Measurement of computed tomography modulation transfer function with a novel polymethyl methacrylate phantom.

A novel phantom for measuring the 10% and 50% values of the modulation transfer function (MTF) for computed tomography scanners (CT) was investigated. The phantom was constructed by drilling rows of holes of different sizes and frequencies into a small block of polymethyl methacrylate (PMMA). The MTF at a given frequency was determined from the ratio of the range of Hounsfield units within the rows of holes at different frequencies, and the difference in Hounsfield units between air and PMMA. A MTF curve was plotted from measurements at different frequencies and the 10% and 50% MTF values were obtained from a cubic spline interpolation. The MTF results obtained with the drilled hole phantom method were compared to a conventional method - using a thin wire and Spice-CT ImageJ Plugin- and with identical acquisition and reconstruction parameters. The drilled hole phantom measured the 50% MTF with reasonable accuracy but underestimated the 10% MTF by 8.2% on average. MTF measurements were reproducible for repeated image acquisitions and with different users analysing the images, and the phantom was able to accurately measure the change in MTF when measured on images using different reconstruction kernels. The tool may find application as a cheap, easy to use method for routine QC testing of CT scanners.

The mouse and human Fli1 genes are similarly regulated by Ets factors in T cells.

Fli1 is a member of the Ets family of transcription factors and is preferentially expressed in hematopoietic cell lineages. Its expression level is linked to the pathogenesis of lupus. In this study, we identified mechanisms involved in the transcriptional regulation of the mouse and human Fli1 promoters. We show that the Fli1 promoter is upregulated by Ets factors Ets1, Ets2, Fli1 and Elf1 either alone or in combination with GATA factors, but is inhibited by Tel. In vitro binding studies show that Elf1, Tel and Fli1 in T cells bind the three Ets-binding sites in the murine Fli1 proximal promoter. We identified transcription factor-binding sites in the human Fli1 promoter region that function in T cells in a similar manner to those in the mouse promoter. Furthermore, we show similar binding of Ets factors to the endogenous mouse and human Fli1 promoters in T cells and knocking down Ets1 results in an upregulation of Fli1 expression. Together, these results suggest that the human and mouse genes are regulated similarly and that Ets1 may be important in preventing the overexpression of Fli1 in T cells. This report lays the groundwork for identifying targets for manipulating Fli1 expression as a possible therapeutic approach.

Insurance status and admission to hospital for head injuries: are we part of a two-tiered medical system?

Previous studies have shown an association between insurance status and use of resources for inpatient care. We sought to assess whether insurance status influences decisions regarding the evaluation and treatment of head injured patients in the emergency department (ED). Head injured patients were identified from ED data from 4 hospitals reporting to the Kentucky Emergency Medical Services Information System. Multiple regression analysis using admission, ED length of stay, and ED charges as outcome variables was then performed. From 216,137 ED visits there were 8,591 (4%) head injured patients identified from the database. Eliminating those with revisits, transfers to another hospital in the database, and isolated facial lacerations, there were 3,821 cases. Controlling for age, hospital, race, primary diagnosis, and indicators of severity of the injury, insurance status was significantly associated with hospital admission. Those uninsured were the least likely to be admitted (OR 0.41; 95% CI (0.31, 0.50), whereas those with public insurance had an intermediate probability (OR 0.50 95% CI (0.37, 0.68) as compared with those with private insurance. Similarly, ED charges were lower for Medicaid patients than insured patients ($880) and tended to be slightly lower for uninsured patients ($1,043) than insured patients ($1,141) (P =.001). Length of stay in the ED was shorter for publicly insured patients (179 minutes) than uninsured (186 minutes) and privately insured patients (192 minutes) (P =.001). The extent of evaluation and admission for head injured patients is associated with insurance status. This creates a dual standard of care for patients. Practitioners should work to standardize the evaluation of patients independent of paying status.

Patterns of use of emergency medical transport: a population-based study.

