Is there a causal relation between the administration of gadolinium based contrast media and the development of nephrogenic systemic fibrosis (NSF)?
Explore the source record for details and available documents.
Chelating Agents↗
Biomedical subjects
P Dawson
Publications and source records attributed to P Dawson.
Quality of fresh chicken breasts using a combination of modified atmosphere packaging and chlorine dioxide sachets.
The objective of this research was to observe the effect of chlorine dioxide (ClO2) combined with modified atmosphere packaging on the quality of fresh chicken breasts under refrigerated storage for 15 days. Each chicken breast was inoculated with a 4-log CFU/ml culture of Salmonella Typhimurium (nalidixic acid-resistant strain) and placed into a barrier foam tray. Fast- or slow-release ClO2 sachets were placed next to the chicken in each package. A control set of packages that did not contain a ClO2 sachet was also included in the study. Packages were flushed with either 100% N2 or 75% N2-25% CO2 and stored at 3 degrees C. Microbial analysis, CIE L.a.b. color, and sensory (appearance and aroma) were performed every 3 days for 15 days. Total plate counts for chicken increased steadily after 6 to 9 days of storage regardless of package atmosphere or ClO2 treatment. However, those treated with ClO2 sachets had 1 to 1.5 log CFU per chicken breast lower total plate counts compared with those without ClO2 sachets. After 15 days, samples treated with ClO2 (fast- and slow-release sachets) had significantly lower Salmonella Typhimurium (nalidixic acid-resistant strain) populations (approximately 1 log) compared with chicken that did not contain ClO2 sachets. The ClO2 adversely affected the color of the chicken in areas close to the sachet. No off-odor was detected by the sensory panelists.
Animals↗
Multi-slice CT contrast enhancement regimens.
Historically, the development of progressively faster Computed Tomography (CT) technology has dictated a recurrent need to re-examine intravenous contrast agent enhancement regimens. The most recently introduced development, the very fast, multi-slice helical/spiral systems, have raised the same issue yet again. It is possible, exploiting the technology to its maximum potential as regards speed, to perform an examination many times faster (depending on the number of detector rings from 4 to 64) even than with earlier single slice spiral instruments. In order to optimise image quality, such maximal speed gains will not usually be sought but, nevertheless, imaging time will generally be substantially reduced. It is natural that the question of a possible need to modify contrast agent enhancement protocols designed for an earlier generation of slower machines should again be considered. Using as a basis known contrast agent pharmacokinetics and results of modelling techniques, the matter is tackled in this paper.
Angiography↗
Anaesthesia for electroconvulsive therapy: a comparison of sevoflurane with propofol.
This study was a prospective audit of patients receiving either intravenous induction of anaesthesia with propofol 2 mg/kg or inhalational induction using 8% sevoflurane for patients undergoing electroconvulsive therapy (ECT). All patients received inhaled 50% nitrous oxide. The anaesthetic agent was determined by psychiatrist preference. Each psychiatrist nominated only one induction technique for all his or her patients. Seventy treatments were studied in each group. Induction time was longer in the sevoflurane group. The time from commencing induction to loss of verbal contact was [mean (SD)] 64 (29.9) seconds for sevoflurane and 36 (33.6) seconds for propofol (P=0.001). Time to loss of eyelash reflex was 82 (32.6)s for sevoflurane and 44 (17.9)s for propofol (P<0.001). The duration of seizure activity was longer in sevoflurane patients, 35 (17.8)s, compared with 20 (9.8)s in the propofol group (P< 0.001). Discharge times were similar Minor adverse effects occurred in three patients, all in the sevoflurane group (one bradycardia and two episodes of post-procedural nausea). There were no major adverse events in either group. Propofol and sevoflurane both appear to be suitable agents for induction of anaesthesia for ECT.
Adult↗
Patient dose in multislice CT: why is it increasing and does it matter?
