. FIELD STRENGTH/SEQUENCE: A 3 T MRI (GE), 3D combined T1ρ /T2 magnetization-prepared angle-modulated partitioned k-space spoiled gradient echo snapshots. ASSESSMENT: Principal component (PC) analysis of Z-score difference maps of 2-year changes in hip cartilage T1ρ and T2 relaxation times, participant hip disability and osteoarthritis outcome scores (HOOS) and functional tests at 2-year follow-up. STATISTICAL TESTS: Shapiro-Wilk test, unpaired t-tests, Kruskal Wallis tests, Pearson or Spearman (ρ) correlations. Significance was set at P < 0.05. RESULTS: Women (-6.40 ± 14.48) had significantly lower T1ρ PC1 scores than men (10.05 ± 26.15). T1ρ PC4 was significantly correlated with HOOSsport , HOOSsymptoms , HOOSpain , HOOSadl , and HOOSqol at 2-year follow-up (ρ: [0.36, 0.50]). T1ρ PC2 and PC4 were significantly correlated with 30-second chair test (ρ = -0.39 and ρ = 0.24, respectively) and side plank (ρ = -0.32 and ρ = 0.21). T1ρ and T2 PC2 were significantly correlated with 40 m walk test (ρ = 0.34 and ρ = 0.31) and 30-second chair rise test (ρ = -0.39 and ρ = -0.32). DATA CONCLUSION: Men exhibited accelerated T1ρ increases across the femoral cartilage compared to women, suggesting sex should be considered when evaluating early hip OA. Participants with poorer HOOS and function exhibited greater T1ρ and T2 increases in superior and anterior femoral cartilage and greater T1ρ increases in the anterior femoral cartilage. These patterns of short-term relaxometry increases could indicate hip OA progression. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 3.


Subject(s)
Cartilage, Articular , Osteoarthritis, Hip , Male , Humans , Female , Adult , Middle Aged , Aged , Magnetic Resonance Imaging , Body Mass Index , Bone and Bones
3.
J Magn Reson Imaging ; 2023 Sep 13.
Article in English | MEDLINE | ID: mdl-37702305

ABSTRACT

BACKGROUND: The polyarticular nature of Osteoarthritis (OA) tends to manifest in multi-joints. Associations between cartilage health in connected joints can help identify early degeneration and offer the potential for biomechanical intervention. Such associations between hip and knee cartilages remain understudied. PURPOSE: To investigate T1p associations between hip-femoral and acetabular-cartilage subregions with Intra-limb and Inter-limb patellar cartilage; whole and deep-medial (DM), deep-lateral (DL), superficial-medial (SM), superficial-lateral (SL) subregions. STUDY TYPE: Prospective. SUBJECTS: Twenty-eight subjects (age 55.1 ± 12.8 years, 15 females) with none-to-moderate hip-OA while no radiographic knee-OA. FIELD STRENGTH/SEQUENCE: 3-T, bilateral hip, and knee: 3D-proton-density-fat-saturated (PDFS) Cube and Magnetization-Prepared-Angle-Modulated-Partitioned-k-Space-Spoiled-Gradient-Echo-Snapshots (MAPSS). ASSESSMENT: Ages of subjects were categorized into Group-1 (≤40), Group-2 (41-50), Group-3 (51-60), Group-4 (61-70), Group-5 (71-80), and Group-6 (≥81). Hip T1p maps, co-registered to Cube, underwent an atlas-based algorithm to quantify femoral and acetabular subregional (R2 -R7 ) cartilage T1p . For knee Cube, a combination of V-Net architectures was used to segment the patellar cartilage and subregions (DM, DL, SM, SL). T1p values were computed from co-registered MAPSS. STATISTICAL TESTS: For Intra-and-Inter-limb, 5 optimum predictors out of 13 (Hip subregional T1p , age group, gender) were selected by univariate linear-regression, to predict outcome (patellar T1p ). The top five predictors were stepwise added to six linear mixed-effect (LME) models. In all LME models, we assume the data come from the same subject sharing the same random effect. The best-performing models (LME-modelbest ) selected via ANOVA, were tested with DM, SM, SL, and DL subregional-mean T1p . LME assumptions were verified (normality of residuals, random-effects, and posterior-predictive-checks). RESULTS: LME-modelbest (Intra-limb) had significant negative and positive fixed-effects of femoral-R5 and acetabular-R2 T1p , respectively (conditional-R2 = 0.581). LME-modelbest (Inter-limb) had significant positive fixed-effects of femoral-R3 T1p (conditional-R2 = 0.26). DATA CONCLUSION: Significant positive and negative T1p associations were identified between load-bearing hip cartilage-subregions vs. ipsilateral and contralateral patellar cartilages respectively. The effects were localized on medial subregions of Inter-limb, in particular. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 1.

