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Reduced Bone Density Based on Hounsfield Units After Long-Segment Spinal Fusion with Harrington Rods. World Neurosurg 2024; 185:e509-e515. [PMID: 38373686 DOI: 10.1016/j.wneu.2024.02.063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/10/2024] [Accepted: 02/12/2024] [Indexed: 02/21/2024]
Abstract
BACKGROUND Long-segment instrumentation, such as Harrington rods, offloads vertebrae within the construct, which may result in significant stress shielding of the fused segments. The present study aimed to determine the effects of spinal fusion on bone density by measuring Hounsfield units (HUs) throughout the spine in patients with a history of Harrington rod fusion. METHODS Patients with a history of Harrington rod fusion treated at a single academic institution were identified. Mean HUs were calculated at 5 spinal segments for each patient: cranial adjacent mobile segment, cranial fused segment, midconstruct fused segment, caudal fused segment, and caudal adjacent mobile segment. Mean HUs for each level were compared using a paired-sample t test, with statistical significance defined by P < 0.05. Hierarchic multiple regression, including age, gender, body mass index, and time since original fusion, was used to determine predictors of midfused segment HUs. RESULTS One hundred patients were included (mean age, 55 ± 12 years; 62% female). Mean HUs for the midconstruct fused segment (110; 95% confidence interval [CI], 100-121) were significantly lower than both the cranial and caudal fused segments (150 and 118, respectively; both P < 0.05), as well as both the cranial and caudal adjacent mobile segments (210 and 130, respectively; both P < 0.001). Multivariable regression showed midconstruct HUs were predicted only by patient age (-2.6 HU/year; 95% CI, -3.4 to -1.9; P < 0.001) and time since original surgery (-1.4 HU/year; 95% CI, -2.6 to -0.2; P = 0.02). CONCLUSIONS HUs were significantly decreased in the middle of previous long-segment fusion constructs, suggesting that multilevel fusion constructs lead to vertebral bone density loss within the construct, potentially from stress shielding.
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Injectable bioactive poly(propylene fumarate) and polycaprolactone based click chemistry bone cement for spinal fusion in rabbits. J Biomed Mater Res A 2024. [PMID: 38644548 DOI: 10.1002/jbm.a.37725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 04/02/2024] [Accepted: 04/04/2024] [Indexed: 04/23/2024]
Abstract
Degenerative spinal pathology is a widespread medical issue, and spine fusion surgeries are frequently performed. In this study, we fabricated an injectable bioactive click chemistry polymer cement for use in spinal fusion and bone regrowth. Taking advantages of the bioorthogonal click reaction, this cement can be crosslinked by itself eliminating the addition of a toxic initiator or catalyst, nor any external energy sources like UV light or heat. Furthermore, nano-hydroxyapatite (nHA) and microspheres carrying recombinant human bone morphogenetic protein-2 (rhBMP-2) and recombinant human vascular endothelial growth factor (rhVEGF) were used to make the cement bioactive for vascular induction and osteointegration. After implantation into a rabbit posterolateral spinal fusion (PLF) model, the cement showed excellent induction of new bone formation and bridging bone, achieving results comparable to autograft control. This is largely due to the osteogenic properties of nano-hydroxyapatite (nHA) and the released rhBMP-2 and rhVEGF growth factors. Since the availability of autograft sources is limited in clinical settings, this injectable bioactive click chemistry cement may be a promising alternative for spine fusion applications in addressing various spinal conditions.
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Bioactive Moldable Click Chemistry Polymer Cement with Nano-Hydroxyapatite and Growth Factor-Enhanced Posterolateral Spinal Fusion in a Rabbit Model. ACS APPLIED BIO MATERIALS 2024; 7:2450-2459. [PMID: 38500414 DOI: 10.1021/acsabm.4c00073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
Spinal injuries or diseases necessitate effective fusion solutions, and common clinical approaches involve autografts, allografts, and various bone matrix products, each with limitations. To address these challenges, we developed an innovative moldable click chemistry polymer cement that can be shaped by hand and self-cross-linked in situ for spinal fusion. This self-cross-linking cement, enabled by the bioorthogonal click reaction, excludes the need for toxic initiators or external energy sources. The bioactivity of the cement was promoted by incorporating nanohydroxyapatite and microspheres loaded with recombinant human bone morphogenetic protein-2 and vascular endothelial growth factor, fostering vascular induction and osteointegration. The release kinetics of growth factors, mechanical properties of the cement, and the ability of the scaffold to support in vitro cell proliferation and differentiation were evaluated. In a rabbit posterolateral spinal fusion model, the moldable cement exhibited remarkable induction of bone regeneration and effective bridging of spine vertebral bodies. This bioactive moldable click polymer cement therefore presents a promising biomaterial for spinal fusion augmentation, offering advantages in safety, ease of application, and enhanced bone regrowth.
