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Williams SC, Hafner JM, Morton DJ, Holm AL, Milberger SM, Koss RG, Loeb JM. The adoption of smoke-free hospital campuses in the United States. Tob Control 2009; 18:451-8. [PMID: 19700437 DOI: 10.1136/tc.2009.030494] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND The adoption of a smoke-free hospital campus policy is often a highly publicised local event. National media coverage suggests that the trend towards adopting these policies is growing, and this publicity can frequently lead hospital administrators to consider the adoption of such policies within their own institutions. Little is actually known, however, about the prevalence of these policies or their impact. OBJECTIVES To determine the national prevalence of smoke-free hospital campus policies and the relation between these policies and performance on nationally standardised measures for smoking cessation counselling in US hospitals. METHODS 4494 Joint Commission-accredited hospitals were invited to complete a web-based questionnaire assessing current smoking policies and future plans. Smoking cessation counselling rates were assessed through nationally standardised measures. RESULTS The 1916 hospitals responding to the survey (43%) were statistically similar to non-responders with respect to performance measure rates, smoking policies and demographic characteristics. Approximately 45% of responders reported an existing smoke-free hospital campus policy. With respect to demographics, higher proportions of smoke-free campus policies were reported in non-teaching and non-profit hospitals. Smoke-free campus hospitals were also more likely to provide smoking cessation counselling to patients with acute myocardial infarction, heart failure and pneumonia who smoke (p<0.001). CONCLUSIONS By February 2008, 45% of US hospitals (up from approximately 3% in 1992) had adopted a smoke-free campus policy; another 15% reported actively pursuing the adoption of such a policy. By the end of 2009, it is likely that the majority of US hospitals will have a smoke-free campus.
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Williams SC, Lopez C, Yoong A, McHugo JM. Developing a robust and efficient pathway for the referral and investigation of women with post-menopausal bleeding using a cut-off of < or =4 mm for normal thickness. Br J Radiol 2007; 80:719-23. [PMID: 17928500 DOI: 10.1259/bjr/87219886] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The majority of women with post-menopausal bleeding (PMB) do not have endometrial cancer, and transvaginal ultrasound (TVUS) is accepted as the screening tool of choice to identify those at highest risk of malignancy. A new referral pathway was instigated in 2000, with patients only being referred to a gynaecologist following an abnormal TVUS result. An initial audit revealed a low positive predictive value for TVUS and a low incidence of detected malignancy. The cut-off value for a normal endometrium was increased from 3 mm to 4 mm in line with published data. This re7hyphen;audit evaluated the effectiveness of implemented changes and identified other areas for improvement. Of the 277 women referred during the study period, 193 had an abnormal or unseen endometrium and were subsequently seen by a gynaecologist. For patients without a histological diagnosis, clinical notes were reviewed and the hospital cancer database scrutinized for all endometrial cancers. Despite a 15.4% increase in referrals, only an additional 2.9% were assessed by gynaecologists. 14 cases of malignancy were identified with a mean endometrial thickness (ET) of 15.7 mm. Failed endometrial sampling was more prevalent with a minimally thickened endometrium. 80 patients with abnormal TVUS had no recorded histological diagnosis. Increasing the ET cut-off value has reduced unnecessary investigations in women at low risk of malignancy. No woman discharged back to her GP has been diagnosed with an endometrial malignancy within 1 year of initial referral. An algorithm has been proposed to further improve the investigation of women with PMB following an abnormal TVUS.
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Kumar AJS, Parmar VN, Kolpattil S, Humad S, Williams SC, Harper WM. Significance of hip rotation on measurement of 'Tip Apex Distance' during fixation of extracapsular proximal femoral fractures. Injury 2007; 38:792-6. [PMID: 17296198 DOI: 10.1016/j.injury.2006.12.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Revised: 11/30/2006] [Accepted: 12/04/2006] [Indexed: 02/02/2023]
Abstract
UNLABELLED The Tip Apex Distance (TAD) is defined as the sum of the distance, in millimetres, from the tip of the lag screw to the apex of the femoral head, as measured on an antero-posterior radiograph and lateral radiograph, after correction has been made for magnification. The relationship between the degree of rotation of the hip joint and its implication on measuring TAD during fixation of a proximal femoral fracture was studied. This relationship has not been previously explored in the English literature. This study involved radiographs of a lag screw placed in a synthetic femur specimen taken in neutral and varying degrees of rotation and adduction/abduction. The lag screw was placed anteriorly in the femoral head. Measurements were taken for each radiograph after correction for magnification. RESULTS Statistical analysis between measurements showed statistically significant differences (P<0.05) of TAD in AP and lateral (abduction and adduction) views. A graph to show the relationship between hip rotation and TAD was conducted and demonstrates a linear correlation. CONCLUSION If an anteriorly placed hip screw is not seen to be breaching the articular surface on a view taken in internal rotation, the screw is definitely not in the joint. Beware of a hip screw appearing very close to the joint surface on a view taken in external rotation or abduction as it could be within the joint. The converse may apply to a posteriorly placed screw.