4.
Br J Dermatol ; 183(1): 146-154, 2020 07.
Article in English | MEDLINE | ID: mdl-31605618

ABSTRACT

BACKGROUND: Skin tears are acute wounds that are frequently misdiagnosed and under-reported. A standardized and globally adopted skin tear classification system with supporting evidence for diagnostic validity and reliability is required to allow assessment and reporting in a consistent way. OBJECTIVES: To measure the validity and reliability of the International Skin Tear Advisory Panel (ISTAP) Classification System internationally. METHODS: A multicountry study was set up to validate the content of the ISTAP Classification System through expert consultation in a two-round Delphi procedure involving 17 experts from 11 countries. An online survey including 24 skin tear photographs was conducted in a convenience sample of 1601 healthcare professionals from 44 countries to measure diagnostic accuracy, agreement, inter-rater reliability and intrarater reliability of the instrument. RESULTS: A definition for the concept of a 'skin flap' in the area of skin tears was developed and added to the initial ISTAP Classification System consisting of three skin tear types. The overall agreement with the reference standard was 0·79 [95% confidence interval (CI) 0·79-0·80] and sensitivity ranged from 0·74 (95% CI 0·73-0·75) to 0·88 (95% CI 0·87-0·88). The inter-rater reliability was 0·57 (95% CI 0·57-0·57). The Cohen's Kappa measuring intrarater reliability was 0·74 (95% CI 0·73-0·75). CONCLUSIONS: The ISTAP Classification System is supported by evidence for validity and reliability. The ISTAP Classification System should be used for systematic assessment and reporting of skin tears in clinical practice and research globally. What's already known about this topic? Skin tears are common acute wounds that are misdiagnosed and under-reported too often. A skin tear classification system is needed to standardize documentation and description for clinical practice, audit and research. What does this study add? The International Skin Tear Advisory Panel Classification System was psychometrically tested in 1601 healthcare professionals from 44 countries. Diagnostic accuracy was high when differentiating between type 1, 2 and 3 skin tears using a set of validated photographs.


Subject(s)
Lacerations , Soft Tissue Injuries , Humans , Lacerations/diagnosis , Reproducibility of Results , Skin/injuries , Surveys and Questionnaires
5.
Vestn Otorinolaringol ; 84(1): 68-71, 2019.
Article in Russian | MEDLINE | ID: mdl-30938347

ABSTRACT

Laryngitis is one of the commonest causes of dysphonia in the subjects engaged in the voice and speech professions. This condition can be either associated with the professional activities or related to voice fatigue. It is a common practice to distinguish between acute and chronic forms of occupational laryngitis. The main factors responsible for development of both conditions include the non-observance of directions concerning the protection and hygiene of the speaking and singing voice. The present study included 478 (100%) subjects engaged in the voice and speech professions presenting with the diagnosis of acute or chronic occupational laryngitis who applied for medical assistance to our Phoniatric Care Department. The clinical state of their larynx was evaluated with the use of the videoendostroboscopic technique. Acute laryngitis was diagnosed in 103 (21.5%) of the examined subjects while the remaining 375 (78.5%) ones presented with chronic laryngitis. A characteristic feature of acute occupational laryngitis documented in 38 (36.9%) examined professional voice users with this condition (practically healthy in all other respects) was the development of this disorder as a result of overloading the speech organs. On the contrary, viral and/or bacterial laryngitis revealed in 65 (63.1%) of the patients was preceded by acute respiratory symptoms. A total of 62 (16.5%) patients suffered from chronic occupational laryngitis attributable to overloading of the organs of speech during protracted periods. The remaining 313 examined professional voice users were found to present with various forms of chronic laryngitis including catarrhal laryngitis in 175 (46.7%) of them, edematous-polypoid and atrophic forms in 32 (8.5%) and 19 (5.1%) subjects respectively. The main etiological factors underlying the development of all the tree forms of chronic laryngitis were smoking, chronic tonsillitis, gastroesophageal reflux disease, bronchial asthma, and diabetes mellitus.


Subject(s)
Dysphonia , Laryngitis , Singing , Voice Disorders , Chronic Disease , Dysphonia/etiology , Dysphonia/therapy , Humans , Laryngitis/complications , Speech , Voice Disorders/etiology , Voice Disorders/therapy
6.
Vestn Otorinolaringol ; 82(3): 48-53, 2017.
Article in Russian | MEDLINE | ID: mdl-28631682

ABSTRACT

The objective of the present study was to evaluate the effectiveness of the application of homeovox for the combined treatment of small vocal cord nodules and acute laryngitis in the professional voice users. A total of 40 subjects presenting with dysphonia were examined after they were divided into two study groups and two groups of comparison depending on the nosological form of the pathological condition. The subjects comprising the study groups were given traditional therapy in the combination with the intake of homeovox whereas the patients included in the two groups of comparison received the traditional treatment alone. The outcome of the treatment was evaluated on days 1, 5, and 10 after the initiation of therapy based on the analysis of the changes in the videoendostroboscopic picture of the larynx and the acoustic characteristics obtained by the computer-assisted analysis of the voice. The analysis of the results of the combined treatment has demonstrated the statistically significant differences in some acoustic parameters of the voice between the subjects with small vocal cord nodules and acute laryngitis belonging to the study groups and the groups of comparison. It is concluded that the introduction of homeovox in the combined treatment of the patients presenting with the small nodules in the vocal cords and acute catarrhal laryngitis accelerates the recovery of the acoustic characteristics of the voice within various periods after the onset of the treatment in comparison with the patients treated with the use of traditional therapy alone.