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Ventriculoperitoneal Shunt Placement Safety in Idiopathic Normal Pressure Hydrocephalus: Anticoagulated Versus Non-Anticoagulated Patients. World Neurosurg 2024:S1878-8750(24)00581-3. [PMID: 38604534 DOI: 10.1016/j.wneu.2024.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 04/02/2024] [Accepted: 04/03/2024] [Indexed: 04/13/2024]
Abstract
BACKGROUND Many patients with idiopathic normal pressure hydrocephalus (iNPH) have medical comorbidities requiring anticoagulation that could negatively impact outcomes. This study evaluated the safety of ventriculoperitoneal shunt placement in iNPH patients on systemic anticoagulation versus those not on anticoagulation. METHODS Patients >60 years of age with iNPH who underwent shunting between 2018 and 2022 were retrospectively reviewed. Baseline demographics, comorbidities (quantified by modified frailty index and Charlson comorbidity index), anticoagulant/antiplatelet agent use (other than aspirin), operative details, and complications were collected. Outcomes of interest were the occurrence of postoperative hemorrhage and overdrainage. RESULTS A total of 234 patients were included in the study (mean age 75.22 ± 6.04 years; 66.7% male); 36 were on anticoagulation/antiplatelet therapy (excluding aspirin). This included 6 on Warfarin, 19 on direct Xa inhibitors, 10 on Clopidogrel, and 1 on both Clopidogrel and Warfarin. Notably, 70% of patients (164/234) used aspirin alone or combined with anticoagulation or clopidogrel. Baseline modified frailty index was similar between groups, but those on anticoagulant/antiplatelet therapy had a higher mean Charlson comorbidity index (2.67 ± 1.87 vs. 1.75 ± 1.84; P = 0.001). Patients on anticoagulants were more likely to experience tract hemorrhage (11.1 vs. 2.5%; P = 0.03), with no significant difference in the rates of intraventricular hemorrhage or overdrainage-related subdural fluid collection. CONCLUSIONS Anticoagulant and antiplatelet agents are common in the iNPH population, and patients on these agents experienced higher rates of tract hemorrhage following ventriculoperitoneal shunt placement; however, overall hemorrhagic complication rates were similar.
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Bone Quality as Measured by Hounsfield Units More Accurately Predicts Proximal Junctional Kyphosis than Vertebral Bone Quality Following Long-Segment Thoracolumbar Fusion. World Neurosurg 2024:S1878-8750(24)00565-5. [PMID: 38588791 DOI: 10.1016/j.wneu.2024.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 03/31/2024] [Accepted: 04/01/2024] [Indexed: 04/10/2024]
Abstract
OBJECTIVE To compare the prognostic power of Hounsfield units (HU) and Vertebral Bone Quality (VBQ) score for predicting proximal junctional kyphosis (PJK) following long-segment thoracolumbar fusion to the upper thoracic spine (T1-T6). METHODS Vertebral bone quality around the upper instrumented vertebrae (UIV) was measured using HU on preoperative CT and VBQ on preoperative MRI. Spinopelvic parameters were also categorized according to the Scoliosis Research Society-Schwab classification. Univariable analysis to identify predictors of the occurrence of PJK and survival analyses with Kaplan-Meier method and Cox regression were performed to identify predictors of time to PJK (defined as ≥10° change in Cobb angle of UIV+2 and UIV). Sensitivity analyses showed thresholds of HU < 164 and VBQ > 2.7 to be most predictive for PJK. RESULTS Seventy-six patients (mean age 66.0 ± 7.0 years; 27.6% male) were identified, of whom 15 suffered PJK. Significant predictors of PJK were high postoperative pelvic tilt (P = 0.038), high postoperative T1-pelvic angle (P = 0.041), and high postoperative PI-LL mismatch (P = 0.028). On survival analyses, bone quality, as assessed by the average HU of the UIV and UIV+1 was the only significant predictor of time to PJK (odds ratio [OR] 3.053; 95% CI 1.032-9.032; P = 0.044). VBQ measured using the UIV, UIV+1, UIV+2, and UIV-1 vertebrae approached, but did not reach significance (OR 2.913; 95% CI 0.797-10.646; P = 0.106). CONCLUSIONS In larger cohorts, VBQ may prove to be a significant predictor of PJK following long-segment thoracolumbar fusion. However, Hounsfield units on CT have greater predictive power, suggesting preoperative workup for long-segment thoracolumbar fusion benefits from computed tomography versus magnetic resonance imaging alone to identify those at increased risk of PJK.
