Infarct-related left ventricular diverticulum.
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Coronary Angiography↗
Biomedical subjects
Michael O'Sullivan
Publications and source records attributed to Michael O'Sullivan.
Age effects on diffusion tensor magnetic resonance imaging tractography measures of frontal cortex connections in schizophrenia.
Diffusion tensor magnetic resonance imaging (DT-MRI) has previously been used to investigate white matter tracts in schizophrenia, with inconsistent results. The aim of the study was to use a novel method for tract-specific measurements of fronto-temporal fasciculi in early-onset schizophrenia. We hypothesized that by making tract-specific measurements, clear diffusion abnormalities would be revealed in specific fasciculi in schizophrenia. Measurements of diffusion anisotropy and mean diffusivity were localized within fronto-temporal fasciculi by forming 3-D reconstructions of the cingulum, uncinate, superior longitudinal, and inferior fronto-occipital fasciculi using diffusion tensor tractography. We were limited in our ability to test our hypothesis by the important and surprising finding that age affected DT-MRI-based measures in schizophrenia patients in a different way from comparison subjects, most notably in the left superior longitudinal fasciculus. The youngest schizophrenia patients that we studied had lower diffusion anisotropy than age-matched comparison subjects, but this difference diminished with increasing age. The main conclusion of this study was that direct comparisons of absolute DT-MRI-based measures between individuals with schizophrenia and comparison subjects may be problematic and misleading because of underlying age-related differences in brain maturation between groups.
Adult↗
Correlations between MRS and DTI in cerebral small vessel disease.
Cerebral small vessel disease results in lacunar infarcts and cognitive impairment. Diffusion tensor imaging (DTI) demonstrates a reduction in fractional anisotropy and increase in mean diffusivity, which correlates more strongly with cognition than conventional MRI. The underlying pathological basis for these DTI changes is not known. In this study magnetic resonance spectroscopy was used to determine the biochemical basis of these DTI alterations. Twenty-five patients with lacunar stroke and radiological leukoaraiosis were recruited. Chemical shift imaging (CSI) and DTI were performed on a 1.5 T MRI scanner. A region of interest was positioned in the white matter of the centrum semiovale. Multivoxel CSI data were processed and the metabolite ratios estimated. DTI parameters corresponding to the exact region of tissue excited by CSI were obtained. Mean spectroscopy data and DTI values for each subject were correlated. Univariate analysis revealed a positive correlation between N-acetyl aspartate-creatine (NAA/Cr) and fractional anisotropy (r = 0.52, p = 0.008), and a negative correlation with mean diffusivity (r = -0.51, p = 0.009). Results remained little changed after controlling for mean percentage lesion and mean percentage white matter per voxel (with fractional anisotropy r = 0.54, p = 0.008, and with mean diffusivity r = -0.52, p = 0.01). These findings are consistent with axonal loss or dysfunction, or both, accounting for at least part of the DTI abnormalities found in patients with small vessel disease. It provides evidence that DTI identifies axonal disruption in white matter tracts.
Aged↗
Fabrication of a duplicate denture using visible light-polymerized resin as an interim denture base.
This article describes a technique for producing a duplicate denture using a visible light-polymerized (VLP) denture base for support prior to processing. A 2-part mold of the original denture was made, and then a sheet of VLP resin was reduced to a thickness of 0.5 mm and adapted to the fitting surface of the mold to create a denture base. The base was polymerized and the remaining features, such as the teeth and polished surfaces of the denture, were reproduced in wax. This technique may be helpful when performing subsequent clinical and laboratory procedures.
Acrylic Resins↗
Multiple dental fractures following tongue barbell placement: a case report.
The number of adolescents and young adults undergoing intra-oral piercing, is increasing worldwide. There have been several case reports documenting oral and systemic complications of this practice. These include damage to the dentition, gingivae, infection, speech impediments and nerve damage. The case presented here draws attention to the possibility of multiple tooth fracture as a result of trauma incurred from a barbell inserted into the tongue.
Adolescent↗
Nurses respond to healthcare restructuring: the transformation of the Massachusetts Nurses Association.
The most recent period of Massachusetts healthcare system reorganization began in the early 1980s. In part, this has been a response to soaring healthcare costs, countering them with diminished reimbursements. To decrease labor costs and survive in an increasingly competitive and market-driven healthcare environment, hospitals downsized and laid off nursing staff. Patient care and safety has concomitantly suffered. These efforts severely challenged nurses' status. Radicalized rank and file members of the Massachusetts Nurses Association mobilized against the association leadership's weak efforts to protect nurses' social and economic interests and the deteriorating quality of care. They transformed an association whose main focus was supporting nursing's professional image to one which became an activist labor union of professional workers. The history of this often contentious transformation is presented here within the context of these healthcare system changes. The MNA's successes and pending challenges within the Massachusetts healthcare system are also discussed.