Subject(s)
Dysphonia , Materia Medica/administration & dosage , Occupational Diseases , Voice Quality/drug effects , Adult , Anti-Inflammatory Agents/administration & dosage , Drug Monitoring , Drug Therapy, Combination/methods , Dysphonia/diagnosis , Dysphonia/drug therapy , Dysphonia/etiology , Dysphonia/physiopathology , Expectorants/administration & dosage , Female , Humans , Laryngoscopy/methods , Male , Middle Aged , Occupational Diseases/diagnosis , Occupational Diseases/drug therapy , Occupational Diseases/etiology , Occupational Diseases/physiopathology , Treatment Outcome
7.
Lupus ; 25(11): 1209-16, 2016 Oct.
Article in English | MEDLINE | ID: mdl-26957351

ABSTRACT

BACKGROUND: Glucocorticoids have been known for years to be the most effective therapy in systemic lupus erythematosus. Their use, however, is limited by the need for high doses due to their unfavorable pharmacokinetics and biodistribution. We have previously developed a novel liposome-based steroidal (methylprednisolone hemisuccinate (MPS)) nano-drug and demonstrated its specific accumulation in inflamed tissues, as well as its superior therapeutic efficacy over that of free glucocorticoids (non-liposomal) in the autoimmune diseases, including the adjuvant arthritis rat model and the experimental autoimmune encephalomyelitis mouse model. OBJECTIVES: In the present work we have evaluated the therapeutic effect of the above liposome-based steroidal (MPS) nano-drug in the MRL-lpr/lpr murine model of SLE and compared it with similar doses of the free MPS. METHODS: MRL-lpr/lpr mice were treated with daily injections of free MPS or weekly injections of 10% dextrose, empty nano-liposomes or the steroidal nano-drug and the course of their disease was followed up to the age of 24 weeks. RESULTS: Treatment with the steroidal nano-drug was found to be significantly superior to the free MPS in suppressing anti-dsDNA antibody levels, proliferation of lymphoid tissue and renal damage, and in prolonging survival of animals. CONCLUSION: This significant superiority of our liposome based steroidal nano-drug administered weekly compared with daily injections of free methylprednisolone hemisuccinate in suppressing murine lupus indicates this glucocorticoid nano-drug formulation may be a good candidate for the treatment of human SLE.


Subject(s)
Lupus Erythematosus, Systemic/drug therapy , Methylprednisolone Hemisuccinate/administration & dosage , Nanoparticles/administration & dosage , Animals , Antibodies, Antinuclear/metabolism , Disease Models, Animal , Drug Administration Schedule , Female , Liposomes/administration & dosage , Lupus Erythematosus, Systemic/immunology , Lupus Erythematosus, Systemic/metabolism , Mice , Mice, Inbred MRL lpr , Treatment Outcome
8.
J Biomech Eng ; 138(9)2016 09 01.
Article in English | MEDLINE | ID: mdl-27455417

ABSTRACT

Measurements of joint kinematics are essential to understand the pathomechanics of ankle disease and the effects of treatment. Traditional motion capture techniques do not provide measurements of independent tibiotalar and subtalar joint motion. In this study, high-speed dual fluoroscopy images of ten asymptomatic adults were acquired during treadmill walking at 0.5 m/s and 1.0 m/s and a single-leg, balanced heel-rise. Three-dimensional (3D) CT models of each bone and dual fluoroscopy images were used to quantify in vivo kinematics for the tibiotalar and subtalar joints. Dynamic tibiotalar and subtalar mean joint angles often exhibited opposing trends during captured stance. During both speeds of walking, the tibiotalar joint had significantly greater dorsi/plantarflexion (D/P) angular ROM than the subtalar joint while the subtalar joint demonstrated greater inversion/eversion (In/Ev) and internal/external rotation (IR/ER) than the tibiotalar joint. During balanced heel-rise, only D/P and In/Ev were significantly different between the tibiotalar and subtalar joints. Translational ROM in the anterior/posterior (AP) direction was significantly greater in the subtalar than the tibiotalar joint during walking at 0.5 m/s. Overall, our results support the long-held belief that the tibiotalar joint is primarily responsible for D/P, while the subtalar joint facilitates In/Ev and IR/ER. However, the subtalar joint provided considerable D/P rotation, and the tibiotalar joint rotated about all three axes, which, along with translational motion, suggests that each joint undergoes complex, 3D motion.


