BACKGROUND—Three different techniques to evaluate endothelium-dependent vasodilation in the peripheral circulation have been described but not simultaneously tested in a large-scale population-based ...setting. This study aimed to evaluate the feasibility and usefulness of these techniques in the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study.
METHODS AND RESULTS—In the population-based PIVUS study (1016 subjects aged 70 years), the invasive forearm technique with acetylcholine given in the brachial artery (EDV), the brachial artery ultrasound technique with measurement of flow-mediated dilatation (FMD), and the pulse wave analysis method with β-2-agonist (terbutaline) provocation were successfully used in 87%, 97%, and 86% of the sample, respectively. The results of EDV and pulse wave analysis were interrelated (r=0.12, P=0.0013), but no relationships were found with FMD measurements. All 3 techniques were correlated to the Framingham risk score (r=0.10 to 0.12, P=0.0007 to 0.001). In multiple regression analysis, however, only EDV and FMD were independently associated with the Framingham score.
CONCLUSIONS—All 3 evaluated techniques were feasible to perform in a general elderly population. Both the invasive forearm technique and FMD were independently associated with increased coronary risk, suggesting that information on conduit artery and resistance artery endothelial function carry different, but important, information in the elderly. If the invasive technique cannot be used, the pulse wave based technique is an alternative.
In recent years there has been a tremendous growth in the use of vibrational spectroscopic methods for diagnosis and screening. These applications range from diagnosis of disease states in humans, ...such as cancer, to rapid identification and screening of microorganisms. The growth in such types of studies has been possible thanks to advances in instrumentation and associated computational and mathematical tools for data processing and analysis. This volume of Advances in Biomedical Spectroscopy contains chapters from leading experts who discuss the latest advances in the application of Fourier transform infrared (FTIR), Near infrared (NIR), Terahertz and Raman spectroscopy for diagnosis and screening in fields ranging from medicine, dentistry, forensics and aquatic science. Many of the chapters provide information on sample preparation, data acquisition and data interpretation that would be particularly valuable for new users of these techniques including established scientists and graduate students in both academia and industry.
This title covers recent advances in a variety of biomedical applications of nanostructured materials, as the field evolves from prototype device to real-world application. It presents the main types ...of nanomaterial used in medical application today: semiconductor nanomaterials, Magnetic nanomaterials, metal nanoparticles, Carbon nanomaterials, Hydrogel nanocomposites, Liposomes, Dendrimers, Polymer nanocomposites, and Biodegradable polymers. Structurally the work is demarcated into the six most popular areas of research: (1) biocompatibility of nanomaterials with living organisms in their various manifestations (2) nanobiosensors for clinical diagnostics, detecting biomolecules which are useful in the clinical diagnosis of genetic, metabolically acquired, induced or infectious disease (3) targeted drug delivery for nanomaterials in their various modifications (4) nanomedical devices and structures which are used in the development of implantable medical devices and structures such as nanorobots (5) nanopharmacology, as novel nanoparticles are increasingly engineered to diagnose conditions and recognize pathogens, identify ideal pharmaceutical agents to treat the condition or pathogens,fuel high-yield production of matched pharmaceuticals (potentially in vivo), locate, attach or enter target tissue, structures or pathogens; and dispense the ideal mass of matched biological compound to the target regions (6) nanotoxicology and remediation, which focuses on finished and on-going various toxicity evaluations on various nanomaterials that are used and currently being developed for medical applications
Discusses the most important biomedical applications and devices of nanomaterials: drug delivery, medical imaging, gene therapy, nanorobots, biosensors and diagnostics Focuses on current commercialized techniques and applications, ensuring the work is entirely relevant to a rapidly evolving fieldReviews the most recent studies on nanomaterial toxicity, thereby responding to the widescale private, policy and public interest in nanoscience
This study evaluates the usefulness of PET for the preoperative evaluation of brain gliomas and methods of quantification of PET results.
Fifty-four patients with brain gliomas were studied by PET ...with 18F-fluorodeoxyglucose (FDG) (n = 45) and/or 11C-methionine (MET) (n = 41) before any treatment. Results of visual analysis, calculation of glucose consumption and five tumor-to-normal brain ratios for both tracers were correlated with two histologic grading systems and with follow-up.
