An automated ionization chamber for secondary radioactivity standards

I report on the operation and characterization of a new ionization chamber system, "AUTOIC", featuring a commercial digital electrometer and a commercial robotic sample changer. The relative accuracy of the electrometer was improved significantly beyond the manufacturer's specifications through an in-house calibration of the various ranges, applied via software. The measurement precision and repeatability of the system have been determined by measuring multiple samples of the same radionuclide over the span of two or three years. The linearity of the system was examined by following the decay of (99m)Tc, (99)Mo and (133)Xe sources for up to 19 half-lives and determining half-life values. All of these values agree with the accepted literature values, within their combined uncertainties.

A new primary standardization of 229Th

The National Institute of Standards and Technology (NIST) has certified a high-purity (229)Th Standard Reference Material as SRM 4328C, based on live-timed 4pialphabeta-gamma anticoincidence counting (LTAC) of the equilibrium solution. The LTAC system was optimized to minimize the uncertainty in the result due to the two short-lived ground-states present in the decay chain. Confirmatory measurements were carried out by four other methods. Furthermore, the present absolute activity and measured gamma-ray emission rates were combined to obtain gamma-ray emission probabilities.

'Lazy, slothful and indolent': medical and social perceptions of obesity in Europe to the eighteenth century

There is a considerable stigma associated with obesity, among healthcare professionals as well as the general population, which often leads to discrimination and weight bias. But why is there a stigma attached to obesity? The origin of this stigma has been identified in the 18th century but its roots lie much further back in history. There is some debate about how this negative perception of obesity arose and the role of medical professionals in its creation. This paper examines both positive and negative conceptions by following three major aspects of the modern stigma through from Palaeolithic statues to the medical texts of ancient Greece and Rome, finishing with the medical and literary sources of the 18th century 'Enlightenment'. The modern perception of obesity originated in the social and scientific climate of the Enlightenment through the combination of three key themes; obesity as conspicuous consumption, associations with suspect morals and excess, and as an outward representation of the soul. The evolution of each of these themes can be clearly identfied in pre-Enlightenment sources. By the eighteenth century, these perceptions became amplified by, and disseminated through, the literary and media boom to create a recognisably modern stigma against the obese.

Standardization of (68)Ge/(68)Ga Using Three Liquid Scintillation Counting Based Methods

A solution containing (68)Ge in equilibrium with its daughter, (68)Ga, has been standardized for the first time at the National Institute of Standards and Technology (NIST) using 3 liquid scintillation-based techniques: live-timed 4πβ -γ anticoincidence (LTAC) counting, the Triple-to-Double Coincidence Ratio (TDCR) method, and (3)H-standard efficiency tracing with the CIEMAT(1)/NIST (CNET) method. The LTAC technique is much less dependent on level scheme data and model-dependent parameters and was thus able to provide a reference activity concentration value for the master solution with a combined standard uncertainty of about 0.3 %. The other two methods gave activity concentration values with respective differences from the reference value of +1.2 % and -1.5 %, which were still within the experimental uncertainties. Measurements made on the NIST "4π"γ secondary standard ionization chamber allowed for the determination of calibration factors for that instrument, allowing future calibrations to be made for (68)Ge/(68)Ga without the need for a primary measurement. The ability to produce standardized solutions of (68)Ge presents opportunities for the development of a number of NIST-traceable calibration sources with very low (<1 %) relative standard uncertainties that can be used in diagnostic medical imaging.

An apparent phaeochromocytoma and abnormal thyroid function tests

A 41-year-old lady presented with classical symptoms of a phaeochromocytoma and markedly elevated urinary adrenaline concentration. Urinary fractionated metanephrine and normetanephrine concentrations were within the normal reference range. Computed tomography of the abdomen/pelvis and I123 meta-iodobenzylguanidine scans were negative. Factitious adrenaline use was established as the diagnosis.

Liquid-scintillation-based anticoincidence counting of Co-60 and Pb-210

The method of liquid-scintillation-based 4pibeta-gamma anticoincidence counting was employed to assay the radioactivity concentration of acid solutions containing radionuclides (60)Co and (210)Pb (in equilibrium with its daughters). The limiting factors on the accuracy for such activity measurements and suggestions for minimizing such factors are reported.