Subject(s)
Ankle Joint/diagnostic imaging , Ankle Joint/physiology , Fluoroscopy/methods , Imaging, Three-Dimensional/methods , Range of Motion, Articular/physiology , Subtalar Joint/diagnostic imaging , Subtalar Joint/physiology , Female , Humans , Male , Radiographic Image Interpretation, Computer-Assisted/methods , Reference Values , Reproducibility of Results , Sensitivity and Specificity
9.
Inflammopharmacology ; 23(5): 271-81, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26223507

ABSTRACT

The oxidant scavenging ability (OSA) of catalase-rich Candida albicans is markedly enhanced by chlorhexidine digluconate (CHX), polymyxin B, the bile salt ursodeoxycholate and by lysophosphatidylcholine, which all act as detergents facilitating the penetration of oxidants and their intracellular decomposition. Quantifications of the OSA of Candida albicans were measured by a highly sensitive luminol-dependent chemiluminescence assay and by the Thurman's assay, to quantify hydrogen peroxide (H2O2). The OSA enhancing activity by CHX depends to some extent on the media on which candida grew. The OSA of candida treated by CHX was modulated by whole human saliva, red blood cells, lysozyme, cationic peptides and by polyphenols. Concentrations of CHX, which killed over 95 % of Candida albicans cells, did not affect the cells' abilities to scavenge reactive oxygen species (ROS). The OSA of Candida cells treated by CHX is highly refractory to H2O2 (50 mM) but is strongly inhibited by hypochlorous acid, lecithin, trypan blue and by heparin. We speculate that similarly to catalase-rich red blood cells, Candida albicans and additional catalase-rich microbiota may also have the ability to scavenge oxidants and thus can protect catalase-negative anaerobes and facultative anaerobes cariogenic streptococci against peroxide and thus secure their survival in the oral cavity.


Subject(s)
Candida albicans/metabolism , Chlorhexidine/analogs & derivatives , Free Radical Scavengers/metabolism , Oxidants/metabolism , Chlorhexidine/administration & dosage , Chlorhexidine/metabolism , Dose-Response Relationship, Drug , Drug Synergism , Free Radical Scavengers/administration & dosage , Humans , Oxidants/antagonists & inhibitors , Reactive Oxygen Species/metabolism
10.
Vestn Otorinolaringol ; (1): 44-47, 2015.
Article in Russian | MEDLINE | ID: mdl-25909674

ABSTRACT

We have undertaken the electron microscopic investigation into peculiarities of six tumour-like structures on the vocal cords. The study has demonstrated changes in the number and distribution patterns of intercellular junctions, keratin and tonofilament contents in epithelial cells, basal membrane structure, and composition of the basic substance in lamina propria. All the examined tumour-like structures contained bacteria an two of them had viral particles in vacuoles of fibroblasts. Moreover, the bacteria were found on the surface of epithelium, between epithelial cells and in the basic substance in lamina propria. Cytoplasm of epithelial cells and fibroblasts not infrequently contained bacteria in the phase of division.


Subject(s)
Laryngeal Neoplasms/microbiology , Laryngeal Neoplasms/ultrastructure , Vocal Cords/ultrastructure , Humans , Microscopy, Electron
11.
Magn Reson Imaging ; 111: 237-245, 2024 Sep.
Article in English | MEDLINE | ID: mdl-38636675

ABSTRACT

Limited information exists regarding abductor muscle quality variation across its length and which locations are most representative of overall muscle quality. This is exacerbated by time-intensive processes for manual muscle segmentation, which limits feasibility of large cohort analyses. The purpose of this study was to develop an automated and localized analysis pipeline that accurately estimates hip abductor muscle quality and size in individuals with mild-to-moderate hip osteoarthritis (OA) and identifies regions of each muscle which provide best estimates of overall muscle quality. Forty-four participants (age 52.7 ± 16.1 years, BMI 23.7 ± 3.4 kg/m2, 14 males) with and without mild-to-moderate radiographic hip OA were recruited for this study. Unilateral hip magnetic resonance (MR) images were acquired on a 3.0 T MR scanner and included axial T1-weighted fast spin echo and 3D axial Iterative Decomposition of water and fat with Echo Asymmetry and Least-squares estimation (IDEAL-IQ) spoiled gradient-recalled echo (SPGR) with multi-peak fat spectrum modeling and single T2* correction. A three dimensional (3D) V-Net convolutional neural network was trained to automatically segment the gluteus medius (GMED), gluteus minimus (GMIN), and tensor fascia lata (TFL) on axial IDEAL-IQ. Agreement between manual and automatic segmentation and associations between axial fat fraction (FF) estimated from IDEAL-IQ and overall muscle FF were evaluated. Dice scores for automatic segmentation were 0.94, 0.87, and 0.91 for GMED, GMIN, and TFL, respectively. GMED, GMIN, and TFL volumetric and FF measures were strongly correlated (r: 0.92-0.99) between automatic and manual segmentations, where all values fell within the 95% limits of agreement of [-9.79 cm3, 17.43 cm3] and [-1.99%, 2.89%], respectively. Axial FF was significantly associated with overall FF with the strongest correlations at 50%, 50%, and 65% the length of the GMED, GMIN, and TFL muscles, respectively (r: 0.93-0.97). An automated and localized analysis can provide efficient and accurate estimates of hip abductor muscle quality and size across muscle length. Specific regions of the muscle may be used to estimate overall muscle quality in an abbreviated evaluation of muscle quality.