A brief review is presented of the reasons why multislice spiral/helical CT is associated with a higher radiation dose burden to the patient even than incremental CT. These include both intrinsic technological and geometric factors as well as simply a growing use of CT in an increasing number of applications. The typical magnitude of this dose burden is indicated and the basis for the anxiety that underpins it, namely the linear no-threshold (LNT) hypothesis, is discussed, together with the countervailing hypothesis that there is indeed a threshold for radiation harm in man and that the radiation doses associated with CT may lie below this threshold and may even be beneficial (radiation hormesis). There are as yet no certainties in this important area but it is argued that it is not a given that the doses associated with CT are harmful.
Adolescent↗
Therapeutic potential of hammerhead ribozymes in the treatment of hyper-proliferative diseases.
The limited efficacy of current therapeutic approaches for a number of socially relevant human diseases such as cancer and cardiovascular pathologies, has required the exploration of alternative and more effective therapeutic strategies. In the last two decades, nucleic acid based drugs have emerged as an attractive and novel alternative with great therapeutic potential. Among these molecules, hammerhead ribozymes were the first to be extensively studied and predicted to be of potential practical utility. Hammerhead ribozymes are catalytic RNA molecules capable of inducing the site-specific cleavage of a phosphodiester bond within an RNA molecule. Thus, they can be used to reduce the intracellular level of a specific mRNA coding for a protein which affects cellular metabolism or environment, causing disease. As hammerhead ribozymes can be engineered to reduce the level of virtually any mRNA, they have a very broad applicability. Among the several pathological conditions amenable for a hammerhead ribozyme based therapeutic approach, we focused our attention on pathologies sustained by a dis-regulated and excessive cellular proliferation, being sure to properly demonstrate their usefulness. Trying to be as objective as possible in regard to the feasibility of hammerhead ribozyme employment as therapeutics, a technical section, describing some of the unresolved problems in this field, has been also included. Although some aspects of hammerhead ribozymes as therapeutics can and should be optimized, the encouraging results displayed so far fully justifies further efforts, economic and scientific, to bring them closer to the clinical practice.
Animals↗
Effects of acute liver injury on blood coagulation.
The mechanisms leading to the hemostatic changes of acute liver injury are poorly understood. To study these further we have assessed coagulation and immune changes in patients with acute paracetamol overdose and compared the results to patients with chronic cirrhosis and normal healthy controls. The results demonstrate that in paracetamol overdose coagulation factors (F)II, V, VII and X were reduced to a similar degree and were significantly lower than FIX and FXI (mean levels 0.28, 0.16, 0.13, 0.19, 0.51 and 0.72 IU mL(-1), respectively). In cirrhosis, by contrast, FII, FV, FVII, FIX and FX were equally reduced whilst FXI was lower than the other factors (mean levels 0.64, 0.69, 0.62, 0.60, 0.66 and 0.40 IU mL-1, respectively). FVIII was raised in paracetamol overdose patients but normal in those with cirrhosis (mean levels 1.95 and 1.01 IU mL(-1), respectively). Interleukin-6 and tumor necrosis factor-alpha levels were raised in both patient groups, but higher levels were found in paracetamol overdose, compared to cirrhosis. Thrombin-antithrombin and soluble tissue factor levels were higher in those with acute liver injury but normal in cirrhosis. Antithrombin levels were reduced in both acute liver injury and cirrhosis. From these data we put forward a novel mechanism for the coagulation changes in acute paracetamol induced liver injury. We propose that immune activation leads to tissue factor-initiated consumption of FII, FV, FVII and FX, but that levels of FIX and FXI are better preserved because antithrombin inhibits the thrombin induced positive feedback loop that activates these latter factors.
Acetaminophen↗
Can we help persons with dementia find their way in a new environment?