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Biodegradable poly(caprolactone fumarate) 3D printed scaffolds for segmental bone defects within the Masquelet technique. J Orthop Res 2024. [PMID: 38522018 DOI: 10.1002/jor.25839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/21/2024] [Accepted: 03/08/2024] [Indexed: 03/25/2024]
Abstract
Segmental bone defects, often clinically treated with nondegradable poly(methylmethacrylate) (PMMA) in multistage surgeries, present a significant clinical challenge. Our study investigated the efficacy of 3D printed biodegradable polycaprolactone fumarate (PCLF)/PCL spacers in a one-stage surgical intervention for these defects, focusing on early bone regeneration influenced by spacer porosities. We compared nonporous PCLF/PCL and PMMA spacers, conventionally molded into cylinders, with porous PCLF/PCL spacers, 3D printed to structurally mimic segmental defects in rat femurs for a 4-week implantation study. Histological analysis, including tissue staining and immunohistochemistry with bone-specific antibodies, was conducted for histomorphometry evaluation. The PCLF/PCL spacers demonstrated compressive properties within 6 ± 0.5 MPa (strength) and 140 ± 15 MPa (modulus). Both porous PCLF/PCL and Nonporous PMMA formed collagen-rich membranes (PCLF/PCL: 92% ± 1.3%, PMMA: 86% ± 1.5%) similar to those induced in the Masquelet technique, indicating PCLF/PCL's potential for one-stage healing. Immunohistochemistry confirmed biomarkers for tissue regeneration, underscoring PCLF/PCL's regenerative capabilities. This research highlights PCLF/PCL scaffolds' ability to induce membrane formation in critical-sized segmental bone defects, supporting their use in one-stage surgery. Both solid and porous PCLF/PCL spacers showed adequate compressive properties, with the porous variants exhibiting BMP-2 expression and woven bone formation, akin to clinical standard PMMA. Notably, the early ossification of the membrane into the pores of porous scaffolds suggests potential for bone interlocking and regeneration, potentially eliminating the need for a second surgery required for PMMA spacers. The biocompatibility and biodegradability of PCLF/PCL make them promising alternatives for treating critical bone defects, especially in vulnerable patient groups.
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Significant Reduction in Bone Density as Measured by Hounsfield Units in Patients with Ankylosing Spondylitis or Diffuse Idiopathic Skeletal Hyperostosis. J Clin Med 2024; 13:1430. [PMID: 38592686 PMCID: PMC10932308 DOI: 10.3390/jcm13051430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/05/2024] [Accepted: 02/27/2024] [Indexed: 04/10/2024] Open
Abstract
Background: Multisegmental pathologic autofusion occurs in patients with ankylosing spondylitis (AS) and diffuse idiopathic skeletal hyperostosis (DISH). It may lead to reduced vertebral bone density due to stress shielding. Methods: This study aimed to determine the effects of autofusion on bone density by measuring Hounsfield units (HU) in the mobile and immobile spinal segments of patients with AS and DISH treated at a tertiary care center. The mean HU was calculated for five distinct regions-cranial adjacent mobile segment, cranial fused segment, mid-construct fused segment, caudal fused segment, and caudal adjacent mobile segment. Means for each region were compared using paired-sample t-tests. Multivariable regression was used to determine independent predictors of mid-fused segment HUs. Results: One hundred patients were included (mean age 76 ± 11 years, 74% male). The mean HU for the mid-construct fused segment (100, 95% CI [86, 113]) was significantly lower than both cranial and caudal fused segments (174 and 108, respectively; both p < 0.001), and cranial and caudal adjacent mobile segments (195 and 115, respectively; both p < 0.001). Multivariable regression showed the mid-construct HUs were predicted by history of smoking (-30 HU, p = 0.009). Conclusions: HUs were significantly reduced in the middle of long-segment autofusion, which was consistent with stress shielding. Such shielding may contribute to the diminution of vertebral bone integrity in AS/DISH patients and potentially increased fracture risk.