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Brekke C, Williams SC, Price J, Thorsen F, Modo M. Cellular multiparametric MRI of neural stem cell therapy in a rat glioma model. Neuroimage 2007; 37:769-82. [PMID: 17613248 DOI: 10.1016/j.neuroimage.2007.06.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Revised: 05/18/2007] [Accepted: 06/03/2007] [Indexed: 12/29/2022] Open
Abstract
Cellular multiparametric magnetic resonance imaging (MRI) provided an in vivo visualisation of neural stem cells' (NSCs) tropism for gliomas in the rat brain. NSCs were magnetically labelled in vitro with the bimodal gadolinium-based contrast agent, gadolinium rhodamine dextran (GRID), and injected into the contralateral hemisphere to the developing tumour. Contrast-to-noise measurements showed that GRID-labelled cells induced a signal attenuation on both T2-, T2(*)-weighted images, and a modest signal gain on T1-weighted images. Tumour development and progression were longitudinally monitored in vivo by serial MR scanning. Measurements of tumour volume and tumour progression over time in terms of tumour doubling time showed a tendency towards a reduced tumour growth in NSC-treated animals. MR findings of migration and infiltration of tumours by labelled NSCs were corroborated with immunohistopathology, where labelled cells were detected in the corpus callosum at the tumour border and dispersed in the solid tumour tissue. Immunohistopathology also revealed that macrophages invaded the tumour tissue and in some cases engulfed GRID-labelled stem cells. No significant difference in macrophage recruitment between NSC-treated and vehicle-treated animals were detected, indicating that magnetically labelled NSC do not increase macrophage invasion of tumour tissue. Our findings demonstrate that cellular multiparametric MRI provides a valuable tool for in vivo dynamic monitoring of tumour-directed neural stem cell migration as well as therapeutic efficacy.
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Shiner EK, Terentyev D, Bryan A, Sennoune S, Martinez-Zaguilan R, Li G, Gyorke S, Williams SC, Rumbaugh KP. Pseudomonas aeruginosa autoinducer modulates host cell responses through calcium signalling. Cell Microbiol 2006; 8:1601-10. [PMID: 16984415 DOI: 10.1111/j.1462-5822.2006.00734.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The opportunistic pathogen Pseudomonas aeruginosa utilizes a cell density-dependent signalling phenomenon known as quorum sensing (QS) to regulate several virulence factors needed for infection. Acylated homoserine lactones, or autoinducers, are the primary signal molecules that mediate QS in P. aeruginosa. The autoinducer N-3O-dodecanoyl-homoserine lactone (3O-C12) exerts effects on mammalian cells, including upregulation of pro-inflammatory mediators and induction of apoptosis. However, the mechanism(s) by which 3O-C12 affects mammalian cell responses is unknown. Here we report that 3O-C12 induces apoptosis and modulates the expression of immune mediators in murine fibroblasts and human vascular endothelial cells (HUVEC). The effects of 3O-C12 were accompanied by increases in cytosolic calcium levels that were mobilized from intracellular stores in the endoplasmic reticulum (ER). Calcium release was blocked by an inhibitor of phospholipase C, suggesting that release occurred through inositol triphosphate (IP3) receptors in the ER. Apoptosis, but not immunodulatory gene activation, was blocked when 3O-C12-exposed cells were co-incubated with inhibitors of calcium signalling. This study indicates that 3O-C12 can activate at least two independent signal transduction pathways in mammalian cells, one that involves increases in intracellular calcium levels and leads to apoptosis, and a second pathway that results in modulation of the inflammatory response.