Hospital Restructuring↗
A diffusion tensor magnetic resonance imaging study of frontal cortex connections in very-late-onset schizophrenia-like psychosis.
OBJECTIVE: Onset of psychosis after the age of 60 may be associated with structural abnormalities within cerebral white matter. The authors looked within white-matter tracts, which mediate connectivity of the frontal lobes, in psychotic patients for evidence of loss of fiber integrity consistent with degenerative damage. METHODS: Fourteen patients with very-late-onset schizophrenia-like psychosis and an age-matched control group underwent diffusion tensor magnetic resonance imaging. Tract maps were constructed for each subject from the imaging data, and measurements of fractional anisotropy and mean diffusivity were made within the uncinate, superior longitudinal, and inferior occipito-frontal fasciculi, and the cingulum. RESULTS: There were no significant differences in fractional anisotropy, a measure of the ordering of axons within fiber tracts, nor in mean diffusivity, an orientationally-averaged measure of the bulk diffusivity within each voxel, between patients and control subjects. CONCLUSION: The lack of difference in fractional anisotropy and mean diffusivity measures between patients and controls argues against the presence of structural abnormalities within these tracts and the notion that a focal white-matter abnormality within the tracts investigated underpins the onset of psychosis.
Age of Onset↗
Topacheous gout as a rare cause of spinal stenosis in the lumbar region. Case report.
Despite the fact that gout is a common metabolic disorder, because its involvement of the axial skeleton is rare the diagnosis is often delayed, even in patients with long-standing gout who present with neurological deficits. The authors report the case of a woman with a history of extensive gout, emphasizing the clinical, radiological, and pathological features of a lumbar spinal stenosis.
Biopsy↗
Diffusion tensor imaging of thalamus correlates with cognition in CADASIL without dementia.
BACKGROUND: Executive dysfunction is an early feature in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and may progress to a subcortical dementia. The mechanism of cognitive impairment is incompletely understood, and correlations with T2 lesion volumes are not strong. Diffusion tensor imaging (DTI) may provide a better index of white matter tract damage. Previous DTI studies in CADASIL demonstrated abnormalities in normal-appearing white matter, thalamus, and putamen and correlations with the Mini-Mental State Examination (MMSE). OBJECTIVE: S: To determine whether DTI abnormalities could be identified in nondemented patients with CADASIL and whether these correlated particularly strongly with executive function. METHODS: Eighteen CADASIL subjects underwent DTI and cognitive assessment, including tests of several aspects of executive function. DTI was also performed on 12 age-matched control subjects. RESULTS: Mean diffusivity was increased in white matter lesions, normal-appearing white matter, and normal-appearing gray matter (thalamus, putamen, and globus pallidus). A composite score of executive function correlated with diffusivity in both normal-appearing gray matter (r = -0.73, p = 0.002) and white matter (r = -0.68, p = 0.004). The strongest correlation for gray matter was for the thalamus (r = -0.66, p = 0.004); this remained after controlling for age, gender, and T2 lesion volumes. Correlations with MMSE were much weaker, and there was no correlation between T2 lesion volume and the executive function score (r = -0.29, p = 0.27). CONCLUSIONS: Abnormalities of normal-appearing white and deep gray matter are present in nondemented CADASIL patients, and these DTI measurements correlate particularly strongly with executive function.
Adult↗
The pumping of fluid in cementless cups with holes.
Ten patients who were scheduled for revision for pelvic osteolysis were studied. All had bone-ingrown metal-backed cups with holes and polyethylene liners. Pressures were measured in the osteolytic lesion and in the hip joint while applying cyclic forces across the artificial joint. In 4 cases with lesions that were fully contained by bone, loading of the hip produced a pressure wave in the osteolytic lesion. Cyclic forces, such as those that occur in normal gait, can act on the polyethylene liner, the metal shell, and the supporting bone to pump fluid in the retroacetabular osteolytic lesion. This pumping action may contribute to the pathogenesis of osteolysis by the mechanisms of fluid pressure, fluid flow, or the transportation of wear particles.
Adult↗
The hollow maxillary complete denture: a modified technique.
The severely atrophic maxilla poses a clinical challenge for fabrication of a successful complete denture. This article describes a novel method for fabrication of a hollow maxillary complete denture. It incorporates a clear, pressure-formed matrix of the trial denture external contours to facilitate the fabrication of a silicone putty cavity form. This cavity form ensures the appropriate dimensions of both the denture base acrylic resin for structural integrity and the denture base cavity for optimal weight reduction.