A liquid-scintillation-based primary standardization of 210Pb

A new radioactivity solution standard of 210Pb has been developed and will be disseminated by the National Institute of Standards and Technology (NIST) as standard reference material (SRM) 4337. This new 210Pb solution standard is contained in a 5 mL flame-sealed borosilicate glass ampoule, consists of (5.133+/-0.002)g of a nominal 1mol L(-1) nitric acid solution, has a density of (1.028+/-0.002)g mL(-1) at 20 degrees C, has carrier ion concentrations of about 11 microg Pb2+ and 21 microg Bi3+ per gram of solution, and is certified to contain a massic activity (9.037+/-0.22)kBq g(-1) as of the reference time 1200 EST, 15 June 2006. All of the uncertainties cited above correspond to standard uncertainties multiplied by a coverage factor k=2. The standardization for the (210)Pb content of the solution was based on 4pialphabeta liquid scintillation (LS) measurements using CIEMAT/NIST (3)H-standard efficiency tracing (CNET). Confirmatory determinations were also performed by high-resolution HPGe gamma-ray spectrometry, by 2pialpha spectrometry with a Si surface barrier detector of separated 210Po, and by 4pibeta(LS)-gamma(NaI) anticoincidence counting.

Trends in genital chlamydia infection in the Mid-West of Ireland, 2001-2006

Genital Chlamydia trachomatis (GCT) infection is the most common bacterial sexually transmitted infection (STI) in Ireland. A retrospective analysis of 2,087 laboratory-confirmed GCT patient episodes from 2001 to 2006 in the Mid-West of Ireland was undertaken in conjunction with statutorily notifiable data that were reported by the Sexually Transmitted Disease/Genito-Urinary Medicine (STD/GUM) services in the region and used in national surveillance. Data were analysed by year, source, sex and age. The annual incidence of GCT in the Mid-West is increasing. A substantial proportion of GCT infections were diagnosed in the non-STD/GUM setting. The issue of sexually active young people seeking STI screening is a sensitive one, and delays increase the potential for transmission and the possibility of long-term complications when the disease is not treated. Based on this sample, national surveillance would significantly underestimate the burden of disease in Ireland, due to under-reporting. This would have implications for any national chlamydia screening programme. Among those who sought testing, women aged 15 to 19 years are five times more likely to be found positive than men in the same age group. Of those diagnosed in the non-STD/GUM setting, 83% were women. General practitioners and clinicians might consider targeting those aged 15 to 29 years for opportunistic screening and sexual health advice. Contact tracing and follow-up in the non-STD/GUM setting, as well as access for general practitioners to ongoing education on STIs are challenges to be addressed.

Norovirus outbreak associated with a hotel in the west of Ireland, 2006

An outbreak of gastrointestinal disease (nausea, vomiting or diarrhoea) occurred among a party of wedding guests, staff and other guests in a hotel in the west of Ireland, in October 2006. Upon notification, a multi-disciplinary outbreak control team was convened to investigate and control the outbreak. In all, 98 people were ascertained ill. The median duration of illness was 48 hours. The attack rate ranged between 48 and 85%. The hotel voluntarily notified health authorities and co-operated fully with investigation and control measures. Strict prevention and control measures were instituted promptly, including air ventilation, enhanced hand hygiene, isolation of cases, temporary "cooked food only", temporary alternative accommodation and specialised cleaning. Three cases of norovirus infection were laboratory-confirmed. There was no evidence of food- or water-borne transmission. Clinical and epidemiological findings indicated person-to-person transmission of norovirus. This report highlights the potential for large social gatherings to facilitate the spread of viral gastroenteritis by person-to-person transmission and via contaminated environment. Effective community management of this outbreak appears to have prevented its having an impact on local acute hospital services. The authors conclude that in addition to the existing national guidelines on the management of outbreaks of norovirus in healthcare settings, agreed guidelines for the management of norovirus outbreaks in the hotel and tourism industry are needed in Ireland.

Hereditary diffuse gastric cancer: Natural history, pathology, screening limitations, and prophylactic total gastrectomy in CDH1 mutation carriers