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P163 Fronto-parietal effective connectivity revealed via TMS is associated with global cognitive functioning. Clin Neurophysiol 2020. [DOI: 10.1016/j.clinph.2019.12.274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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P66 Cortical Fingerprinting using Spatial-Temporal Evolution of TMS evoked EEG responses. Clin Neurophysiol 2020. [DOI: 10.1016/j.clinph.2019.12.177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Intracortical inhibition of the parietal cortex is associated with cognitive function in older adults: A TMS-EEG study. Brain Stimul 2019. [DOI: 10.1016/j.brs.2018.12.483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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EEG functional connectivity predicts causal brain interactions. Brain Stimul 2019. [DOI: 10.1016/j.brs.2018.12.458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Challenges in surgical management of peri-hilar cholangiocarcinoma: a case series on 9-year experience. Eur J Surg Oncol 2019. [DOI: 10.1016/j.ejso.2018.10.253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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DELIRIUM ASSOCIATED WITH ACCELERATED COGNITIVE DECLINE: COMPLICATED DELIRIUM. Innov Aging 2017. [DOI: 10.1093/geroni/igx004.4862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Interpretation of Post-operative Distal Humerus Radiographs After Internal Fixation: Prediction of Later Loss of Fixation. J Hand Surg Am 2016; 41:e337-e341. [PMID: 27522299 DOI: 10.1016/j.jhsa.2016.07.094] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 04/17/2016] [Accepted: 07/13/2016] [Indexed: 02/02/2023]
Abstract
PURPOSE Stable fixation of distal humerus fracture fragments is necessary for adequate healing and maintenance of reduction. The purpose of this study was to measure the reliability and accuracy of interpretation of postoperative radiographs to predict which implants will loosen or break after operative treatment of bicolumnar distal humerus fractures. We also addressed agreement among surgeons regarding which fracture fixation will loosen or break and the influence of years in independent practice, location of practice, and so forth. METHODS A total of 232 orthopedic residents and surgeons from around the world evaluated 24 anteroposterior and lateral radiographs of distal humerus fractures on a Web-based platform to predict which implants would loosen or break. Agreement among observers was measured using the multi-rater kappa measure. RESULTS The sensitivity of prediction of failure of fixation of distal humerus fracture on radiographs was 63%, specificity was 53%, positive predictive value was 36%, the negative predictive value was 78%, and accuracy was 56%. There was fair interobserver agreement (κ = 0.27) regarding predictions of failure of fixation of distal humerus fracture on radiographs. Interobserver variability did not change when assessed for the various subgroups. CONCLUSIONS When experienced and skilled surgeons perform fixation of type C distal humerus fracture, the immediate postoperative radiograph is not predictive of fixation failure. Reoperation based on the probability of failure might not be advisable. TYPE OF STUDY/LEVEL OF EVIDENCE Diagnostic III.