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Shyam Kumar AJ, Parmar V, Bankart J, Williams SC, Harper WM. Comparison of accuracy of lag screw placement in cephalocondylic nails and sliding hip screw plate fixation for extracapsular fractures of the neck of femur. INTERNATIONAL ORTHOPAEDICS 2006; 30:320-4. [PMID: 16680437 PMCID: PMC3172768 DOI: 10.1007/s00264-006-0092-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Accepted: 01/30/2006] [Indexed: 11/25/2022]
Abstract
This study compared the accuracy of lag screw placement between extracapsular femoral fractures fixed with sliding hip screw plate systems and those fixed with cephalocondylic nails. It involved 75 retrospective radiographs of fractures fixed with either a cephalocondylic nail (32) or a sliding hip screw plate system (43). Postoperative anteroposterior and lateral radiographs of the hip were scanned using a digital X-ray scanner and measured using computer software. Measurements were conducted by two independent observers, and the radiographs were calibrated to correct for magnification. Accuracy of lag screw placement was determined by "tip apex distance," described by Baumgaertner et al., and by the ratio method described by Parker. The mean tip apex distance was 24.0 mm in sliding hip screw plate systems and 21.1 mm in cephalocondylic nails. This was found to be statistically significant. Lag screw placement through cephalocondylic nails is more accurate and therefore has less chance of cut-out compared with sliding hip screw plate systems. There was no statistically significant difference using Parker's ratio method because this method quantifies the direction of the screw rather than the depth of penetration.
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Heyer EJ, Wilson DA, Sahlein DH, Mocco J, Williams SC, Sciacca R, Rampersad A, Komotar RJ, Zurica J, Benvenisty A, Quest DO, Todd G, Solomon RA, Connolly ES. APOE-epsilon4 predisposes to cognitive dysfunction following uncomplicated carotid endarterectomy. Neurology 2005; 65:1759-63. [PMID: 16207841 PMCID: PMC1524823 DOI: 10.1212/01.wnl.0000184579.23624.6b] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Between 9% and 23% of patients undergoing otherwise uncomplicated carotid endarterectomy (CEA) develop subtle cognitive decline 1 month postoperatively. The APOE-epsilon4 allele has been associated with worse outcome following stroke. OBJECTIVE To investigate the ability of APOE-epsilon4 to predict post-CEA neurocognitive dysfunction. METHODS Seventy-five patients with CEA undergoing elective CEA were prospectively recruited in this nested cohort study and demographic variables were recorded. Patients were evaluated before and 1 month after surgery with a standard battery of five neuropsychological tests. APOE genotyping was performed by restriction fragment length polymorphism analysis in all patients. Neuropsychological deficits were identified by comparing changes (before to 1 month post-operation) in individual performance on the test battery. Logistic regression was performed for APOE-epsilon4 and previously identified risk factors. RESULTS Twelve of 75 (16%) CEA patients possessed the APOE-epsilon4 allele. Eight of 75 (11%) patients experienced neurocognitive dysfunction on postoperative day 30. One month post-CEA, APOE-epsilon4-positive patients were more likely to be cognitively injured (42%) than APOE-epsilon4-negative patients (5%) (p = 0.002). In multivariate analysis, the presence of the APOE-epsilon4 allele increased the risk of neurocognitive dysfunction at 1 month 62-fold (62.28, 3.15 to 1229, p = 0.007). Diabetes (51.42, 1.94 to 1363, p = 0.02), and obesity (24.43, 1.41 to 422.9, p = 0.03) also predisposed to injury. CONCLUSION The APOE-epsilon4 allele is a robust independent predictor of neurocognitive decline 1 month following CEA.