The objective of this study was to characterize population-based emergency medical service (EMS) use rates and examine some of the factors associated with usage of prehospital services. The design was a population-based observational study with multiple regression analysis. Transports reported by prehospital services to the Kentucky Emergency Medical Services Information System from Kentucky counties in which all EMS units submit computerized data was the data source. There were 102,321 emergent transports reported. The overall rate of use of EMS transports was 51.7 +/- 24.1/1,000/year, but the rate varied between different communities (range 11 to 139/1,000/year). Rate of use was highest in those older than 65 (178.5 +/- 84.2/1,000/year), with the rate increasing exponentially with increasing age in this age group. Reasons for transport were age dependent. There was an association between increasing poverty level and use of EMS. In addition, the absence of 911 service (odds ratio [OR] 1.18, 95% confidence interval [CI; 1.14,1.22]) and the absence of a hospital in the county (OR 1.27, 95% CI [1.24,1.30]) were also associated with increasing rates of ambulance use. Rates of use of EMS are most dependent on age and cause, but use is also correlated with increasing levels of poverty. Wide variations in use between communities suggests that point estimates using one community may over- or underestimate EMS usage.

Non-specific effect of naltrexone on ethanol consumption in social drinkers.

RATIONALE: Clinical studies have shown that the opioid antagonist naltrexone is effective in the treatment of alcoholism. However, the mechanism by which it produces this effect is not understood. OBJECTIVE: This study was designed to investigate the effect of acute naltrexone on consumption of ethanol in healthy, non-problem social drinkers. METHODS: Subjects (n=24) participated in an eight-session, within-subject, placebo-controlled choice procedure which measured ethanol preference and consumption. The procedure consisted of two blocks of four sessions in which subjects received either naltrexone (50 mg oral) or placebo 1 h before consuming an ethanol or placebo beverage. On the first two sessions of each block, subjects received a color-coded beverage containing ethanol (0.75 g/kg) or placebo, in five equal portions at 15-min intervals. On the next two sessions of each block, subjects chose which beverage they preferred (i.e., placebo or ethanol) and how much they wished to take, in unit doses (placebo or ethanol 0.15 g/kg/dose). The primary behavioral measures were (1) the number of times subjects chose ethanol over placebo, and (2) the number of doses they consumed. Subjects rated their mood states and subjective drug effects at regular intervals during each session. RESULTS: Naltrexone did not alter the frequency of ethanol (versus placebo) choice. Although naltrexone did decrease the total number of ethanol doses subjects took (mean 2.7 doses after naltrexone; 3.4 doses after placebo), it also decreased the number of placebo "doses" subjects took on sessions when they chose the placebo beverage (mean 1.6 placebo doses after naltrexone; 2.8 doses after placebo). Ethanol produced its prototypic subjective effects (e.g., increased ratings of "feel drug", "like drug" and "high"), and these effects were not altered by naltrexone. Naltrexone produced mild sedative-like effects, and several subjects reported adverse effects such as nausea. CONCLUSIONS: These findings show that naltrexone reduces ethanol consumption in healthy volunteers, as it does in alcoholics. However, this reduction was not specific to alcohol; subjects also consumed less of a non-alcoholic, placebo beverage. These findings suggest that naltrexone may reduce alcohol consumption by a non-specific mechanism.

Spectroscopic studies of the molecular imprinting self-assembly process.

A method for the rapid estimation of the extent of complex formation in molecular imprinting prepolymerization mixtures is described. By the use of a UV spectroscopy titration procedure, apparent binding constants for such self-assembly processes have been obtained. This method was used for comparison of the interactions between a dipeptide template (N-acetyl-L-phenylalaninyl-L-tryptophanyl methyl ester) and the functional monomer methacrylic acid, and the monomer analogues acetic acid and trifluoroacetic acid. The importance of template-monomer association during the molecular imprinting prepolymerization phase is discussed with respect to the systems studied.

Critical care of medical and surgical patients in the ED: length of stay and initiation of intensive care procedures.