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Phytoremediation potential of moso bamboo (Phyllostachys pubescens) for zinc and ultrastructure changes under zinc toxicity. RUSS J ECOL+ 2015. [DOI: 10.1134/s1067413615050070] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Efficacy of tDCS for Treating Working Memory Dysfunction and Depression in Patients with Temporal Lobe Epilepsy. Brain Stimul 2014. [DOI: 10.1016/j.brs.2014.01.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Clinico-haemato-biochemical changes due to the induced acute toxicity of chlorpyrifos in rabbits ( Oryctolagus Cuniculus). APPLIED BIOLOGICAL RESEARCH 2014. [DOI: 10.5958/0974-4517.2014.00019.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Inferior paralabral ganglion cyst of the shoulder with labral tear -- a rare cause of shoulder pain. Orthop Traumatol Surg Res 2012; 98:193-8. [PMID: 22386705 DOI: 10.1016/j.otsr.2011.09.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2010] [Revised: 09/18/2011] [Accepted: 09/26/2011] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Paralabral ganglion cysts of the shoulder are rare, and their pathogenesis is similar to that of meniscal cysts. The paralabral cysts are most frequently reported along the posterior, superior, and anterior aspects of the glenohumeral joint and are uncommon inferiorly to the joint. These cysts rarely become evident clinically, unless they cause compression of surrounding structures, i.e. nerve. PATIENTS AND METHODS We report a retrospective series of five patients with inferior paralabral ganglion cysts of the shoulder without compression of the surrounding nerve which were treated during the period from March 2007 to December 2009. All these patients presented with only chronic shoulder pain as their chief complaint, and preoperative MRI showed the cyst over the inferior aspect of a torn glenoid labrum. All patients were treated by arthroscopic cystic decompression with labrum repair. All patients were re-evaluated with MRI performed at an average of 15 months postoperatively. The clinical outcome, including the Constant score, was assessed for all patients at a median of 16 months postoperatively. RESULTS All the five patients had remission of pain and were satisfied with the shoulder function. The postoperative MRI in all patients showed no labral cyst recurrence. The median Constant score improved from a preoperative level of 81.5 points to 98.0 points at last follow-up. CONCLUSION This study demonstrates that, in the absence of any nerve compression symptoms around the shoulder joint, inferior paralabral cysts with labral tear also be considered in the differential diagnosis of chronic shoulder pain. Arthroscopic repair of the cyst with repair of the labrum can lead to the disappearance of symptoms. Knowledge of this clinical condition and its imaging features is critical for a correct diagnosis of this uncommon cause of chronic shoulder pain. LEVEL OF EVIDENCE Level IV. Retrospective therapeutic study.
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Abstract
Recently published Department of Health (DoH) guidelines and National Health Service Cervical Screening Programme guidelines recommend referral to a genitourinary (GU) medicine or sexual health clinic as part of the management pathway for young women with post-coital bleeding (PCB). The objectives of this questionnaire study were to ascertain whether GU medicine practitioners agreed with these recommendations and to assess which skills were considered necessary regarding the diagnosis and management of cervical pathology in departments of GU medicine and sexual health and also, therefore, in training in the specialty. The majority of respondents considered it important to check for cervical infection in determining the cause of PCB, but few GU medicine practitioners now perform colposcopy and many consider themselves insufficiently trained to assess the cervix in more detail. Since the colposcope is the optimal tool for examining the anogenital tract, we suggest that colposcopy, in its broadest sense, should be reconsidered as an essential part of GU medicine training.
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Deep-level Transient Spectroscopy of GaAs/AlGaAs Multi-Quantum Wells Grown on (100) and (311)B GaAs Substrates. NANOSCALE RESEARCH LETTERS 2010; 5:1948-1951. [PMID: 21170404 PMCID: PMC2991218 DOI: 10.1007/s11671-010-9820-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 10/19/2010] [Indexed: 05/30/2023]
Abstract
Si-doped GaAs/AlGaAs multi-quantum wells structures grown by molecular beam epitaxy on (100) and (311)B GaAs substrates have been studied by using conventional deep-level transient spectroscopy (DLTS) and high-resolution Laplace DLTS techniques. One dominant electron-emitting level is observed in the quantum wells structure grown on (100) plane whose activation energy varies from 0.47 to 1.3 eV as junction electric field varies from zero field (edge of the depletion region) to 4.7 × 10(6) V/m. Two defect states with activation energies of 0.24 and 0.80 eV are detected in the structures grown on (311)B plane. The E(c)-0.24 eV trap shows that its capture cross-section is strongly temperature dependent, whilst the other two traps show no such dependence. The value of the capture barrier energy of the trap at E(c)-0.24 eV is 0.39 eV.