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Acharya MR, Harper WM, Williams SC. Response to: Factors delaying surgical treatment of hip fractures in elderly patients. Ann R Coll Surg Engl 2004; 86:490. [PMID: 16761348 PMCID: PMC1964293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023] Open
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Johnson K, Williams SC, Balogun M, Dhillon MS. Reducing unnecessary skull radiographs in children: a multidisciplinary audit. Clin Radiol 2004; 59:616-20. [PMID: 15208068 DOI: 10.1016/j.crad.2003.11.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2003] [Revised: 11/20/2003] [Accepted: 11/26/2003] [Indexed: 11/18/2022]
Abstract
AIM To review guidelines on the indications for skull radiographs with a view to improving compliance and reducing unnecessary irradiation of children. METHODS Three audits on the indications, compliance and effect on practice of differing sets of guidelines for skull radiographs following paediatric head trauma were performed. After each audit, alterations in clinical practice with modifications of the guidelines were implemented. The effect of these changes on radiological practice and patient care were recorded. Audits were performed for 3 months (February-April) in 1999, 2001 and 2003. RESULTS The number of children with head injuries presenting was unchanged. The number of skull radiographs performed fell from 146 in 1999 to 95 in 2001 and 50 in 2003. Compliance with hospital guidelines increased from 85% in 1999 to 100% in 2003. No neurosurgical problems were missed. CONCLUSION The implementation of guidelines that are acceptable to all specialties will improve compliance and reduce unnecessary radiographs being performed. The involvement of the radiography staff will help maintain compliance. The training of junior staff and maintaining good communication with involved departments will improve patient care.
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Cordell-Smith JA, Williams SC, Harper WM, Gregg PJ. Lower limb arthroplasty complicated by deep venous thrombosis. Prevalence and subjective outcome. THE JOURNAL OF BONE AND JOINT SURGERY. BRITISH VOLUME 2004; 86:99-101. [PMID: 14765874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
The aim of this study was to determine the prevalence of deep venous thrombosis (DVT) following lower limb arthroplasty and to assess whether this adversely affected satisfaction, relief from pain, or the level of mobility as perceived by patients. Six hundred and ten consecutive recipients of primary total hip replacement (THR) or total knee replacement (TKR) underwent routine post-operative venography. The functional outcome had already been assessed at one year by using the Regional Arthroplasty Database questionnaire, the results of which were correlated to venographic records. The combined prevalence of DVT after THR and TKR in the patients, who did not receive chemical thromboprophylaxis, was 46.4%. Thrombus was identified in 57.6% of those with a TKR and in 33.5% of patients with a THR. Proximal thrombus was found in 11.0% of TKRs and in 14.8% of THRs. One year after surgery, patients who had a DVT established by venography did not report higher levels of immobility (p = 0.07), discomfort (p = 0.12) or dissatisfaction (p = 0.23) when compared to those with patent venous systems. This suggests that the prevalence of DVT following TKR/THR without chemical thromboprophylaxis is high and these findings are consistent with the literature. However, patients did not perceive thrombosis to compromise their overall outcome. This challenges the belief that DVT is associated with morbidity and calls for further comprehensive research in this area. The low morbidity of the lower limb associated with DVT in these patients does not support the use of chemical thromboprophylaxis.
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Williams SC, Hollins D, Barden-Marshall S, Harper WM. Improving the quality of patient care: patient satisfaction with a nurse-led fracture clinic service. Ann R Coll Surg Engl 2003; 85:115-6. [PMID: 12648343 PMCID: PMC1963733 DOI: 10.1308/003588403321219902] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A prospective study was conducted to assess nurse-led follow-up of patients with fracture.
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Phillips ML, Medford N, Senior C, Bullmore ET, Suckling J, Brammer MJ, Andrew C, Sierra M, Williams SC, David AS. Depersonalization disorder: thinking without feeling. Psychiatry Res 2001; 108:145-60. [PMID: 11756013 DOI: 10.1016/s0925-4927(01)00119-6] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Patients with depersonalization disorder (DP) experience a detachment from their own senses and surrounding events, as if they were outside observers. A particularly common symptom is emotional detachment from the surroundings. Using functional magnetic resonance imaging (fMRI), we compared neural responses to emotionally salient stimuli in DP patients, and in psychiatric and healthy control subjects. Six patients with DP, 10 with obsessive-compulsive disorder (OCD), and six volunteers were scanned whilst viewing standardized pictures of aversive and neutral scenes, matched for visual complexity. Pictures were then rated for emotional content. Both control groups rated aversive pictures as much more emotive, and demonstrated in response to these scenes significantly greater activation in regions important for disgust perception, the insula and occipito-temporal cortex, than DP patients (covarying for age, years of education and total extent of brain activation). In DP patients, aversive scenes activated the right ventral prefrontal cortex. The insula was activated only by neutral scenes in this group. Our findings indicate that a core phenomenon of depersonalization--absent subjective experience of emotion--is associated with reduced neural responses in emotion-sensitive regions, and increased responses in regions associated with emotion regulation.