Subject(s)
Magnetic Resonance Imaging , Muscle, Skeletal , Osteoarthritis, Hip , Humans , Male , Middle Aged , Female , Magnetic Resonance Imaging/methods , Muscle, Skeletal/diagnostic imaging , Muscle, Skeletal/pathology , Osteoarthritis, Hip/diagnostic imaging , Osteoarthritis, Hip/pathology , Adult , Aged , Image Processing, Computer-Assisted/methods , Hip/diagnostic imaging , Hip/pathology
12.
Nano Lett ; 11(1): 183-7, 2011 Jan 12.
Article in English | MEDLINE | ID: mdl-21126102

ABSTRACT

Semiconducting nanowires grown by the vapor-liquid-solid method commonly develop nonuniform doping profiles both along the growth axis and radially due to unintentional surface doping and diffusion of the dopants from the nanowire surface to core during synthesis. We demonstrate two approaches to mitigate nonuniform doping in phosphorus-doped Si nanowires grown by the vapor-liquid-solid process. First, the growth conditions can be modified to suppress active surface doping. Second, thermal annealing following growth can be used to produce more uniform doping profiles. Kelvin probe force microscopy and scanning photocurrent microscopy were used to measure the radial and the longitudinal active dopant distribution, respectively. Doping concentration variations were reduced by 2 orders of magnitude in both annealed nanowires and those for which surface doping was suppressed.

13.
Nano Lett ; 11(6): 2499-502, 2011 Jun 08.
Article in English | MEDLINE | ID: mdl-21591656

ABSTRACT

The potential of the metal nanocatalyst to contaminate vapor-liquid-solid (VLS) grown semiconductor nanowires has been a long-standing concern, since the most common catalyst material, Au, is known to induce deep gap states in several semiconductors. Here we use Kelvin probe force microscopy to image individual deep acceptor type trapping centers in single undoped Si nanowires grown with an Au catalyst. The switching between occupied and empty trap states is reversibly controlled by the back-gate potential in a nanowire transistor. The trap energy level, i.e., E(C) - E(T) = 0.65 ± 0.1 eV was extracted and the concentration was estimated to be ∼2 × 10(16) cm(-3). The energy and concentration are consistent with traps resulting from the unintentional incorporation of Au atoms during the VLS growth.


Subject(s)
Nanowires/chemistry , Silicon/chemistry , Catalysis , Gold/chemistry , Semiconductors , Surface Properties , Transistors, Electronic
14.
Foot Ankle Int ; 43(6): 818-829, 2022 06.
Article in English | MEDLINE | ID: mdl-35293257

ABSTRACT

BACKGROUND: In vivo measurements of tibiotalar and subtalar joint motion following TAR are unavailable. Using biplane fluoroscopy, we tested the hypothesis that the prosthetic tibiotalar joint and adjacent subtalar joint would demonstrate kinematic and range of motion differences compared to the contralateral untreated limb, and control participants. METHODS: Six patients of 41 identified candidates that all underwent unilateral Zimmer TAR (5.4 ± 1.9 years prior) and 6 control participants were imaged with biplane fluoroscopy during overground walking and a double heel-rise activity. Computed tomography scans were acquired; images were segmented and processed to serve as input for model-based tracking of the biplane fluoroscopy data. Measurements included tibiotalar and subtalar kinematics for the TAR, untreated contralateral, and control limbs. Statistical parametric mapping quantified differences in kinematics throughout overground walking and the double heel-rise activity. RESULTS: Patients with this TAR performed walking and heel-rise activities symmetrically with no significant kinematic differences at the tibiotalar and subtalar joints between limbs. Compared to control participants, patients exhibited reduced dorsi/plantarflexion range of motion that corresponded to decreased peak dorsiflexion, but only in the late stance phase of walking. This reduction in tibiotalar dorsi/plantarflexion range of motion in the TAR group became more apparent with double heel-rise activity. CONCLUSION: Patients with a Zimmer TAR had symmetric kinematics during activities of walking and double heel-rise, but they did exhibit minor compensations in tibiotalar kinematics as compared to controls. CLINICAL RELEVANCE: The lack of significant kinematic compensation at the subtalar joint may explain why secondary subtalar osteoarthritis is reported as being relatively uncommon in patients with some TAR designs.