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Is close follow up feasible for high-risk cervical premalignant lesion in developing countries? BJOG 2009. [DOI: 10.1111/j.1471-0528.2008.02019.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Effect of margin status on cervical intraepithelial neoplasia recurrence following LLETZ in women over 50 years. BJOG 2008; 115:1238-42. [DOI: 10.1111/j.1471-0528.2008.01853.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Variability in neuronal activity in primate cortex during working memory tasks. Neuroscience 2007; 146:1082-108. [PMID: 17418956 DOI: 10.1016/j.neuroscience.2006.12.072] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2004] [Revised: 11/22/2006] [Accepted: 12/24/2006] [Indexed: 11/22/2022]
Abstract
Persistent elevated neuronal activity has been identified as the neuronal correlate of working memory. It is generally assumed in the literature and in computational and theoretical models of working memory that memory-cell activity is stable and replicable; however, this assumption may be an artifact of the averaging of data collected across trials, and needs experimental verification. In this study, we introduce a classification scheme to characterize the firing frequency trends of cells recorded from the cortex of monkeys during performance of working memory tasks. We examine the frequency statistics and variability of firing during baseline and memory periods. We also study the behavior of cells on individual trials and across trials, and explore the stability of cellular firing during the memory period. We find that cells from different firing-trend classes possess markedly different statistics. We also find that individual cells show substantial variability in their firing behavior across trials, and that firing frequency also varies markedly over the course of a single trial. Finally, the average frequency distribution is wider, the magnitude of the frequency increases from baseline to memory smaller, and the magnitude of frequency decreases larger than is generally assumed. These results may serve as a guide in the evaluation of current theories of the cortical mechanisms of working memory.
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Common paediatric orthopaedic problems in the upper limb. Singapore Med J 2006; 47:654-59; quiz 660. [PMID: 16865203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
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Hip to heel approach in the growing years. Singapore Med J 2006; 47:335-8; quiz 339. [PMID: 16572250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
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Abstract
Abstract Cells in the somatosensory cortex of the monkey are known to exhibit sustained elevations of firing frequency during the short-term mnemonic retention of tactile information in a haptic delay task. In this study, we examine the possibility that those firing elevations are accompanied by changes in firing pattern. Patterns are identified by the application of a pattern-searching algorithm to the interspike intervals of spike trains. By sequential use of sets of pattern templates with a range of temporal resolutions, we find patterned activity in the majority of the cells investigated. In general, the degree of patterning significantly increases during active memory. Surrogate analysis suggests that the observed patterns may not be simple linear stochastic functions of instantaneous or average firing frequency. Therefore, during the active retention of a memorandum, the activity of a 'memory cell' may be characterized not only by changes in frequency but also by changes in pattern.
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Abstract
The 'on-call' system for doctors within the health service maintains a continuity of care. However, allowing doctors to drive home after a night on call may pose a public hazard. The aim of this survey was to assess doctors' opinions regarding the safety of driving without adequate sleep.
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Extensive verrucous epidermal naevus. J Eur Acad Dermatol Venereol 2001; 15:269-70. [PMID: 11683300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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Abstract
A 26-year-old Libyan woman presented with asymptomatic nodulo-ulcerative skin lesions present for 1 year. Three years prior to presentation, she had experienced a nasal discharge followed by the development of a nodule in the nasal cavity and a plaque on the hard palate. These lesions had gradually increased in size and ulcerated, resulting in perforation of the nasal septum and palate. Two years later, the patient noticed the appearance of skin lesions: a nodule on the right thumb and numerous nodulo-ulcerative lesions on the extremities. General physical examination was normal with no significant lymphadenopathy. Examination of the oral cavity revealed perforation of the distal nasal septum, with a perforated nodular plaque involving the entire palate, associated with subluxation of the upper incisors (Fig. 1a). On skin examination, multiple firm nodules and nodulo-ulcerative lesions with a central eschar and raised margins were observed. The lesions ranged in size from 0.5 to 5 cm and were distributed on the right hand and fingers, left upper arm (Fig. 1b), left calf, and right thigh. Routine laboratory investigations (liver function tests, serum calcium, electrolytes, lipid profile, urine and stool culture studies) were normal. Immunoelectrophoresis disclosed normal levels of immunoglobulins IgG, IgA, and IgM. Serologic studies for human immunodeficiency virus (HIV) and syphilis, and a tuberculin test, were all negative. A Giemsa-stained tissue smear was negative for Leishmania tropica organisms. Radiological studies disclosed a slight haziness of the maxillary sinuses with perforation of the nasal septum. A chest X-ray was normal. Histopathologic examination of biopsies taken from both the palate and from ulcerated and nonulcerated skin lesions was performed, and all showed similar findings. The biopsy of a nonulcerated skin lesion showed pseudoepitheliomatous epidermal hyperplasia with neutrophilic microabscesses (Fig. 2a). A dermal diffuse and nodular granulomatous mixed infiltrate of lymphocytes, histiocytes, giant cells, numerous eosinophils, and neutrophilic microabscesses was seen in all tissues examined. Septate hyphae were present both within giant cells and free in the dermis (Fig. 2b). The hyphae were branching at a 45 degrees angle and were positive on periodic acid-Schiff and Grocott methenamine silver stains (Fig. 2c). Fungal culture studies of material taken from an ulcerated skin lesion grew Aspergillus flavus. Blood cultures were negative for Aspergillus sp. or other microorganisms. The patient was treated with intravenous amphotericin B, but the medication was discontinued due to her intolerance to the drug. She was subsequently lost to follow-up.