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O'Sullivan M, Summers PE, Jones DK, Jarosz JM, Williams SC, Markus HS. Normal-appearing white matter in ischemic leukoaraiosis: a diffusion tensor MRI study. Neurology 2001; 57:2307-10. [PMID: 11756617 DOI: 10.1212/wnl.57.12.2307] [Citation(s) in RCA: 177] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Ischemic leukoaraiosis is a consistent concomitant of vascular dementia. Conventional MRI provides little information about underlying white matter tract disruption and correlates poorly with cognitive dysfunction. Diffusion tensor MRI may provide better markers of tract integrity. Changes in the normal-appearing white matter were demonstrated in 30 patients with ischemic leukoaraiosis compared with 17 age-matched control subjects. These changes correlated with executive dysfunction assessed by the Wisconsin Card Sorting Test.
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Suzuki Y, Critchley HD, Suckling J, Fukuda R, Williams SC, Andrew C, Howard R, Ouldred E, Bryant C, Swift CG, Jackson SH. Functional magnetic resonance imaging of odor identification: the effect of aging. J Gerontol A Biol Sci Med Sci 2001; 56:M756-60. [PMID: 11723149 DOI: 10.1093/gerona/56.12.m756] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Sense of smell declines with age and impairment in olfaction has been observed in some neurodegenerative disorders such as Alzheimer's disease. Functional neuroimaging techniques enable researchers to observe brain regions activated by olfactory stimuli. METHODS We gave three mainly olfactory-mediated odors (limonene, methylsalicylate, and eugenol) to six young and six elderly subjects and observed the areas activated by using blood oxygen level dependent contrast functional magnetic resonance imaging. RESULTS The group mapping of young subjects showed extensive activation in the orbitofrontal cortex, commonly believed to be the olfactory cortex, some limbic areas (the hippocampus and the thalamus), regions involved with gustatory sensation (the anterior insula and the inferior postcentral gyrus), superior and inferior temporal gyri, and cerebellum. In the elderly group, only the left inferior temporal gyrus and the primary visual cortex reached accepted significance levels. CONCLUSIONS We have therefore confirmed previous reports of brain regions involved in olfactory processing in young volunteers and demonstrated decreased activation in elderly volunteers.
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Williams SC, Oehninger S, Gibbons WE, Van Cleave WC, Muasher SJ. Delaying the initiation of progesterone supplementation results in decreased pregnancy rates after in vitro fertilization: a randomized, prospective study. Fertil Steril 2001; 76:1140-3. [PMID: 11730741 DOI: 10.1016/s0015-0282(01)02914-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
OBJECTIVE To compare IVF outcome between two protocols for luteal phase supplementation, one beginning on day 3 after oocyte retrieval and the other beginning on day 6 after retrieval. DESIGN Prospective, randomized study. SETTING University-based assisted reproductive technology center. PATIENT(S) One hundred twenty-six consecutive patients undergoing IVF between January and July 2000. INTERVENTION(S) Patients were randomized to begin luteal phase support using vaginal progesterone beginning either on day 3 after oocyte retrieval or on day 6 after oocyte retrieval. MAIN OUTCOME MEASURE(S) Clinical pregnancy rates and implantation rates. RESULT(S) All patients randomized underwent transfer. There were no differences in age, oocytes retrieved, or embryos transferred between the two groups. Those patients receiving luteal phase support with progesterone beginning on day 6 after retrieval had a significantly lower clinical pregnancy rate per transfer compared with those beginning support on day 3 after retrieval (44.8% vs. 61.0%, respectively). This difference in pregnancy rates was greater in those patients undergoing a luteal gonadotropin releasing hormone (GnRH) agonist down-regulation protocol (47.5% vs. 71.4%, day 6 vs. day 3, respectively). Beginning support on day 6 also significantly decreased implantation rates in the GnRH agonist group (21.0% vs. 34.0%, day 6 vs. day 3, respectively). CONCLUSION(S) Pregnancy rates are significantly decreased by initiating luteal-phase progesterone supplementation on day 6 after oocyte retrieval during in vitro fertilization cycles.