Subject(s)
Arthroplasty, Replacement, Ankle , Osteoarthritis , Subtalar Joint , Ankle Joint/diagnostic imaging , Biomechanical Phenomena , Fluoroscopy/methods , Humans , Range of Motion, Articular , Subtalar Joint/diagnostic imaging , Subtalar Joint/surgery
15.
J Orthop Res ; 40(8): 1744-1755, 2022 08.
Article in English | MEDLINE | ID: mdl-34820897

ABSTRACT

The aims of this case-control study were to: (1) Identify cartilage locations and volumes at risk of osteoarthritis (OA) using subject-specific finite element (FE) models; (2) Quantify the relationships between the simulated biomechanical parameters and T2 and T1ρ relaxation times of magnetic resonance imaging (MRI). We created subject-specific FE models for seven patients with anterior cruciate ligament (ACL) reconstruction and six controls based on a previous proof-of-concept study. We identified locations and cartilage volumes susceptible to OA, based on maximum principal stresses and absolute maximum shear strains in cartilage exceeding thresholds of 7 MPa and 32%, respectively. The locations and volumes susceptible to OA were compared qualitatively and quantitatively against 2-year longitudinal changes in T2 and T1ρ relaxation times. The degeneration volumes predicted by the FE models, based on excessive maximum principal stresses, were significantly correlated (r = 0.711, p < 0.001) with the degeneration volumes determined from T2 relaxation times. There was also a significant correlation between the predicted stress values and changes in T2 relaxation time (r = 0.649, p < 0.001). Absolute maximum shear strains and changes in T1ρ relaxation time were not significantly correlated. Five out of seven patients with ACL reconstruction showed excessive maximum principal stresses in either one or both tibial cartilage compartments, in agreement with follow-up information from MRI. Expectedly, for controls, the FE models and follow-up information showed no degenerative signs. Our results suggest that the presented modelling methodology could be applied to prospectively identify ACL reconstructed patients at risk of biomechanically driven OA, particularly by the analysis of maximum principal stresses of cartilage.


Subject(s)
Anterior Cruciate Ligament Injuries , Cartilage, Articular , Osteoarthritis , Anterior Cruciate Ligament Injuries/diagnostic imaging , Anterior Cruciate Ligament Injuries/pathology , Anterior Cruciate Ligament Injuries/surgery , Cartilage, Articular/pathology , Case-Control Studies , Finite Element Analysis , Follow-Up Studies , Humans , Knee Joint/surgery , Magnetic Resonance Imaging/methods , Osteoarthritis/diagnostic imaging , Osteoarthritis/pathology
16.
J Orthop Res ; 39(8): 1722-1731, 2021 08.
Article in English | MEDLINE | ID: mdl-33615524

ABSTRACT

Clinicians often examine movement patterns to design hip osteoarthritis (OA) interventions, yet traditional biomechanical analyses only report a single timepoint. Multivariate principal component analysis (MFPCA) analyzes the entire waveform (i.e., movement pattern), which clinicians observe to direct treatment. This study investigated hip OA indicators, by (1) employing MFPCA to characterize variance across the hip, knee, and ankle angles in healthy and early-to-moderate hip OA participants; and (2) investigating relationships between these waveform features and hip cartilage health. Bilateral hip magnetic resonance images from 72 participants with Kellgren-Lawrence grades ranging from 0 to 3 were used to calculate mean T 1ρ and T 2 relaxation times in the femoral and acetabular cartilage. MFPCA was performed on lower-limb gait biomechanics and used to identify primary modes of variation, which were related to T 1ρ and T 2 relaxation times. Here, a MFPC = mode of variation = waveform feature. In the femoral cartilage, transverse plane MFPCs 3 and 5 and body mass index (BMI) was related to T 1ρ , while MFPC 2 and BMI were related to T 2 relaxation times. In the acetabular cartilage, sagittal plane MFPC 1 and BMI were related to T 1ρ , while BMI was related to T 2 relaxation times. Greater internal rotation was related to increased T 1ρ and T 2 relaxation times in the femoral cartilage, while the greater extension was related to increased T 1ρ relaxation times in the acetabular cartilage. This study established a data-driven framework to assess relationships between multi-joint biomechanics and quantitative assessments of cartilage health and identified waveform features that could be evaluated in future hip OA intervention studies.


Subject(s)
Cartilage, Articular , Osteoarthritis, Hip , Osteoarthritis, Knee , Biomechanical Phenomena , Cartilage, Articular/pathology , Gait , Humans , Magnetic Resonance Imaging/methods , Osteoarthritis, Knee/pathology , Principal Component Analysis
17.
Gait Posture ; 85: 258-265, 2021 03.
Article in English | MEDLINE | ID: mdl-33626450