The objective of this study was to conduct a randomized controlled trial to examine the effects of a way-finding intervention on residents' ability to find their way in a new environment. The effect of the intervention on the residents' spatial orientation and agitation were also examined. The study was conducted on four nursing home units in a geriatric center and the final sample consisted of 32 residents with Alzheimer's disease (17 in the treatment group and 15 in the control group). The intervention consisted of the use of a location map and a behavioral training technique, which was provided to residents over the course of a month. Repeated measures analysis of variance and McNemar tests were used to compare the groups in regard to changes in the outcomes over time. Results indicated that the residents' in the treatment group demonstrated an increased ability to find their way to the dining room one week after the intervention. The intervention effect was not sustained three months later.
Activities of Daily Living↗
The physics of the oscillating bubble made simple.
The physics of bubbles and of their oscillations is extremely complex and attempts at its mathematical description are generally inaccessible. Yet some idea, in broad descriptive terms at least, is very helpful in understanding bubble phenomena of clinical interest. A brief attempt to provide such a description is given in this article.
Contrast Media↗
Allopurinol and superoxide dismutase protect against leucocyte-endothelium interactions in a novel model of colonic ischaemia-reperfusion.
BACKGROUND: Leucocyte recruitment is a key feature in ischaemia-reperfusion (I/R)-triggered tissue injury. However, the mechanisms underlying leucocyte-endothelium interactions in the large bowel remain elusive because of a previous lack of models to examine the colonic microcirculation. The aim of this study was to develop and validate a novel method for studying reperfusion-induced leucocyte-endothelium interactions in the colon. METHODS: The superior mesenteric artery was occluded for 30 min in male C57/Bl6 mice and leucocyte responses were analysed in colonic venules after 30-240 min of reperfusion. Analysis of leucocyte rolling and adhesion in colonic venules was made possible by an inverted approach using intravital fluorescence microscopy. RESULTS: Thirty minutes of ischaemia and 120 min of reperfusion induced the strongest and most reproducible increase in leucocyte rolling and adhesion. This was associated with a significant increase in colonic levels of malondialdehyde (MDA). Administration of allopurinol and superoxide dismutase reduced I/R-induced leucocyte responses in a dose-dependent manner. Pretreatment with allopurinol attenuated the tissue content MDA in the colon by more than 60 per cent. CONCLUSION: A new method for examining I/R-induced leucocyte responses in the colonic microcirculation is described. Oxygen free radicals play an important role in triggering leucocyte rolling and adhesion in colonic venules.
Allopurinol↗
Assessing the effectiveness of critical pathways on reducing resource utilization in the surgical intensive care unit.
OBJECTIVES: To evaluate the effectiveness of procedure-specific surgical critical pathways on reducing resource utilization in a university surgical intensive care unit (ICU). DESIGN AND SETTING: Prospective cohort study in a university surgical ICU. PATIENTS: 194 patients, accounting for 255 patient days, sampled on randomly selected days over a 12-month period of time. MEASUREMENTS AND RESULTS: The primary outcomes of this study were pathway eligibility and laboratory utilization. Patients were eligible for a procedure-specific pathway in 34% of patient days identified, and the patient's clinical course was "on" pathway in 22% of patient days. Of those "on" the pathway, 54% had a pathway present in the chart and 32% of these included documentation of the patient's clinical course. Thus in 78% of the patient days the patient was either not eligible for a critical pathway or the patient's clinical course was "off" pathway. In those patients "on" the pathway 46 % did not have a pathway present in the chart. Being on a critical pathway did not reduce laboratory utilization. Laboratory utilization did not vary between patients "on" and "off" the pathway (19.1 +/- 11.3 laboratory tests/patient day versus 20.4 +/- 5.7 laboratory tests/patient day). Predicted laboratory utilization by the pathway was 5.6 laboratory tests/patient day. By reducing actual laboratory utilization to that predicted by the critical pathway we would reduce laboratory utilization at our institution by $1.2 million per year. CONCLUSIONS: Procedure-specific surgical critical pathways are not an effective tool for reducing resource utilization in our ICU. Most of our patients were not eligible for an available pathway, and those who were eligible and were "on" the pathway did not appear to have laboratory utilization guided by the pathway. Future initiatives need to explore other means such as ICU-specific care processes to reduce resource utilization in the ICU.