Little is known about the extent of critical care delivered to patients in the emergency department (ED) and its impact on ED lengths of stay or patient outcomes. The purpose of this study was to characterize the timing of care for critically ill patients, both medical and surgical, in the ED. The design was a retrospective review. The setting was a university teaching hospital. The subjects were ED patients subsequently admitted to a medical or surgical intensive care unit (ICU). The average length of stay in the ED was 367 minutes. Thirty percent of patients were boarded in the ED because of lack of beds in the ICU. Stabilization procedures were performed on 45 (27%) patients, on average 102 minutes after ED admission. Monitoring procedures were performed on 35 (21%), on average 170 minutes after ED admission. There were no significant differences in length of stay, use, and timing of critical procedures in medical and surgical patients. Critically ill patients represent a significant portion of ED patients and may remain in the ED for prolonged periods of time. One of the major contributors to these prolonged stays are lack of beds. Both resuscitative and monitoring procedures are often performed in the ED setting for all types of critical patients. The timing of these procedures indicates that they are performed when necessary for patient care regardless of ED or ICU setting. Thus, ICU care is often initiated and maintained in the ED setting. EDs must be staffed adequately with appropriately trained personnel to care for these patients.

Headache in the emergency department: importance of history in identifying secondary etiologies.

Headache is a common emergency department complaint and has a broad differential diagnosis. Most commonly the headache is without serious underlying cause, but occasionally can be the manifestation of a more catastrophic illness. History may be the most important aspect in the evaluation of headache patients and careful attention to historical clues or atypical symptoms may point to a diagnosis. We present a patient with a first-time headache, which was ultimately found to be secondary to a carotid cavernous fistula. Historical features that require a more aggressive work-up of headache are discussed.

Population density, automated external defibrillator use, and survival in rural cardiac arrest.

OBJECTIVE: To determine whether population density is an independent predictor of survival from out-of-hospital cardiac arrest managed by basic life support (BLS) services using automated external defibrillators (AEDs). METHODS: A retrospective, observational study in Kentucky of 34 BLS services covering 22 counties during the years 1992 to 1994 who used AEDs to treat patients who had out-of-hospital cardiac arrests. RESULTS: Of 311 patients who had out-of-hospital cardiac arrests, 110 (35%) were defibrillated, 46 (15%) were resuscitated to hospital admission, and 19 (6%) survived to hospital discharge. Univariate predictors for survival to hospital discharge were emergency medical services response interval (from call receipt to ambulance arrival) < 8 minutes, defibrillation by the AED, initial rhythm of ventricular fibrillation or ventricular tachycardia (VF/VT), and population density > 100/square mile (sq mi) for the BLS service area (p < 0.001). A forced logistic regression model of survival to hospital discharge, using these 4 factors plus the presence of a witnessed arrest or bystander CPR, demonstrated that population density > 100/sq mi was highly significant (OR 9.4, 95% CI: 1.7 to 51.4, p < 0.01). Stepwise logistic regression models with combinations of these 6 factors found that survival to hospital discharge was best predicted by an initial rhythm of VF/VT (p = 0.004) and population density > 100/sq mi (p = 0.011). CONCLUSIONS: Population density is strongly associated with survival from out-of-hospital cardiac arrest. BLS services within areas with population densities < or = 100/sq mi sustained little benefit from the addition of AEDs to their treatment of patients who had out-of-hospital cardiac arrests.

Competitive flow injection enzyme immunoassay for steroids using a post-column reaction technique.

Two types of flexible, sensitive and rapid competitive flow injection enzyme immunoassay were developed and evaluated for their potential use in the bioanalysis of steroids. Instead of the more typical approach where the signal is generated from antibody-bound hapten-enzyme conjugate, the non-bound fraction passing through the affinity column was allowed to react with an enzyme substrate from a merging channel in a post-column reaction system. The enzyme product (p-aminophenol or 4-methyl umbelliferol) was amperometrically or fluorometrically detected. Several parameters known to affect signal generation in the immunoassay were evaluated, including flow rate through the affinity column and through the reaction coil, the length of the reaction coil and of the affinity column. In the pre-incubation approach, where samples were mixed with enzyme conjugate and antibodies before injection, a sample throughput as high as 20 h(-1) was possible. The signal precision was about 1% (RSD) for cortisol (0.6-80 pmol) and 2% (RSD) for budesonide (0.02-12.5 pmol). In the displacement assay for cortisol, enzyme-labelled analyte was displaced from the affinity column when the sample was injected into the flow. A standard curve was obtained with a signal precision of 4-20% for 12.5-1250 pmol injected. The same instrumental set-up was used in both types of immunoassay, and thus a highly flexible system was obtained. A simple replacement of the affinity column from protein G in the pre-incubation approach to a column containing primary antibodies in the displacement assay was needed.