Acrylic Resins↗
Outcome after surgery for Maisonneuve fracture of the fibula.
The aim of this study was to assess outcome in patients treated surgically for Maisonneuve fractures and to highlight factors associated with a suboptimal result. The authors present a review of 14 patients with Maisonneuve fractures. The mean age was 35.5 years. The most common injury mechanism was a twist incurred whilst participating in sport. The goal of treatment was the anatomic restoration of the ankle mortice with accurate renewal of fibular length. All patients had one or two suprasyndesmotic screws inserted percutaneously under fluoroscopic guidance. These were successfully removed under local anaesthesia in 13 cases (93%). Patients were reassessed clinically and evaluated both functionally and radiographically. Average follow-up was 25.3 months. Twelve patients (86%) had a satisfactory result. They returned to previous activity levels and had favourable Global Foot and Ankle (mean: 95.57) and Shoe Comfort (mean: 81.66) Raw Scores. Ankle range of motion and radiographs were normal. Two patients had an unsatisfactory result. Surgical intervention is recommended to maintain reduction of the fibula into the notch on the tibia, as shortening results in mandatory lateral talar displacement, predisposing to painful ankle arthrosis. The severity of the initial injury and co-morbid disease may adversely affect outcome.
Adult↗
Quantitative analysis of asbestos burden in a series of individuals with lung cancer and a history of exposure to asbestos.
Asbestos is recognized as a lung carcinogen. In the present study, tissue from 20 individuals who died from lung cancer and who had a history of exposure to asbestos was evaluated for the presence of asbestos bodies and uncoated asbestos fibers. A digestion procedure was used to isolate the particulates from the tissue. The samples were evaluated by light microcopy to quantify the numbers of ferruginous bodies in the tissue. The uncoated fibers (which included all fibers equal to or greater than 0.5 microm) were analyzed by analytical transmission electron microscopy. Seventeen of the 20 cases were positive for ferruginous bodies (which were morphologically consistent with asbestos bodies). Five of these were found to have concentrations within the range used in our laboratory for the general population (<20 ferruginous bodies/g wet tissue). Nineteen of the 20 cases were found to have asbestos fibers in the higher magnification scan (either 16 K or 20 K). Some of the asbestos fibers identified were specific for the types of exposures that were reported. Most individuals in this study were found to have mixed populations of asbestos fibers in the lung tissue. This suggests that when there are exposures to products containing commercial asbestos there are likely exposures to dust containing noncommercial asbestos. A contrast exists in the dust burden within the lung of these individuals as compared to samples from the general population in that occupational or "occupational-like" exposures such as in these cases are often reflected by the presence of longer fibers of asbestos in the tissue.
Adult↗
Quality control analysis of the potential for asbestos contamination during tissue processing in pathology laboratories.
CONTEXT: Various quality assurance procedures are applied in pathology and analytical microscopy laboratories to ensure accurate results. OBJECTIVE: To assess the potential of cross-contamination of tissue with asbestos fibers and asbestos bodies during the fixation and washing process. DESIGN: Lung tissue from 10 patients with potential asbestos-related disease was evaluated. Samples of fixative, water, and lung tissue from each case were evaluated by light and analytical transmission electron microscopy for asbestos bodies and uncoated asbestos fibers. RESULTS: The lung samples tested contained a range of asbestos bodies and uncoated asbestos fibers. One wash water sample contained one asbestos body. No asbestos bodies or uncoated asbestos fibers were found in any other water or fixative samples. CONCLUSIONS: The absence of uncoated asbestos fibers in wash water or fixative samples argues that the fixation process stabilizes asbestos fibers within tissue and the protocol used in this pathology laboratory protects against cross-contamination of tissue. The finding of one asbestos body in one water sample further supports the efficiency of the protective controls used in the testing methods, since this asbestos body was in the external solution that was being discarded before tissue sampling occurred.
Aged↗
Differential cyclin E expression in human in-stent stenosis smooth muscle cells identifies targets for selective anti-restenosis therapy.