Aged↗
Imaging tip formation in single-mode optical fibres.
The formation of probe tips is a crucial step in all forms of scanning probe microscopy (SPM). In this work single-mode optical fibres are chemically etched in a variable temperature bath of etchant solution (HF acid buffered with ammonium fluoride) to produce tips for optical SPM. Tip evolution is monitored by prematurely truncating the etching process and imaging the tip end-structure using atomic force microscopy (AFM). In the case of a visible regime single-mode fibre the AFM images show a remarkable ring structure in the central cladding region and a tip structure in the core with a central depression; this serves to demonstrate the efficacy of chemical etching for converting compositional variation to three-dimensional topography. In the case of a standard, single-mode optical communications fibre the (projected) tip cone angle is assessed from AFM images in the early stages of tip formation. Values of the cone angle thus determined, for different etch conditions, are compared to those predicted by a model in which the independently determined core and cladding etch rates, and core diameter are the sole determinants of the final tip geometry. The model was devised in the context of etching multi-mode fibres and is shown to be valid here for single-mode fibres within the range of experimental accuracy and etch conditions examined.
Journal Article↗
Patient-controlled analgesia and intra-operative suggestion.
In a double-blind randomised study, we investigated the influence of positive intra-operative suggestions, presented to anaesthetised patients undergoing total abdominal hysterectomy, on postoperative pain, nausea and vomiting. One hundred and forty patients were randomly allocated to listen to one of four tapes containing either white noise or positive suggestions. The positive suggestions related to pain, postoperative nausea and vomiting, or both. We found that the positive intra-operative suggestions had no beneficial effects in reducing postoperative pain or nausea scores, nor was the consumption of morphine or anti-emetics reduced.
Adult↗
An international collaborative study to establish a World Health Organization international standard for hepatitis B virus DNA nucleic acid amplification techniques.
BACKGROUND AND OBJECTIVES: Twenty-two laboratories from nine countries participated in an international collaborative study to establish a World Health Organization (WHO) international standard for hepatitis B virus (HBV) DNA nucleic acid amplification techniques (NAT). MATERIALS AND METHODS: Three samples, AA, BB (both of which were lyophilized) and CC (which was a liquid preparation), were analysed using several different NAT assays. The mean HBV DNA content of each sample was determined from the study. RESULTS: Despite the range of assays (commercial and in-house) used by participants, there was good agreement among the overall mean 'equivalents'/ml obtained by the different assays, except for one laboratory (laboratory 4). The variation in estimates of log10 'equivalents'/ml was 1.75-1.25 for the three samples if results from laboratory 4 were excluded. The mean log10 'equivalents'/ml for all laboratories were 6.42 for sample AA, 6.30 for sample BB and 5.03 for sample CC (exclusion of results from laboratory 4 made little difference). The difference in titres between the two lyophilized samples (AA and BB) was not statistically significant but the titre of the frozen sample (CC) was significantly lower. Material AA (code 97/746) was accepted as the first WHO international standard for HBV DNA NAT assays and assigned a potency of 10(6) international units (IU)/ml. CONCLUSIONS: The titres (genome equivalents/ml) of three HBV preparations were determined by several laboratories using different NAT assays. This study enabled the establishment of an international standard, 97/746, for HBV DNA NAT assays.
DNA, Viral↗
Re: impact factors or commonsense.
Explore the source record for details and available documents.
Bibliometrics↗
Multi-slice technology in computed tomography.
Multi-slice systems represent a considerable advance in CT and will assure the future of the technique for many years to come. This article describes this new technology, indicating its provenance and its position in the evolution of CT. While it does not seek to be a physics and engineering text, enough detail of these are given to allow an informed discussion of the many advantages and a few potential problems associated with the technology. A discussion of a number of applications and a brief consideration of contrast enhancement regimens and the possible need for their modification are presented.
Equipment Design↗
Assessing growth patterns.
Explore the source record for details and available documents.
Body Height↗