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Abstract
BACKGROUND A preliminary study of 24 cases of xeroderma pigmentosum (XP) was presented in 1990 and later published in 1992. Since then we have seen 18 further cases. OBJECTIVE To study the clinical profile of Libyan cases of XP. METHODS With the help of a special protocol, all 42 cases (23 girls and 19 boys from 29 families) treated and followed between 1981 and 1994 were subjected to detailed analysis. RESULTS A history of consanguinity was present in the parents of 39 patients. XP in Libya is characterized by a relatively high incidence (approximately 15-20 per million of the population), early onset of initial manifestations (median age, 12 months) and malignant tumors (median age, 8 years), severe ocular and oral lesions in a high percentage of patients, and early death (median age, 15.5 years). The malignant skin tumors seen were squamous cell carcinoma (SCC) in 23 patients, basal cell carcinoma (BCC) in 17 patients, and basosquamous carcinoma in two patients. Malignant melanoma was not seen, but lentigo maligna was found in one case. SCC of the tongue, carcinoma of the thyroid, and lymphatic leukemia affected individual patients. Subnormal physical growth was observed in six patients, but none of the patients had significant neurologic abnormalities. The results of etretinate therapy in nine patients revealed that it is an effective preventive agent against carcinogenesis, but not a curative one. CONCLUSIONS Severe ophthalmic manifestations affected a higher percentage of patients at an early age. Malignant melanoma did not develop in any case, except for lentigo maligna in one patient.
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Cutaneous leishmaniasis with unusual presentation. Indian J Dermatol Venereol Leprol 1999; 65:140-142. [PMID: 20921637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Three cases of cutaneous leishmaniasis with unusual presentation seen at Central Hospital Tripoli, Libya are described. Case No. 1 and 2 had 102 and 109 noduloulcerative lesions with generalized almost bilaterally symmetrical distribution, suggestive of dissemination. Case No. 3 had large verrucous carcinoma but histopathology suggested lupoid (chronic cutaneous) leishmaniasis. Patient No. 2 developed hypersensitivity reaction to sodium stibogluconate after 10 days but responded well to the treatment. Case No. 2 did not tolerate the above treatment and was treated successfully with combination of rifampicin and INH. Case No. 3 was treated successfully with liquid nitrogen cryotherapy by Cryosurg-Frigitonics, using special open probes.
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Ossifying fibroma of nasal cavity. J PAK MED ASSOC 1997; 47:312-3. [PMID: 9510646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Fine needle aspiration cytology in parotid lumps. J PAK MED ASSOC 1997; 47:188-90. [PMID: 9301160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Over a period of two years, Fine Needle Aspiration Cytology (FNAC) was performed on 33 patients presenting with a parotid lump. Five patients were excluded as they were treated medically after FNAC report. The FNAC results of 28 cases were compared with histopathological diagnoses of surgically resected specimens. There were 8 true positive, 17 true negative, 1 false positive and 2 false negative cases. Sensitivity was 80%, specificity 94.4% and diagnostic accuracy 89.3%. FNAC is a simple quick, accurate and virtually complications free investigative modality. It is also helpful adjunct to assess preoperatively the suitability and extent of the surgical treatment.
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Intentional non-radical surgery and survival in advanced ovarian cancer: results of a pilot study. Int J Gynecol Cancer 1996. [DOI: 10.1046/j.1525-1438.1996.06060448.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Cowden's disease. Indian J Dermatol Venereol Leprol 1996; 62:322-324. [PMID: 20948105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A 24-year old male patient developed multiple lesions of keratoacanthoma in the epidermal verrucous naevus. He also had multiple papillomatous lesions on the lips, buccal mucosa, gingiva and tongue, with positive family history of similar lesions. He also had multiple skin tags and patchy palmoplantar keratoderma and minimal kyphoscoliosis.