OBJECTIVE: Cell cycle inhibitors are promising agents to prevent or treat human coronary in-stent stenosis (ISS). However, their lack of specificity for ISS vascular smooth muscle cells (VSMCs) may inhibit medial VSMC proliferation and suppress vessel healing. METHODS: To identify inhibitor targets that differentially regulate proliferation of ISS vs. medial VSMCs, we examined cell cycle regulation in human VSMCs derived from (A) normal media, (B) ISS sites and (C) primary atherosclerotic plaques (P-VSMCs) using time-lapse videomicroscopy, flow cytometry, immunoblotting and immunohistochemistry. RESULTS: ISS-VSMC proliferation was intermediate between P-VSMCs and medial VSMCs. Compared with medial cells, P-VSMCs expressed increased p16 and p21, reduced p27, reduced cyclins D(1) and E, and reduced pRb phosphorylation. In contrast, ISS-VSMCs expressed high levels of cyclins E and A with pRb hyperphosphorylation, both in vitro and in vivo, associated with increased and chronic cell proliferation in vivo. Roscovitine, a selective CDK2 inhibitor, inhibited VSMC proliferation by both pRb-dependent and independent pathways and more potently in ISS-VSMCs than medial VSMCs. CONCLUSIONS: Human ISS-VSMCs have marked differences in the stable expression of multiple cell cycle regulators, suggesting that ISS-VSMCs derive from P-VSMCs driven to proliferate through cyclin E overexpression. The critical role for cyclin E-CDK2 enables the identification of the first agent that selectively inhibits ISS-VSMC proliferation.
Biomarkers↗
Homocysteine is a risk factor for cerebral small vessel disease, acting via endothelial dysfunction.
Cerebral small vessel disease (SVD) causes focal lacunar infarction and more diffuse ischaemia, referred to as leukoaraiosis. Endothelial dysfunction has been proposed as a causal mechanism in the disease. Homocysteine is toxic to endothelium. We determined whether elevated homocysteine levels and the methylene tetrahydrofolate reductase (MTHFR) C677T polymorphism are risk factors for SVD as a whole, and for two different SVD subtypes: isolated lacunar infarction and ischaemic leukoaraiosis. We also determined whether any association was mediated by endothelial dysfunction, as assessed by circulating endothelial markers. One hundred and seventy-two Caucasian patients with SVD and 172 community controls of similar age and sex were studied. Serum homocysteine measurement and MTHFR genotyping was performed. Levels of intercellular adhesion molecule 1 (ICAM1) and thrombomodulin were measured in a subgroup. Mean homocysteine levels were higher in SVD than controls [14.55 micromol/l [95% confidence interval (CI) 13.78-15.35] versus 12.01 micromol/l (95% CI 11.42-12.64), P < 0.0005]. Homocysteine was a stronger risk factor in those with ischaemic leukoaraiosis [12.92 (95% CI 4.40-37.98), P < 0.0005) per micromol increase in log homocysteine concentration (P < 0.0005)] in comparison with isolated lacunar infarction [4.22 (95% CI 1.29-13.73), P = 0.02] after controlling for both conventional risk factors and age. The MTHFR 677T allele was a risk factor only in the ischaemic leukoaraiosis group [odds ratio (OR) 2.02 (95% CI 1.31-3.1), P = 0.001]. Inclusion of the endothelial markers ICAM1 and thrombomodulin in a logistic regression model resulted in the association between homocysteine and SVD no longer being significant. In conclusion, hyperhomocysteinaemia is an independent risk factor for SVD, particularly ischaemic leukoaraiosis, and this effect may be mediated via endothelial dysfunction. Homocysteine-lowering therapy may be particularly effective in this subgroup.
Aged↗
Efficient, stereoselective synthesis of oxazolo[3,2-a]pyrazin-5-ones: novel bicyclic lactam scaffolds from the bicyclocondensation of 3-aza-1,5-ketoacids and amino alcohols.
[reaction: see text] The bicyclocondensation of 3-aza-1,5-ketoacids and amino alcohols furnished novel oxazolo[3,2-a]pyrazin-5-one scaffolds possessing angular, ring junction substituents in high yield with excellent levels of substrate-based diastereocontrol. Mild oxidation of serinol-derived scaffolds provided access to a new class of constrained dipeptide surrogates. Deprotection of the endocyclic amine contained within these scaffolds allows for further diversification via N-functionalization.
Amino Alcohols↗
The sensitivity of lavage analysis by light and analytical electron microscopy in correlating the types of asbestos from a known exposure setting.
Lavage material was collected from 12 individuals whose work history included working in a cement manufacturing facility. The manufacturing processes of the facility included the use of crocidolite and chrysotile asbestos. Lavage material was prepared via digestion procedure and then analyzed for the presence of ferruginous bodies by light microscopy and for uncoated asbestos fibers by analytical transmission electron microscopy. A comparison was made as to the sensitivity between two analytical methods for linking a past exposure to a specific type of asbestos. The use of analytical transmission electron microscopy for identification of core material in the ferruginous bodies as well as for quantification of the uncoated asbestos fibers increased the sensitivity of the information obtained from lavage samples as necessary for confirming exposure in the past to specific types of asbestos.
Adult↗