ABSTRACT

BACKGROUND: Several multi-segment foot models have been developed to evaluate foot and ankle motion using skin-marker motion analysis. However, few multi-segment models have been evaluated against a reference standard to establish kinematic accuracy. RESEARCH QUESTION: How accurately do skin-markers estimate foot and ankle motion for the modified Shriners Hospitals for Children Greenville (mSHCG) multi-segment foot model when compared against the reference standard, dual fluoroscopy (DF), during gait, in asymptomatic participants? METHODS: Five participants walked overground as full-body skin-marker trajectory data and DF images of the foot and shank were simultaneously acquired. Using the mSHCG model, ankle and midfoot angles were calculated throughout stance for both motion analysis techniques. Statistical parametric mapping assessed differences in joint angles and marker positions between skin-marker and DF motion analysis techniques. Paired t tests, and linear regression models were used to compare joint angles and range of motion (ROM) calculated from the two techniques. RESULTS: In the coronal plane, the skin-marker model significantly overestimated ROM (p = 0.028). Further, the DF model midfoot ROM was significantly positively related to differences between DF and skin-marker midfoot angles (p = 0.035, adjusted R2 = 0.76). In the sagittal plane, skin-markers underestimated ankle angles by as much as 7.26°, while midfoot angles were overestimated by as much as 9.01°. However, DF and skin-marker joint angles were not significantly different over stance. Skin-markers on the tibia, calcaneus, and fifth metatarsal had significantly different positions than the DF markers along the direction of walking for isolated portions that were less than 10 % of stance. Euclidean distances between DF and skin-markers positions were less than 9.36 mm. SIGNIFICANCE: As the accuracy of the mSHCG model was formerly unknown, the results of this study provide ranges of confidence for key angles calculated by this model.


Subject(s)
Ankle Joint/diagnostic imaging , Foot/diagnostic imaging , Physical Therapy Modalities , Walking/physiology , Ankle Joint/anatomy & histology , Biomechanical Phenomena , Fluoroscopy , Foot/anatomy & histology , Humans , Range of Motion, Articular , Reference Standards , Reproducibility of Results , Young Adult
18.
Med Law ; 29(4): 537-46, 2010 Dec.
Article in English | MEDLINE | ID: mdl-22145549

ABSTRACT

How do carers know what is right for their patient? What can they do further to relying on the two pillars of knowledge and ethics? Knowledge foregrounds rational decision-making based on scientific evidence. It allows cost-benefit rationalization and the choice of the best feasible objective. The steady advance of medical science drives responsible carers to keep their knowledge and skills up-to-date. Bioethics grants primary attention to the prevention of causing harm in general, to pursuant of patients' subjective wellbeing and to allow the latter enjoy their autonomy and to guarantee them the sense of justice. There are, however, cases where these values collide and any care decision violates one principle or another. How are carers expected to act then? This article concerns the choices made by carers, as presented and discussed in two cases. These cases deal with a clash between two principles: parenthood vs. fertility, religious rite vs. social affiliation. This class has generated an ethical dilemma. In each case carers try to justify their choices by expert knowledge and other ethical values, but later reflection reveals that the predominant element in 'solving' these dilemmas was "emotions." Professional training submits that: 'Set aside feelings in order to keep your thinking 'straight.' However, reality proves this simply infeasible. The more complex the medical-ethical situation, it is more likely that "emotions" take over. We have no choice as responsible carers but to allow our emotions the status of a factor of influence in their own right. Nowadays, a basic medical training for doctors and nurses offers an integrated body of knowledge and therapeutic skills. In addition, trainees are introduced to bioethics, supposedly sufficient to guide their future steps in their chosen profession. But how does this training in fact shape their future ethical conduct, if at all? How does it affect their ability to maintain ethical responsibility throughout therapeutic interactions? Perhaps there are other factors which govern the individual's conduct and his/her ethical responsibility? Simulation exercises were conducted, designed to induce healthcare professionals to reflect on the ethics of their own decision-making. The results demonstrated that therapeutic skills and familiarity with bioethical principles are not the sole factors governing the individual's ethical conduct. It turns out that emotions and feelings play a key part; this at once raises the question as to whether a medical training for doctors and nurses, in its current format, concerns itself with emotions and with how emotions shape a therapeutic personality. If not, then our training designers have food for thought. How can such training make trainees more aware of the power of their emotions? And, what are the ramifications on daily practice concerning ethical responsibility? Another question concerns the possible proper methods for mastering the theoretical materials and the practical techniques that promote emotional self-development?


Subject(s)
Bioethical Issues , Empathy , Professional-Patient Relations , Social Values , Emotions , Humans , Judgment
19.
J Bone Joint Surg Am ; 102(7): 600-608, 2020 Apr 01.
Article in English | MEDLINE | ID: mdl-32079879