4500

Background: Hereditary diffuse gastric cancer (HDGC) is a potentially fatal disease that occurs due to mutations in the E- cadherin (CDH1) gene, as discovered in 1998. Its penetrance ranges between 70–80%. Its morbidity and mortality can be altered favorably through genetic counseling, germline mutation testing, and highly-targeted management that includes prophylactic total gastrectomy. Lobular breast cancer has been identified as an integral lesion in HDGC. Methods: This international collaborative group on HDGC is comprised of 56 mutation-positive families, which is the world’s largest resource of such families. Cancer diagnoses were verified with pathology slides/tissue block review when possible, or reports. Genetic counseling covering the pros and cons of mutation testing, screening and its limitations, and the option of prophylactic total gastrectomy was provided. Results: Findings on 56 HDGC mutation-positive families show carrier testing to have been performed on 267 individuals, of which 123 were CDH1 mutation positive. Prophylactic gastrectomies were performed on 14 families involving 50 individuals. Occult cancer was diagnosed in 31 (31/39=79.5%; results are pending on the remaining 11), based upon pathology and verbal reports. Five individuals underwent prophylactic gastrectomy prior to genetic counseling, 3 of whom later tested negative for mutations. In one of these remarkable HDGC families, 11 first cousins who tested positive for the CDH1 mutation underwent prophylactic total gastrectomy. On a post-surgery questionnaire, they each stated that the decision for the prophylactic procedure was the “right one” for them. In each case, a parent had died of HDGC sequelae, adding to the cousins’ acceptance of DNA testing and surgery. They considered their post-operative nutritional programs to have been acceptable. Conclusion: HDGC and its life-threatening sequelae were significantly ameliorated in CDH1 mutation carriers through total prophylactic gastrectomy in patients at enormous lifetime risk for HDGC. Decision for mutation testing and surgery may be more acceptable through intensive education in concert with a compassionate management team.

No significant financial relationships to disclose.

Effects of Financial Incentives on the Intention to Consent to Organ Donation: A Questionnaire Survey

INTRODUCTION

Shortage of donor organs is a serious problem for transplantation medicine. One controversial suggestion to increase the number of organ donors is financial incentives for consent. The aim of this study was to test whether different forms and amounts of financial incentives were apt to increase the consent to organ donation.

MATERIALS AND METHODS

Data were collected via questionnaires in urban and rural regions of Austria and randomly assigned to settings with three different amounts of financial incentives. The questionnaire was designed by using the theory of planned behaviour of Ajzen. Parents 69 mothers and 35 fathers; ages 25 to 65 years were evaluated for intention to consent to organ donation, perceived social norm, and positive/ negative aspects of organ donation without and with various financial incentives.

RESULTS

The intention to consent to organ donation dropped highly significantly (Z = -7.556 P = .000) from the basic condition (M = 1.13; confidence interval [CIs] 0.78 to 1.51) to the condition with financial incentives (M = -1.58; CI, 1.96 to -1.15). No influence of the amount of financial incentive was observed. Highly significant differences were measured between both conditions for the social norm (Z = -5.638; P < .000) and the attitude toward organ donation (Z = -1.962; P < .05; Z = -2.104; P < .035).

CONCLUSIONS

Financial incentives led to decreased consents and elicited strong rejections and negative reactions of the participants. Taking money for consent to organ donation seems to be a strict taboo for most people in Austrian society.

A retrospective study of New Zealand case law involving assisted reproduction technology and the social recognition of ‘new’ family

The New Zealand Human Assisted Reproductive Technology (HART) Act became law in 2004. In this article, we provide a retrospective analysis of New Zealand case law from September 1990 to March 2004, leading up to the creation of the HART Act. We examine the new understandings of parenting (developed through the routine use of ART in New Zealand) which the case law attempted to test. We examine these concepts against the previous understandings of family enshrined in the pre-existing legislation, which formed the basis for judicial rulings in the various cases to which we refer. In conclusion, we provide a brief summary of the 2004 HART legislation and draw comparisons between the old and new legislative and bureaucratic frameworks that define and support New Zealand family structure. We suggest that a change in cultural backdrop is occurring from the traditional western ideology of the nuclear family towards the traditional Maori concept of family formation, which includes a well-accepted traditional practice of guardianship and a more open and extended family structure. This 'new' structure reflects the contemporary lived experience of family kinship in western societies as individualized and open to choice.

Elastic scattering spectroscopy accurately detects high grade dysplasia and cancer in Barrett's oesophagus

BACKGROUND AND AIMS

Endoscopic surveillance of Barrett's oesophagus currently relies on multiple random biopsies. This approach is time consuming, has a poor diagnostic yield, and significant interobserver variability. Elastic scattering spectroscopy is a real time in vivo optical technique which detects changes in the physical properties of cells. The aim of this study was to assess the potential for elastic scattering to detect high grade dysplasia or cancer within Barrett's oesophagus.