Visual analysis (for FDG) and tumor-to-mean cortical uptake (T/MCU) ratio proved to be the best tools for the evaluation of PET results. Methionine was proven to be better than FDG at delineating low-grade gliomas. Tumor-to-mean cortical uptake ratios for FDG and MET were clearly correlated (r = 0.78), leading to the equation T/MCU(FDG) = 0.4 x T/MCU(MET). We showed a good correlation between FDG PET and histologic grading. MET uptake could not differentiate between low-grade and anaplastic astrocytomas but was significantly increased in glioblastomas. Low-grade oligodendrogliomas exhibited high uptake of FDG and MET, probably depending more on oligodendroglial cellular differentiation than on proliferative potential. Uptake was decreased in anaplastic oligodendrogliomas, probably due to dedifferentiation. Care must be taken with peculiar histologic subgroups, i.e., juvenile pilocytic astrocytomas and oligodendrogliomas, because of a discrepancy between high PET metabolism and low proliferative potential (good prognosis). Both tracers proved useful for the prediction of survival prognosis. Methionine proved slightly superior to FDG for predicting the histologic grade and prognosis of gliomas, despite the impossibility of differentiation between Grades II and III astrocytomas with MET. This superiority of MET could be explained by patient sampling (low number of Grade III gliomas submitted to examination with both tracers). The combination of both tracers improved the overall results compared to each tracer alone.
Both tracers are useful for the prediction of the histologic grade and prognosis. The apparent superiority of MET over FDG could be due to the small number of Grade III gliomas studied with both tracers.
Summary Background The role of exposure to substances in the workplace in new-onset asthma is not well characterised in population-based studies. We therefore aimed to estimate the relative and ...attributable risks of new-onset asthma in relation to occupations, work-related exposures, and inhalation accidents. Methods We studied prospectively 6837 participants from 13 countries who previously took part in the European Community Respiratory Health Survey (1990–95) and did not report respiratory symptoms or a history of asthma at the time of the first study. Asthma was assessed by methacholine challenge test and by questionnaire data on asthma symptoms. Exposures were defined by high-risk occupations, an asthma-specific job exposure matrix with additional expert judgment, and through self-report of acute inhalation events. Relative risks for new onset asthma were calculated with log-binomial models adjusted for age, sex, smoking, and study centre. Findings A significant excess asthma risk was seen after exposure to substances known to cause occupational asthma (Relative risk=1·6, 95% CI 1·1–2·3, p=0·017). Risks were highest for asthma defined by bronchial hyper-reactivity in addition to symptoms (2·4, 1·3–4·6, p=0·008). Of common occupations, a significant excess risk of asthma was seen for nursing (2·2, 1·3–4·0, p=0·007). Asthma risk was also increased in participants who reported an acute symptomatic inhalation event such as fire, mixing cleaning products, or chemical spills (RR=3·3, 95% CI 1·0–11·1, p=0·051). The population-attributable risk for adult asthma due to occupational exposures ranged from 10% to 25%, equivalent to an incidence of new-onset occupational asthma of 250–300 cases per million people per year. Interpretation Occupational exposures account for a substantial proportion of adult asthma incidence. The increased risk of asthma after inhalation accidents suggests that workers who have such accidents should be monitored closely.
6-(18)F-Fluoro-L-dopa (FDOPA) has been widely used as a biomarker for catecholamine synthesis, storage, and metabolism--its intense uptake in the striatum, and fainter uptake in other brain regions, ...is correlated with the symptoms and pathophysiology of Parkinson's disease (PD). 6-(18)Ffluoro-m-tyrosine (FMT), which also targets L-amino acid decarboxylase, has potential advantages over FDOPA as a radiotracer because it does not form catechol-O-methyltransferase (COMT) metabolites. The purpose of the present study was to compare the regional distribution of these radiotracers in the brains of PD patients. Fifteen Parkinson's patients were studied with FMT and FDOPA positron emission tomography (PET) as well as high-resolution structural magnetic resonance imaging (MRI). MRI's were automatically parcellated into neuroanatomical regions of interest (ROIs) in Freesurfer (http://surfer.nmr.mgh.harvard.edu); region-specific uptake rate constants (Kocc) were generated from coregistered PET using a Patlak graphical approach. The essential findings were as follows: (1) regional Kocc were highly correlated between the radiotracers and in agreement with a previous FDOPA studies that used different ROI selection techniques; (2) FMT Kocc were higher in extrastriatal regions of relatively large uptake such as amygdala, pallidum, brainstem, hippocampus, entorhinal cortex, and thalamus, whereas cortical Kocc were similar between radiotracers; (3) while subcortical uptake of both radiotracers was related to disease duration and severity, cortical uptake was not. These results suggest that FMT may have advantages for examining pathologic changes within allocortical loop structures, which may contribute to cognitive and emotional symptoms of PD.