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Generalized granuloma annulare. Indian J Dermatol Venereol Leprol 1995; 61:367-368. [PMID: 20953027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A 35-years-old female patient had generalized pruritic papular lesions, distributed like dermatitis herpetiformis for last 4 years. Histopathologic changes were typical of granuloma annulare with negative results of direct immunofluorescence. The patient did not have association of diabetes mellitus or any other systemic disease. She failed to respond to dapsone therapy and 13-cis-retinoic acid.
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Erythropoietic protoporphyria (Report of three cases). Indian J Dermatol Venereol Leprol 1995; 61:320-322. [PMID: 20953005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Three Libyan patients developing clinical manifestations of erythropoietic protoporphyria (EPP) at 5 years, 7 years and 3 years of age are reported. All of them had variable degree of photosensitivity leading to pitted scarring. Red blood cells in peripheral blood smear revealed positive pink fluorescence in all. First patient responded well with chloroquine therapy and the 3rd patient showed improvement with oral beta-carotene therapy, but the second patient did not show significant response to either.
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Pyoderma gangrenosum in childhood. Indian J Dermatol Venereol Leprol 1995; 61:96-98. [PMID: 20952902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We have treated 4 cases of pyoderma gangrenosum in infancy and childhood in past 2 years. The ages at onset were 6 months, 8 months, 6 months and 11.5 years respectively. Initial lesions were papulopustular in 3 and nodular in 1 patients but later on all of them developed ulcerative lesions with erythematous, violaceous, infiltrated or undermined edges. The lesions were numerous in 3 patients but few in 1 patient. The first patient had very high leucocyte count. In the second patient skin lesions of PG followed measles vaccinations. We could not reveal any association in the other two patients. None of the patient responded to antibiotic therapy. Three patients were treated successfully with dapsone and one with a combination of dapsone and prednisolone. We conclude that pyoderma gangrenosum is not so rare in infancy and it is more likely to occur without associated systemic diseases.
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Cigarette smoking and histological outcome in women with mildly dyskaryotic cervical smears. BRITISH JOURNAL OF OBSTETRICS AND GYNAECOLOGY 1994; 101:49-52. [PMID: 8297868 DOI: 10.1111/j.1471-0528.1994.tb13009.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVE To determine which patient related variables, available at the point of referral, predict the presence of high grade intraepithelial neoplasia when the smear result is mild dyskaryosis with or without co-existent koilocytosis. DESIGN Multivariate analysis of prospective programme trial. SETTING Academic Department Colposcopy clinics at Dudley Road Hospital, Birmingham, UK. SUBJECTS One hundred and sixty-seven women, whose worst ever cervical smear was mild dyskaryosis with or without koilocytosis, referred to colposcopy clinics. All the women had complete data sets, as determined by the format of an ongoing programme, and all were treated by diathermy loop excision of the cervical transformation zone. MAIN OUTCOME MEASURES Age, parity, contraceptive practice, smoking habit, duration of abnormal cytology and the grade of histology in the excised transformation zone. RESULTS Forty-seven out of 78 (60%) smokers, compared with 18 out of 73 (25%) nonsmokers, had high grade disease. The other variables considered in the analysis were not significant or very weakly associated with histological grade when analysed in a univariate analysis. Stepwise logistic regression identified cigarette smoking as a powerful independent predictor of high grade disease. CONCLUSION These data suggest a strong association between smoking and high grade intraepithelial neoplasia in a population of women whose worst ever smear report was mild dyskaryosis. Smoking is a variable that could be built into models to facilitate referral for colposcopic assessment.
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Abstract
A retrospective review of 373 patients with stage I invasive epithelial ovarian cancer was undertaken over a 5 year period to develop a model to characterize the patient at high risk. Actuarial 5-year survival was 70%. To identify factors with an independent effect on 5-year survival, a logistic regression analysis was performed. Adjuvant chemotherapy, histologic grade and peritoneal washings, were identified as independent variables. A model to determine the predictivity of survival was created using a learning sample (2/3 of the cases) and the model was then used to reclassify a validation sample (1/3 of the cases). Using all the independent variables, outcome was predicted correctly in 78% of cases. However the model failed to improve identification of those at risk of recurrence (specificity of 53%).
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