METHODS

Elastic scattering spectroscopy measurements collected in vivo were matched with histological specimens taken from identical sites within Barrett's oesophagus. All biopsies were reviewed by three gastrointestinal pathologists and defined as either "low risk" (non-dysplastic or low grade dysplasia) or "high risk" (high grade dysplasia or cancer). Two different statistical approaches (leave one out and block validation) were used to validate the model.

RESULTS

A total of 181 matched biopsy sites from 81 patients, where histopathological consensus was reached, were analysed. There was good pathologist agreement in differentiating high grade dysplasia and cancer from other pathology (kappa = 0.72). Elastic scattering spectroscopy detected high risk sites with 92% sensitivity and 60% specificity and differentiated high risk sites from inflammation with a sensitivity and specificity of 79%. If used to target biopsies during endoscopy, the number of low risk biopsies taken would decrease by 60% with minimal loss of accuracy. A negative spectroscopy result would exclude high grade dysplasia or cancer with an accuracy of >99.5%.

CONCLUSIONS

These preliminary results show that elastic scattering spectroscopy has the potential to target conventional biopsies in Barrett's surveillance saving significant endoscopist and pathologist time with consequent financial savings. This technique now requires validation in prospective studies.

Initially elevated osteoprotegerin serum levels may predict a perioperative myocardial lesion in patients undergoing coronary artery bypass grafting

OBJECTIVE

We investigated whether osteoprotegerin (OPG), an important regulator in the genesis of arteriosclerosis and bone formation, is able to identify patients at risk for perioperative myocardial infarction measured as cardiac troponin I (cTNI) and signs of myocardial ischemia in the electrocardiogram after coronary artery bypass grafting (CABG).

DESIGN

Observational study.

SETTING

Post-surgical intensive care unit of a tertiary care center.

PATIENTS

Ninety-seven patients undergoing elective CABG.

INTERVENTIONS

None.

MEASUREMENT AND MAIN RESULTS

OPG and cTNI were measured before and 24 hrs after CABG. Additionally, cTNI was measured after 12 hrs. Electrocardiography was done before and immediately after CABG. OPG before CABG (OPGpre) measurements correlated with cTNI measurements after 12 hrs (cTNI12) (r = 0.56; p < .0001) and with cTNI measurements after 24 hrs (cTNI24) (r = 0.77; p < .0001). OPGpre measurements correlated with electrocardiographic findings after surgery (r = 0.65; p < .0001). There was a positive correlation between OPGpre value and the number of bypasses (r = 0.95; p < .0001). A strong correlation was found between OPGpre and homocysteine (r = 0.96; p < .0001). The median OPG presurgical level for the four patients with cardiac complications was found to be notably elevated (28.1 [26.6/31.0] pmol/L) in comparison with that for patients without complications (10.2 [3.7/16.9] pmol/L).

CONCLUSIONS

OPG appears to be a useful marker for estimating risk for perioperative myocardial infarction in patients undergoing CABG, as demonstrated by signs of ischemia on electrocardiography.

Strength of the 18F(p,alpha)15O resonance at Ec.m. = 330 keV

Production of the radioisotope 18F in novae is severely constrained by the rate of the 18F(p,alpha)15O reaction. A resonance at E(c.m.)=330 keV may strongly enhance the 18F(p,alpha)15O reaction rate, but its strength has been very uncertain. We have determined the strength of this important resonance by measuring the 18F(p,alpha)15O cross section on and off resonance using a radioactive 18F beam at the ORNL Holifield Radioactive Ion Beam Facility. We find that its resonance strength is 1.48+/-0.46 eV, and that it dominates the 18F(p,alpha)15O reaction rate over a significant range of temperatures characteristic of ONeMg novae.

The effect of temperature on non-specific defence parameters of three strains of juvenile Atlantic halibut (Hippoglossus hippoglossus L.)

The effect of temperature (8, 12, 15 and 18 degrees C) on a variety of non-specific defence and haematological parameters was examined in three geographically distinct reared strains (Canadian, Icelandic, Norwegian) of Atlantic halibut. The results indicate that temperature exerts a considerable influence on some blood parameters (packed cell volume and the percentage population of leucocytes in peripheral blood) and on some humoral parameters (serum lysozyme activity and serum protein levels) of halibut. A high temperature of 18 degrees C caused a decrease in the number of circulating blood cells and an increase in serum lysozyme levels; effects consistent with those reported within the literature for stress. The different strains of halibut exhibited differing responses with respect to differential counts of peripheral blood lymphocytes and thrombocytes, and to serum protein concentrations, serum lysozyme activity, serum iron content, unsaturated iron binding capacity of serum and O2- production by kidney macrophages.