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Steel C, Haworth EJ, Peters E, Hemsley DR, Sharma T, Gray JA, Pickering A, Gregory L, Simmons A, Bullmore ET, Williams SC. Neuroimaging correlates of negative priming. Neuroreport 2001; 12:3619-24. [PMID: 11733723 DOI: 10.1097/00001756-200111160-00049] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Many theoretical accounts of selective attention and memory retrieval include reference to active inhibitory processes, such as those argued to underlie the negative priming effect. fMRI was used in order to investigate the areas of cortical activation associated with Stroop interference, Stroop facilitation and Stroop negative priming tasks. The most significant activation within the negative priming task was within the inferior parietal lobule, left temporal lobe and frontal lobes. Areas of cortical activation are discussed with reference to theoretical accounts of the negative priming effect.
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Ellis CM, Suckling J, Amaro E, Bullmore ET, Simmons A, Williams SC, Leigh PN. Volumetric analysis reveals corticospinal tract degeneration and extramotor involvement in ALS. Neurology 2001; 57:1571-8. [PMID: 11706094 DOI: 10.1212/wnl.57.9.1571] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Pathologic changes in the motor cortex and corticospinal tracts in ALS may be reflected by abnormal signal intensities on conventional MRI. The sensitivity of these changes in detecting underlying pathology remains unclear. METHOD The authors used automated image analysis to quantify volumes of cerebral gray and white matter in 16 patients with ALS (eight limb onset, eight bulbar onset) and eight normal controls. Previously they had demonstrated a reduction in N-acetyl aspartate/creatine + phosphocreatine (NAA/[Cr + PCr]) measured by (1)H-MRS in the subcortical white matter in the motor cortex region in the patients with bulbar-onset ALS. To determine whether this resulted from axonal degeneration, they also compared gray and white matter volumes in the patients with limb- and bulbar-onset ALS. RESULTS There were no differences in the total brain volumes of gray or white matter for the three subject groups (p > 0.23). Comparison of the total ALS group and controls revealed localized deficits in gray matter volume centered on Brodmann areas 8, 9, and 10 bilaterally. Comparison of the patients with limb- and bulbar-onset ALS revealed deficits in the white matter volume in the bulbar-onset group, extending bilaterally from the precentral gyrus into the internal capsule and brainstem, consistent with the course of the corticospinal tract. There was no loss in gray matter volume in the precentral gyri. CONCLUSIONS The loss of gray matter in the frontal regions (total ALS group) provides further support that ALS is a multisystem disorder. In addition, there is in vivo evidence of axonal degeneration in the subcortical white matter in the motor region in patients with bulbar-onset ALS. This is consistent with a "dying back" process affecting cortical motoneurons in bulbar-onset ALS.
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Rossell SL, Bullmore ET, Williams SC, David AS. Brain activation during automatic and controlled processing of semantic relations: a priming experiment using lexical-decision. Neuropsychologia 2001; 39:1167-76. [PMID: 11527554 DOI: 10.1016/s0028-3932(01)00049-5] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Semantic relations may be studied using the experimental technique known as semantic priming, in which a word 'primes' the processing of a related target (e.g. lion-tiger), following a short delay. Priming may be automatic or, with longer delays, under more controlled processing. This study used functional magnetic resonance imaging (fMRI) to examine the cerebral activation during two lexical-decision semantic priming experiments, with a short and long delay, representing automatic and controlled processing, respectively. A further two un-primed lexical-decision tasks were performed to distinguish cerebral activation specific to semantic priming itself from those utilised during lexical-decision processes. Distinct regions of anterior cingulate cortex (ACC) were critical to automatic and controlled semantic priming, whilst the putamen and hippocampal complex responded differently to unrelated and semantically related prime-target pairs. Lexical-decision alone revealed activation in posterior temporal cortex especially on the left, in agreement with previous neuroimaging studies. The results provide a plausible neural substrate for common semantic relations independent of task demands and further emphasise the regional functional specialisation of the ACC.