The Kentucky Emergency Medical Services Information System: current progress and future goals.

The Kentucky Emergency Medical Services Information System was formed in 1993 to establish a centralized registry of prehospital and emergency department data. These data can aid individual providers in planning and providing patient services and state planners in systems development and disease surveillance. This article seeks to provide an overview of the system for providers of acute care services in Kentucky, its current capabilities and future goals.

Pediatric prehospital care: epidemiology of use in a predominantly rural state.

The objective of this study was to analyze, by retrospective review, the pediatric population utilizing emergency medical services (EMS) throughout Kentucky, with particular emphasis on differences between urban and rural areas. The source of the data used was from all prehospital runs in children less than 17 years of age reported in Kentucky in a computerized database to the state EMS branch. There were no interventions. We found that pediatric calls were more frequent in adolescents than younger children. Trauma was more frequent in older children and in rural settings and accounted for nearly 50% of all calls. Motor vehicle accidents were the most frequent cause of traumatic injuries. Run times were prolonged in the rural setting, but this was a reflection of transport rather than scene times. The use of basic life support (BLS) and advanced life support (ALS) procedures was dependent on the patient's age and the level of care of the provider. ALS procedures were infrequently performed, especially in younger patients, although the performance of these procedures did not prolong scene times. We conclude that educational initiatives for pediatric care in the prehospital setting should include assessment and stabilization of children, including appropriate procedures, both for ALS and BLS providers. Prehospital data should be linked with police reports and emergency department data to provide means of assessing the impact of prehospital services on outcome in pediatric patients.

Pediatric firearm-related fatalities. Not just an urban problem.

OBJECTIVE: To examine medical and demographic factors associated with the firearm-related deaths among children in Kentucky. DESIGN: Retrospective review and multiple regression analysis. DATA SOURCE: All firearm-related deaths among children younger than 20 years reported to the Kentucky Office of Vital Statistics, Frankfort, from 1988 to 1993. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: All 320 pediatric firearm-related deaths that occurred in Kentucky from 1988 to 1993 were analyzed. Death rates were calculated for each county in the state. While the overall death rate from firearms was not significantly different between African-American and white children (relative risk [RR], 1.39; 95% confidence interval [CI], 0.98-1.98), the pattern of the types of events was markedly different. African American children were much more likely to have been involved in a homicide; suicides were more frequent in white children. Multiple Poisson regression analysis, controlling for age, race, and gender, identified only 1 variable that was significantly associated with deaths due to firearms. Children in rural Kentucky were at significantly more risk for a firearm-related death than children in urban areas (RR, 1.26; 95% CI, 1.01-1.62) even after controlling for medical system variables (availability of a hospital with 24-hour emergency services, availability of prehospital advanced life support, and availability of 911 service). CONCLUSIONS: Children in rural areas of Kentucky are at an increased risk for firearm-related mortality. Prevention and intervention programs that focus only on urban areas may not produce optimum results in the Kentucky setting. Further research is needed to determine factors that are important in rural areas so that interventions specific to them can be planned.

Factors associated with the higher traumatic death rate among rural children.

STUDY OBJECTIVE: To examine medical and demographic factors associated with traumatic deaths among children in Kentucky. METHODS: This was a retrospective review and multiple regression analysis of all deaths in children younger than 18 years reported to the Kentucky Office of Vital Statistics from 1988 to 1992. RESULTS: All 1,024 pediatric trauma deaths that occurred from 1988 to 1992 were analyzed. Death rates were calculated for each type of trauma for each county in the state. Motor vehicle accidents accounted for most of the pediatric deaths, but this finding was markedly age dependent. Death rates were higher in rural Kentucky for all forms of trauma and were highest in the Appalachian region. Multiple Poisson regression analysis identified variables associated with the traumatic pediatric death rates. Rural setting was associated with higher traumatic death rates, whereas the availability of a hospital with 24-hour emergency services in the county and the presence of advanced life support prehospital care were associated with lower death rates. Children in Appalachia were at an increased risk compared with other Kentucky children, even when we controlled for the rural nature of Appalachia. CONCLUSION: Demographic and medical system factors are associated with traumatic death rates in Kentucky children. Access to care and advanced prehospital support were both significantly associated with lower pediatric death rates. Increased access to quality care and training of prehospital providers in advanced life support should be priorities in the planning of trauma systems for this state.