Error in radiology

Literature review indicates high levels of error within radiology. The aetiology of radiological error is multi-factorial. While individuals have a duty to progressively improve their performance, the experience of safety cultures in other high-risk human activities has shown that a system approach of root cause analysis is the method required to reduce error significantly.

Ninety-minute accelerated critical pathway for chest pain evaluation

Rapid, efficient, and accurate evaluation of chest pain patients in the emergency department optimizes patient care from public health, economic, and liability perspectives. To evaluate the performance of an accelerated critical pathway for patients with suspected coronary ischemia that utilizes clinical history, electrocardiographic findings, and triple cardiac marker testing (cardiac troponin I [cTnI], myoglobin, and creatine kinase-MB [CK-MB]), we performed an observational study of a chest pain critical pathway in the setting of a large Emergency Department at the Veterans Affairs Medical Center in 1,285 consecutive patients with signs and symptoms of cardiac ischemia. The accelerated critical pathway for chest pain evaluation was analyzed for: (1) accuracy in triaging of patients within 90 minutes of presentation, (2) sensitivity, specificity, positive predictive value, and negative predictive value of cTnI, myoglobin, and CK-MB in diagnosing acute myocardial infarction (MI) within 90 minutes, and (3) impact on Coronary Care Unit (CCU) admissions. All MIs were diagnosed within 90 minutes of presentation (sensitivity 100%, specificity 94%, positive predictive value 47%, negative predictive value 100%). CCU admissions decreased by 40%. Ninety percent of patients with negative cardiac markers and a negative electrocardiogram at 90 minutes were discharged home with 1 patient returning with an MI (0.2%) within the next 30 days. Thus, a simple, inexpensive, yet aggressive critical pathway that utilizes high-risk features from clinical history, electrocardiographic changes, and rapid point-of-care testing of 3 cardiac markers allows for accurate triaging of chest pain patients within 90 minutes of presenting to the emergency department.

Application of a wind model for the El Paso-Juarez airshed

A time-dependent, 3-dimensional mesoscale model, version 5 (MM5), developed by the Penn State University and the National Center for Atmospheric Research, was applied to study the meteorology over complex terrain of the El Paso-Juarez area. MM5 meteorological output data were compared against experimental data from the Texas Natural Resource Conservation Commission on days of reported high ozone concentrations. Model runs were conducted for a 36-, 12-, 4-km grid arrangement. Results indicate that the dispersion of pollutants by wind plays a significant role on days of low peak ozone concentration.

Mitigation of the clinical significance of spurious elevations of cardiac troponin I in settings of coronary ischemia using serial testing of multiple cardiac markers

The ability to differentiate between true positives, false positives, and sporadically elevated cardiac troponin levels has grown in importance as cardiac troponins assume an increasingly dominant role in the diagnosis of coronary syndromes. In a population sample of 1,000 patients who presented consecutively to a large urban hospital emergency room, 50 of 112 patients who had elevated troponin levels (> 0.6 ng/ml) during evaluation for myocardial injury were subsequently found to have had an isolated, spurious elevation of cardiac troponin, and not a diagnosed myocardial infarction. Logistic regression analysis shows that by hierarchically analyzing electrocardiographic changes with concurrent creating kinase-MB and myoglobin levels at the time of the troponin elevation, one may predict with 91% accuracy whether the troponin elevation is actually indicative of a myocardial infarction in a patient. Spurious troponin elevations may be a common occurrence, and if not detected, may result in an increased number of falsely diagnosed myocardial infarctions.

Usefulness of cardiac troponin I in patients undergoing open heart surgery

BACKGROUND

Significant myocardial injury during cardiac surgery is associated with a 10-fold increase in 2-year complication rates, yet there remains no clinical gold standard for diagnosis. Troponin I has complete cardiospecificity and is clinically used for diagnosis of myocardial infarction in other settings.