Based on the levers of control (LoC) framework and contingency theory, this study examines the relationships among the sophistication of a firm’s performance measurement system (PMS), the firm’s ...emphasis on the interactive and diagnostic use of the PMS, and the organizational outcomes of the PMS. We also examine whether firm size moderates these relationships. Based on a survey of 276 midsized enterprises, this study provides empirical evidence of direct, positive relationships between both types of use and the benefits of a PMS. However, PMS sophistication positively moderates the relationship between interactive use and PMS benefits, but it negatively moderates the relationship between diagnostic use and PMS benefits. Thus, our study suggests that an increased emphasis on diagnostic use may reduce benefits for the firm when the PMS is more sophisticated. This result contributes to our understanding of why existing outcome effects of PMSs in the literature have been shown to be sometimes negative, positive or nonsignificant. We also find that, compared with smaller firms, larger firms benefit more from the interactive use of a PMS, whereas our results are robust for other contextual or structural variables.
Reticulated platelets are immature platelets circulating in blood; they reflect the activity of megakaryopoiesis in the bone marrow. Therefore, they can be used as a non-invasive test in patients ...with thrombocytopenia in various clinical conditions. The preferred method of analysis is by flow cytometry. However, there is an evident lack of analytical standardization, making it difficult to compare results obtained in different laboratories. Currently, two types of hematology analyzers are on the market offering fully automated measurement of reticulated or immature platelets: the high end analyzers manufactured by Sysmex (XE- and XN-series) and Abbott (CELL-DYN Sapphire). Although the methods are essentially different and cannot be used interchangeably, both have been proven to have clinical utility. Reticulated or immature platelet assays are useful for the differential diagnosis of thrombocytopenia and for monitoring bone marrow recovery after chemotherapy or stem cell transplantation. These assays may aid clinicians in platelet transfusion decisions when recovery from thrombocytopenia is imminent. In addition, preliminary findings indicate that there is a rationale for reticulated or immature platelets for risk stratification in acute coronary syndromes and for monitoring the effect of treatment with antiplatelet drugs in patients with coronary artery diseases. The aim of this paper is to present the present technology available for measuring reticulated platelets as well as an overview of the current status of clinical application. This overview also indicates that more research is needed before reticulated or immature platelet assays can be applied in other clinical conditions than thrombocytopenia and after transplantation.
The time course and magnitude of infarct involution, functional recovery, and normalization of infarct-related electrocardiographic (ECG) changes after acute myocardial infarction (MI) are not ...completely known in humans. We sought to explore these processes early after MI and during infarct-healing using cardiac MRI.
Twenty-two patients with reperfused first-time MI were examined by MRI and ECG at 1, 7, 42, 182, and 365 days after infarction. Global left ventricular function and regional wall thickening were assessed by cine MRI, and injured myocardium was depicted by delayed contrast-enhanced MRI. Infarct size by ECG was estimated by QRS scoring. The reduction of hyperenhanced myocardium occurred predominantly during the first week after infarction (64% of the 1-year reduction). Furthermore, during the first week the amount of nonhyperenhanced myocardium increased significantly (P<0.001), although the left ventricular mass remained unchanged. Left ventricular ejection fraction increased gradually, whereas the greater the regional transmural extent of hyperenhancement at day 1, the later the recovery of regional wall thickening. Regional wall thickening decreased progressively with increasing initial transmural extent of hyperenhancement (P(trend)<0.0001). The time course and magnitude of decrease in QRS score corresponded with the reduction of hyperenhanced myocardium.
The early reduction of hyperenhanced myocardium may reflect recovery of hyperenhanced, reversibly injured myocardium, which must be considered when predicting functional recovery from delayed contrast-enhanced MRI findings early after infarction. Also, the time course and magnitude for reduction of hyperenhanced myocardium were associated with normalization of infarct-related ECG changes.
Brown adipose tissue helps maintain normal body temperature in newborn humans but was thought to be absent in healthy adults. This report shows the presence of substantial amounts of metabolically ...active brown adipose tissue, as documented by biochemical, molecular, and morphologic criteria, and by a cold-induced glucose uptake in paracervical and supraclavicular adipose tissue that was increased by a factor of 15.
This report shows the presence of substantial amounts of metabolically active brown adipose tissue, as documented by biochemical, molecular, and morphologic criteria, and by a cold-induced glucose uptake in paracervical and supraclavicular adipose tissue that was increased by a factor of 15.
Active brown adipose tissue helps maintain normal body temperature in newborn infants. It is believed that this tissue regresses with increasing age and is completely lost by the time a person reaches adulthood.
1
However, the capacity to produce brown adipose tissue in adulthood has been shown in patients with catecholamine-secreting tumors such as pheochromocytomas and paragangliomas, in whom distinct brown-adipose-tissue depots develop.
2
,
3
When scanning with a combination of PET and computed tomography (CT) — with the glucose analogue
18
F-fluorodeoxyglucose (
18
F-FDG) as a tracer — is used in the diagnosis of neoplasms and their metastases, the results can be . . .
PDF