Development of a statewide trauma system: classification of levels of care available to injured patients.

OBJECTIVE: To categorize the level of care offered in emergency settings at acute care hospitals in Kentucky. DESIGN: Survey mailed to all hospitals in the state. MEASUREMENTS/MAIN RESULTS: Hospital capabilities for both adult and pediatric patients were assessed by strict adherence to a set of preset objective requirements and by a subjective review of the resources available to the acutely injured patient, based on the responses to a mailed questionnaire. There are three level 1 and nine level 2 hospitals available to adults and two level 1 and seven level 2 hospitals available to children in Kentucky. Thirty-five counties are without an acute care hospital. Objective- and subjective-based classification were discordant in approximately 25% of hospitals. Current referral patterns reflect this categorization, but referral is most often directly to level 1 centers. CONCLUSIONS: We have established a set of criteria to categorize the level of care acutely available to injured patients in Kentucky which can be simply implemented. In developing statewide systems of care, strict adherence to preset criteria may not accurately reflect the true resources available. With the lack of a planned and organized system, current referral patterns reflect transfer of patients directly to level 1 centers, which may result in overtriage and underutilization of level 2 or level 3 hospitals.

Compliance with antimalarial chemoprophylaxis and the subsequent development of malaria: a matched case-control study.

To determine if there is a difference in compliance with antimalarial chemoprophylaxis between febrile travelers with and without malaria, 157 patients with malaria, a history of fever, and recent travel to a malaria-endemic area were compared with 157 matched controls. Antimalarial prophylaxis had been taken by 48% of all patients. Chemoprophylaxis use was correlated with region and purpose of travel. Cases were less likely to have taken prophylaxis (53%) than controls (76%) (odds ratio = 0.35, confidence interval = 0.27, 0.73), even after controlling for region of travel, purpose of travel, and previous exposure to malaria. Chemoprophylaxis was effective in reducing malaria risk. Travel agents and health practitioners should provide all travelers to malaria-endemic areas with adequate information about chemoprophylaxis and its importance.

Diagnosis of malaria in the febrile traveler.

To determine if clinical presentation can be used for predicting malaria infection in febrile patients with recent travel to a malaria-endemic area, 157 patients with malaria, a history of fever, and recent travel to a malaria-endemic area were compared with 157 matched controls in case-control study. Fever pattern, symptom duration, temperature, splenomegaly, and platelet count were correlated with malaria infection. These criteria, however, either singly or in combination, had low sensitivity for accurately identifying patients with malaria. Because no criterion could accurately predict the presence of malaria, it is concluded that microscopic examinations of blood for malaria parasites should be done in all symptomatic patients with a history of travel to a malaria-endemic area.

Hazards to children riding in the back of pickup trucks.

PURPOSE: The goal of this study was to identify the spectrum of injuries and risks associated with children riding in the back of pickup trucks and stimulate the medical and legislative community to adopt laws aimed at protective interventions for this type of travel. METHODS: Patients were identified and data collected retrospectively from trauma registries at the two major university urban trauma centers in Kentucky. RESULTS: From 1988 to 1993, 33 patients less than 18 years old were ejected from the back of pickup trucks. The majority were males older than 10 years. Injuries occurred predominantly during summer, in early evening, and in rural areas. Eleven patients were ejected during a collision, 19 were ejected from a moving truck, and 3 fell from a stationary truck. The head was the predominant organ injured. The average ISS score was 12.0 (+/- 7.5). The length of stay in the hospital varied from 1 to 84 days with 13 patients requiring intensive care. Three patients died and 3 required rehabilitation therapy. CONCLUSION: We conclude that (1) Children riding in pickup truck beds are at serious risk of being ejected from the vehicle; (2) children are frequently ejected from truck beds in non-crash events; and (3) continued attention should be directed to enacting stronger legislation limiting passenger transport in pickup truck beds.