METHODS AND RESULTS

One hundred consecutive patients undergoing open heart surgery (71 coronary artery bypass grafts and 29 aortic valve replacements) were enrolled and blood samples were drawn preoperatively, at 5 AM and 5 PM on days 1 and 2 after surgery, and at 5 AM for 3 more days. Twelve-lead electrocardiograms were performed daily and echocardiographic studies were performed on patients with either; electrocardiographic changes signifying likely myocardial damage, intraoperative complications, or elevated creatine kinase subfraction MB or troponin values. Seventeen patients had either new wall motion abnormalities or new Q waves all with peak cardiac troponin I >40 ng/mL. Stratification of patients by peak troponin values <40 and >60 ng/mL was highly predictive (P <.001) of days in intensive care unit, days on ventilator, development of new arrhythmia, and especially cardiac events. These postoperative variables also showed a stronger correlation with peak cardiac troponin I than did peak creatine kinase subfraction MB.

CONCLUSION

Peak troponin I values detect myocardial infarction the day after heart surgery and predicts patient outcome.

Acid, helicobacter and immunity: a new paradigm for oesophagogastric cancer

Epidemiological evidence has clearly shown a highly significant relationship between Helicobacter pylori infection and the development of duodenal ulcer and distal gastric adenocarcinoma. Despite H. pylori being a common aetiological factor for both disorders, the two disease phenotypes are virtually mutually exclusive. This indicates that the host response to infection has a pivotal role in determining outcome; these disease phenotypes relate to the effect of infection on gastric acid secretion, duodenal ulcer being closely related to sustained acid secretion whereas gastric cancer follows gastric atrophy and impaired gastric acid secretion. Cancer at the oesophageal junction and that associated with Barrett's oesophagus is now the most rapidly increasing tumour in the gastrointestinal tract. The challenge for the next millennium, therefore, is to try and develop methods for identifying patients at risk of developing oesophagogastric cancer. A common feature in the pathogenesis of both gastric and oesophageal adenocarcinoma is inflammation presenting clinically as gastritis and oesophagitis. The pathway from gastritis to gastric atrophy, dysplasia and carcinoma is thought to be a multi-step process, probably triggered by free radicals within the gastric epithelium and increased exposure to luminal carcinogens. However, it has been unclear as to which aspect of the host response determines whether an individual will move along the neoplasia pathway. Recent work has shown that qualitative aspects of the immune environment in the stomach may account for a substantial part of the phenotypic divergence following H. pylori infection. Interleukin-1 beta polymorphisms relate closely to the propensity for an individual to develop distal gastric cancer and maybe useful for predicting risk in family members. In Barrett's oesophagus, we have recently shown that the immune environment may also be important in determining whether an individual will develop cancer. Although we did not find that Barrett's oesophagus was a profoundly inflammatory condition (unlike esophagitis in the squamous epithelium), where there was evidence of inflammation it was qualitatively different from that of oesophagitis in that a Th-2 response with increased expression of IL-4 predominated in Barrett's, whereas a Th-1 proinflammatory response characterised oesophagitis in squamous epithelium. It seems likely that the specific immune environment within Barrett's metaplasia may be an important driver towards dysplasia and carcinoma. Thus, the immune environment in the stomach and esophagus may be critical in determining whether an individual is at risk of developing neoplastic complications of H. pylori infection and gastroesophageal reflux. Identification of the genetic factors which underpin these responses may ultimately result in development of methods to identify individuals at high risk.

Spiral CT for suspected pulmonary embolism

Fitzgerald, Dr R. (2000). Clinical Radiology55, 983.

Naloxone-resistant respiratory depression and neurological eye symptoms after intrathecal morphine

We describe a case of neurological symptoms after the intrathecal use of an opioid. These symptoms were not reversible by the use of an opioid-antagonist.

A comparison of troponin T and troponin I as predictors of cardiac events in patients undergoing chronic dialysis at a Veteran's Hospital: a pilot study

OBJECTIVE

The purpose of this study was to prospectively evaluate the usefulness of the cardiac troponins as predictors of subsequent cardiac events in patients with chronic renal failure undergoing dialysis.

BACKGROUND

Cardiac troponin T (cTnT) and I (cTnI) are cardiac markers that are specific for cardiac muscle. They are also excellent prognostic indicators for patients presenting with chest pain. Although cardiac disease is the leading cause of death in dialysis patients, standard methods to diagnose acute coronary syndromes in patients with renal failure are often misleading.

METHODS

A six-month prospective study was done in a university-affiliated Veterans Hospital's dialysis clinic. Forty-nine patients undergoing chronic dialysis with no complaints of chest pain were followed for cardiac events occurring in the six months after cardiac troponin measurements. These included unstable angina, acute myocardial infarction and cardiac death. An additional 83 patients with renal failure but who were not undergoing dialysis were also examined.