ABSTRACT

BACKGROUND: Tibiotalar arthrodesis is a common treatment for end-stage tibiotalar osteoarthritis, and is associated with a long-term risk of concomitant subtalar osteoarthritis. It has been clinically hypothesized that subtalar osteoarthritis following tibiotalar arthrodesis is the product of compensatory subtalar joint hypermobility. However, in vivo measurements of subtalar joint motion following tibiotalar arthrodesis have not been quantified. Using dual-fluoroscopy motion capture, we tested the hypothesis that the subtalar joint of the limb with a tibiotalar arthrodesis would demonstrate differences in kinematics and increased range of motion compared with the subtalar joint of the contralateral, asymptomatic, untreated ankle. METHODS: Ten asymptomatic patients who had undergone unilateral tibiotalar arthrodesis at a mean (and standard deviation) of 4.0 ± 1.8 years previously were evaluated during overground walking and a double heel-rise task. The evaluation involved markerless tracking with use of dual fluoroscopy integrated with 3-dimensional computed tomography, which allowed for dynamic measurements of subtalar and tibiotalar dorsiflexion-plantar flexion, inversion-eversion, and internal-external rotation. Range of motion, stance time, swing time, step length, and step width were also measured. RESULTS: During the early stance phase of walking, the subtalar joint of the limb that had been treated with arthrodesis was plantar flexed (-4.7° ± 3.3°), whereas the subtalar joint of the untreated limb was dorsiflexed (4.6° ± 2.2°). Also, during the early stance phase of walking, eversion of the subtalar joint of the surgically treated limb (0.2° ± 2.3°) was less than that of the untreated limb (4.5° ± 3.2°). During double heel-rise, the treated limb exhibited increased peak subtalar plantar flexion (-7.1° ± 4.1°) compared with the untreated limb (0.2° ± 1.8°). CONCLUSIONS: A significant increase in subtalar joint plantar flexion was found to be a primary compensation during overground walking and a double heel-rise activity following tibiotalar arthrodesis. CLINICAL RELEVANCE: Significant subtalar joint plantar flexion compensations appear to occur following tibiotalar arthrodesis. We found an increase in subtalar plantar flexion and considered the potential relationship of this finding with the increased rate of subtalar osteoarthritis that occurs following ankle arthrodesis.


Subject(s)
Arthrodesis , Osteoarthritis/surgery , Range of Motion, Articular , Subtalar Joint/diagnostic imaging , Subtalar Joint/physiology , Talus/surgery , Tibia/surgery , Adult , Cohort Studies , Female , Fluoroscopy/methods , Humans , Male , Middle Aged , Osteoarthritis/etiology , Postoperative Complications/etiology , Retrospective Studies , Walking
20.
Clin Exp Immunol ; 157(1): 155-64, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19659781

ABSTRACT

Hepatic fibrosis is the end-stage consequence of chronic liver disease, affecting many people worldwide. Unlike the anti-fibrotic effect of natural killer (NK) cells, CD8 and NK T subsets are considered as profibrogenic subsets. Padma Hepaten is a multi-compound herbal preparation derived from Tibetan medicine and has proven efficacy in some clinical trials and tests at the cellular level. In this study, we evaluate the immune efficacy of Padma Hepaten administered intraperitoneally (i.p.) and/or orally in a mice model of hepatic fibrosis. Hepatic fibrosis was induced by 6 weeks of biweekly i.p. carbon tetrachloride (CCl4) injections in male C57Bl6 mice. There were four groups, including naive mice, non-treated fibrotic mice and fibrotic mice treated by Padma Hepaten at weeks 5-6 of fibrosis induction either orally or by i.p. injections. Padma Hepaten was prepared at 10 mg/ml in saline and 250 microl (2.5 mg) were administered four times per week. After week 6, animals were killed. To isolate a Padma Hepaten-associated effect on lymphocytes, splenocytes were harvested from either naive or Padma Hepaten-treated non-fibrotic donors. Isolated splenocytes were therefore reconstituted into two groups of irradiated recipients. Recipients were then administered the same CCl4 regimen. Hepatic fibrosis was determined by sirius red staining of liver sections and by assessment of alpha smooth muscle actin expression compared with beta-actin (both by mRNA as well as the protein liver extract western blotting). Hepatic fibrosis and alanine aminotransferase serum levels were decreased significantly in both Padma Hepaten-treated groups compared with the non-treated fibrotic group. Padma Hepaten treatment was associated with attenuation of lymphocyte subsets in both treated groups. Using a chemiluminescence technique to assess total anti-oxidant capacities (TAC), it was found that both the plasmas and livers of mice treated by CCl4 had significantly higher TAC compared with controls. However, the levels of TAC in animals treated either by CCl4 alone or CCl4 with Padma Hepaten were similar. Adoptive transfer of Padma Hepaten-treated lymphocytes was associated with fibrosis amelioration compared with recipients with naive lymphocytes. CCl4 generates higher levels of anti-oxidant capacities, probably as a response to oxidative stress. Padma Hepaten administration attenuated hepatic fibrogenesis significantly, accompanied by attenuation of lymphocyte but not anti-oxidant capacities.


Subject(s)
Liver Cirrhosis/immunology , Liver Cirrhosis/therapy , Liver/immunology , Natural Killer T-Cells/immunology , Phytotherapy/methods , Plant Extracts/administration & dosage , Actins/analysis , Actins/genetics , Adoptive Transfer , Animals , Biomarkers/analysis , Blotting, Western , Carbon Tetrachloride , Flow Cytometry/methods , Liver/chemistry , Liver/pathology , Liver Cirrhosis/pathology , Lymphocytes/immunology , Male , Mice , Mice, Inbred C57BL , Models, Animal , Whole-Body Irradiation
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