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Overmeyer S, Bullmore ET, Suckling J, Simmons A, Williams SC, Santosh PJ, Taylor E. Distributed grey and white matter deficits in hyperkinetic disorder: MRI evidence for anatomical abnormality in an attentional network. Psychol Med 2001; 31:1425-1435. [PMID: 11722157 DOI: 10.1017/s0033291701004706] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Previous neuroimaging studies of children with attention deficit hyperactivity disorder (ADHD) have demonstrated anatomic and functional abnormalities predominantly in frontal and striatal grey matter. Here we report the use of novel image analysis methods, which do not require prior selection of regions of interest, to characterize distributed morphological deficits of both grey and white matter associated with ADHD. METHODS Eighteen children with a refined phenotype of ADHD, who also met ICD-10 criteria for hyperkinetic disorder (mean age 10.4 years), and 16 normal children (mean age 10.3 years) were compared using magnetic resonance imaging. The groups were matched for handedness, sex, height, weight and head circumference. Morphological differences between groups were estimated by fitting a linear model at each voxel in standard space, applying a threshold to the resulting voxel statistic maps to generate clusters of spatially contiguous suprathreshold voxels, and testing cluster 'mass', or the sum of suprathreshold voxel statistics in each 2D cluster, by repeated random resampling of the data. RESULTS The hyperkinetic children had significant grey matter deficits in right superior frontal gyrus (Brodmann area (BA) 8/9), right posterior cingulate gyrus (BA 30) and the basal ganglia bilaterally (especially right globus pallidus and putamen). They also demonstrated significant central white matter deficits in the left hemisphere anterior to the pyramidal tracts and superior to the basal ganglia. CONCLUSIONS This pattern of spatially distributed grey matter deficit in the right hemisphere is compatible with the hypothesis that ADHD is associated with disruption of a large scale neurocognitive network for attention. The left hemispheric white matter deficits may be due to dysmyelination.
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Ridler K, Bullmore ET, De Vries PJ, Suckling J, Barker GJ, Meara SJ, Williams SC, Bolton PF. Widespread anatomical abnormalities of grey and white matter structure in tuberous sclerosis. Psychol Med 2001; 31:1437-1446. [PMID: 11722158 DOI: 10.1017/s0033291701004561] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Neuroimaging studies of tuberous sclerosis complex (TSC) have previously focused mainly on tubers or subependymal nodules. Subtle pathological changes in the structure of the brain have not been studied in detail. Computationally intensive techniques for reliable morphometry of brain structure are useful in disorders like TSC, where there is little prior data to guide selection of regions of interest. METHODS Dual-echo, fast spin-echo MRI data were acquired from 10 TSC patients of normal intelligence and eight age-matched controls. Between-group differences in grey matter, white matter and cerebrospinal fluid were estimated at each intracerebral voxel after registration of these images in standard space; a permutation test based on spatial statistics was used for inference. CSF-attenuated FLAIR images were acquired for neuroradiological rating of tuber number. RESULTS Significant deficits were found in patients, relative to comparison subjects, of grey matter volume bilaterally in the medial temporal lobes, posterior cingulate gyrus, thalamus and basal ganglia, and unilaterally in right fronto-parietal cortex (patients -20%). We also found significant and approximately symmetrical deficits of central white matter involving the longitudinal fasciculi and other major intrahemispheric tracts (patients -21%); and a bilateral cerebellar region of relative white matter excess (patients +28%). Within the patient group, grey matter volume in limbic and subcortical regions of deficit was negatively correlated with tuber count. CONCLUSIONS Neuropathological changes associated with TSC may be more extensive than hitherto suspected, involving radiologically normal parenchymal structures as well as tubers, although these two aspects of the disorder may be correlated.
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Shergill SS, Cameron LA, Brammer MJ, Williams SC, Murray RM, McGuire PK. Modality specific neural correlates of auditory and somatic hallucinations. J Neurol Neurosurg Psychiatry 2001; 71:688-90. [PMID: 11606687 PMCID: PMC1737587 DOI: 10.1136/jnnp.71.5.688] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Somatic hallucinations occur in schizophrenia and other psychotic disorders, although auditory hallucinations are more common. Although the neural correlates of auditory hallucinations have been described in several neuroimaging studies, little is known of the pathophysiology of somatic hallucinations. Functional magnetic resonance imaging (fMRI) was used to compare the distribution of brain activity during somatic and auditory verbal hallucinations, occurring at different times in a 36 year old man with schizophrenia. Somatic hallucinations were associated with activation in the primary somatosensory and posterior parietal cortex, areas that normally mediate tactile perception. Auditory hallucinations were associated with activation in the middle and superior temporal cortex, areas involved in processing external speech. Hallucinations in a given modality seem to involve areas that normally process sensory information in that modality.