RESULTS

Within six months all three dialysis patients with elevated cTnI at entry into the study suffered an adverse complication (specificity and positive predictive value = 100%). Twenty-five patients had cTnT elevated at >0.10 ng/ml (53%). Patients with diabetes were more likely to have elevated troponin T levels (64% vs. 25%, p = 0.01). All six patients developing cardiac events within three months had elevations of cTnT >0.1 ng/ml (sensitivity = 100%). Whereas the specificity of cTnT was only 56% for a near-term cardiac event, the negative predictive value of cTnT using a cutoff of < or = 0.1 ng/ml was 100%. On restratifying patients using a cutoff value of cTnT of >0.2 ng/ml, only nine of 49 dialysis patients (18%) had elevated levels. In patients with renal failure not undergoing dialysis, only three of 83 (4%) had elevated troponin I or T. None of these patients suffered a cardiac event in the next six months.

CONCLUSIONS

This prospective pilot study clearly delineates the troponins as important prognosticators in asymptomatic otherwise "stable" patients on chronic dialysis, especially those with concomitant diabetes mellitus. It also appears that troponins are more likely to be elevated in dialysis patients than other patients with renal failure not on dialysis. The above suggests that the combination of cTnI and cTnT might be very effective in elucidating cardiac risks of patients with renal failure undergoing chronic dialysis.

Extracerebral organ dysfunction and neurologic outcome after aneurysmal subarachnoid hemorrhage

OBJECTIVE

To analyze the influence of extracerebral organ system dysfunction after aneurysmal subarachnoid hemorrhage (SAH) on mortality and neurologic outcome.

DESIGN

Observational study with retrospective data extraction.

SETTING

Neurosurgical intensive care unit (NICU) at a primary level university hospital, supervised and staffed by both members of the Clinic of Neurosurgery and the Clinic of Anesthesiology and General Intensive Care.

PATIENTS

Two hundred forty-two patients treated for intracranial aneurysm rupture within 7 days of the most recent SAH.

INTERVENTIONS

Routine neurosurgical interventions for obliteration of the ruptured aneurysm (microsurgery, Guglielmi Detachable Coils embolization) and for treatment of posthemorrhagic hydrocephalus (ventriculostomy, cerebrospinal fluid shunt implantation).

MEASUREMENTS AND MAIN RESULTS

Respiratory, renal, hepatic, cardiovascular, and hematologic organ system functions were evaluated both individually and in aggregate by using a modified version of the Multiple Organ Dysfunction (mMOD) score. Of 1,452 organ system functions assessed in 242 patients during their NICU stay, 714 organ system functions were intact (cerebral: 0, extracerebral: 714), 556 organ systems had mild-to-moderate dysfunctions (mMOD scoremax 1-2 for the affected organ system; cerebral: 153, extracerebral: 403), and 182 organ systems failed (mMOD scoremax 3 for the affected organ system; cerebral: 89, extracerebral: 93). Severity of extracerebral organ system dysfunctions correlated with the degree of neurologic impairment (Hunt and Hess [H&H] score) in a graded fashion. Similarly, the chance to develop systemic inflammatory response syndrome (SIRS) during the NICU stay increased with increasing admission H&H grade. The incidence of SIRS and septic shock was 29% and 10.3%, respectively. The mortality rate was 40.2% in patients with SIRS and 80% for patients suffering septic shock. Seventy-seven percent of extracerebral organ system failures (OSFs) occurred in conjunction with SIRS: 51% of respiratory OSFs, 97% of renal OSFs, 100% of hepatic OSFs, 96% of cardiovascular OSFs, and 73% of hematopoietic OSFs. Both CNS dysfunction and extracerebral organ system dysfunctions were significantly related to neurologic outcome. The probability of unfavorable neurologic outcome significantly increased with both decreasing cerebral perfusion pressure (CPP) and increasing severity of extracerebral organ dysfunction.

CONCLUSION

Aneurysmal SAH and its neurologic sequelae accounted for the principal morbidity and mortality in the current series. Development of extracerebral organ system dysfunction was associated with a higher probability of unfavorable neurologic outcome. Systemic inflammation (SIRS) and secondary organ dysfunction were the principal non-neurologic causes of death.

Going Nondispersive

: The energy-dispersive Si(Li) X-ray spectrometer, introduced 30 years ago into electron probe microanalysis (EPMA) by R. Fitzgerald et al., has profoundly affected the development of microanalysis. It offers many advantages over the wavelength-dispersive crystal spectrometer. It has no moving parts and covers the full energy range of interest in EPMA. There is no defocusing over large distances on the specimen, the efficiency of the device is high, varies slowly and continuously with atomic number, and can be predicted fairly accurately, and, most importantly, all emission lines are detected and can be observed simultaneously. The one remaining disadvantage of the Si(Li) spectrometer is its poorer energy resolution. Solid-state detection devices now under development promise to achieve resolution comparable to that of the crystal spectrometer.

Conservative surgical management of bilateral Wilms tumor: results of the United Kingdom Children's Cancer Study Group

PURPOSE

Bilateral Wilms tumor presents the clinician with a treatment dilemma. Since 1980 most centers of the United Kingdom Children's Cancer Study Group have used a conservative surgical approach with initial biopsy followed by chemotherapy and delayed surgical resection. We assess the outcome of this treatment approach in terms of survival, and preservation of renal mass and function.

MATERIALS AND METHODS

We retrospectively analyzed the records of 71 children with bilateral Wilms tumor diagnosed between 1980 to 1995 at 17 United Kingdom Children's Cancer Study Group centers. In 57 patients conservative surgical treatment with initial biopsy was followed by chemotherapy and delayed tumor resection, while 13 underwent initial surgical resection followed by chemotherapy. One patient was excluded from study because the lesion in 1 kidney proved to be a benign cyst. Mean followup was 6 years (range 1 to 15). The percentage of renal tissue involved with tumor and preserved was estimated, and renal function at the last followup was recorded.

RESULTS

Overall survival was 69% with similar survival in the conservatively treated and initial surgical resection groups. At the last followup renal function was normal in 80% of the patients in each group. Mean preserved renal mass was 45 and 35% in the conservatively treated and initial resection groups, respectively, with a trend toward better preservation in those treated conservatively. Bilateral Wilms tumor with an unfavorable histology was associated with a poor prognosis.

CONCLUSIONS

Conservative surgical treatment of favorable histology bilateral Wilms tumor may improve the preservation of renal mass and function without impairing patient survival.

A descriptive study examining postdischarge patient needs after laser ablation and transuretheral resection of the prostate

This descriptive study identifies and describes the postdischarge experiences in two groups of patients with benign prostate hyperplasia. The two patient groups included 12 patients who underwent laser ablation and 12 patients who underwent traditional transuretheral prostatectomy. A questionnaire was developed and used to examine the postoperative experiences of the two groups after discharge. The questionnaire obtained demographic information from medical records and examined the types of assistance required at home, the need to contact health professionals, difficulties encountered after catheter removal and the amount of time until resolution of symptoms and a return to normal activities. The laser ablation group were discharged home with an indwelling catheter, and thus were required to complete additional questions regarding their experiences of going home with a catheter and leg bag. The results indicate the laser ablation group went home with an indwelling catheter and reported a higher frequency of symptom distress and technical problems in caring for the leg bag. The laser ablation group also sought more assistance from health professionals. These problems were not demonstrated in the traditional transuretheral prostatectomy group, who remained in hospital until the catheter was removed. This study demonstrates the need for further nursing research examining patient issues that occur during the postdischarge recovery phase.

High-dose recombinant human erythropoietin stimulates reticulocyte production in patients with multiple organ dysfunction syndrome

OBJECTIVE

To investigate erythropoietin (EPO) production and the erythropoietic potency of recombinant human EPO in the multiple organ dysfunction syndrome.

DESIGN

Randomized, prospective, controlled clinical trial.

MATERIALS AND METHODS

Patients received either 600 IU/kg intravenous EPO three times weekly (n = 9) or saline (control, n = 10).

MEASUREMENTS

EPO levels, circulating soluble receptors for tumor necrosis factor and interleukin-2, levels of interleukin-6 and intercellular adhesion molecule, and early peripheral blood cell progenitors.

RESULTS

EPO production in the control group remained low. Pharmacologic EPO blood levels were associated with increased reticulocyte counts compared with both controls (p < 0.04) and baseline (p < 0.006). Increased levels of soluble receptors for tumor necrosis factor in the treatment group compared with the controls did not prevent this effect. Interleukin 6 inhibited reticulocyte production.

CONCLUSION

Despite increased cytokine levels, pharmacologic EPO blood levels were associated with increased reticulocyte counts in patients with multiple organ dysfunction syndrome.