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Curtis VA, Dixon TA, Morris RG, Bullmore ET, Brammer MJ, Williams SC, Sharma T, Murray RM, McGuire PK. Differential frontal activation in schizophrenia and bipolar illness during verbal fluency. J Affect Disord 2001; 66:111-21. [PMID: 11578663 DOI: 10.1016/s0165-0327(00)00240-8] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
INTRODUCTION The precise nature of frontal lobe dysfunction in schizophrenia remains unclear. We have previously demonstrated, using fMRI, a task-specific attenuation of frontal activation in schizophrenic patients. By using an identical methodology in matched bipolar subjects, we sought to determine whether this finding is specific to schizophrenia or a correlate of psychosis in general. METHOD Five dextral male bipolar patients and matching groups of schizophrenic subjects and controls were studied using fMRI. Echoplanar images were acquired while subjects performed two paced tasks: covert verbal fluency and a semantic decision task. Generic brain activation maps were constructed from individual images by sinusoidal regression analysis. Between-group differences in the mean power of experimental response were identified on a voxel-wise basis by an analysis of variance (ANOVA). RESULTS The bipolar patients showed extensive prefrontal activation during verbal fluency which was significantly greater than in controls. There was no difference in the prefrontal BOLD response during the semantic decision task. CONCLUSIONS These data indicate that bipolar patients show a strikingly different pattern of frontal responses compared to those with schizophrenia and provide further evidence that abnormal frontal activation in psychotic disorders is more apparent during verbal fluency than semantic decision.
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Gregory LJ, O'Neill MJ, Nunn JA, Gray JA, Williams SC. Diffusion-weighted magnetic resonance imaging detects early neuropathology following four vessel occlusion ischemia in the rat. J Magn Reson Imaging 2001; 14:207-14. [PMID: 11536396 DOI: 10.1002/jmri.1175] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Early neuropathology following a prolonged duration of four-vessel occlusion (4 VO) ischemia in the rat was charted using magnetic resonance imaging (MRI). Animals received either 30 minutes of 4 VO (N = 6) or sham operation (N = 6) prior to in vivo assessment. Proton density and T(2) and combined T(2)/diffusion-weighted (T(2)/DW) MRI were performed at 6, 24, and 72 hours postocclusion. T(2)/DW imaging was the most effective sequence for delineating between injured and intact tissues, indicating neuropathology in the dorsolateral striatum at 24 hours and in the CA1/CA2 subfields of the hippocampus at 72 hours following ischemia. Apparent diffusion coefficient values were significantly reduced in the striatum (P = 0.03) and hippocampus (P = 0.005) at 24 and 72 hours, respectively. This is the first report, to our knowledge, of T(2)/DW imaging detecting lesions following 4 VO in accord with the known temporal evolution of ischemic brain damage.
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Williams SC, Alton H. Frontal headaches and an abnormal chest x-ray. Paediatr Respir Rev 2001; 2:276-8. [PMID: 12056409 DOI: 10.1053/prrv.2001.0152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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O'Sullivan M, Jones DK, Summers PE, Morris RG, Williams SC, Markus HS. Evidence for cortical "disconnection" as a mechanism of age-related cognitive decline. Neurology 2001; 57:632-8. [PMID: 11524471 DOI: 10.1212/wnl.57.4.632] [Citation(s) in RCA: 561] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Normal aging is accompanied by a decline of cognitive abilities, and executive skills may be affected selectively, but the underlying mechanisms remain obscure and preventive strategies are lacking. It has been suggested that cortical "disconnection" due to the loss of white matter fibers may play an important role. But, to date, there has been no direct demonstration of structural disconnection in humans in vivo. METHODS The authors used diffusion tensor MRI to look for evidence of ultrastructural changes in cerebral white matter in a group of 20 elderly volunteers with normal conventional MRI scans, and a group of 10 younger controls. The older group also underwent neuropsychological assessment. RESULTS Diffusional anisotropy, a marker of white matter tract integrity, was reduced in the white matter of older subjects and fell linearly with increasing age in the older group. Mean diffusivity was higher in the older group and increased with age. These changes were maximal in anterior white matter. In the older group, anterior mean diffusivity correlated with executive function assessed by the Trail Making Test. CONCLUSIONS These findings provide direct evidence that white matter tract disruption occurs in normal aging and would be consistent with the cortical disconnection hypothesis of age-related cognitive decline. Maximal changes in anterior white matter provide a plausible structural basis for selective loss of executive functions. In addition to providing new information about the biological basis of cognitive abilities, diffusion tensor MRI may be a sensitive tool for assessing interventions aimed at preventing cognitive decline.
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