Gradient coil and radiofrequency induced heating of orthopaedic implants in MRI: influencing factors.

Patients with implanted orthopaedic devices represent a growing number of subjects undergoing magnetic resonance imaging (MRI) scans each year. MRI safety labelling is required for all implants under the EU Medical Device Regulations to ensure regulatory compliance, with each device assessed through standardised testing procedures. In this paper, we employ parametric studies to assess a range of clinically relevant factors that cause tissue heating, performing simulations with both radiofrequency (RF) and gradient coil (GC) switching fields, the latter of which is often overlooked in the literature. A series of 'worst-case' scenarios for both types of excitation field is discussed. In the case of GC fields, large volume implants and large plate areas with the field orientated perpendicular to the plane cause the highest heating levels, along with sequences with high rates of field switching. Implant heating from RF fields is driven primarily from the 'antenna effect', with thin, linear implants of resonant length resulting in the highest temperature rises. In this work, we show that simplifications may be made to the field sequence and in some cases the device geometry without significantly compromising the accuracy of the simulation results, enabling the possibility for generic estimates of the implant heating for orthopaedic device manufacturers and opportunities to simplify the safety compliance process.

Simultaneous dynamic electrical and structural measurements of functional materials.

A new materials characterization system developed at the XMaS beamline, located at the European Synchrotron Radiation Facility in France, is presented. We show that this new capability allows to measure the atomic structural evolution (crystallography) of piezoelectric materials whilst simultaneously measuring the overall strain characteristics and electrical response to dynamically (ac) applied external stimuli.

Aztreonam for inhalation solution (AZLI) in patients with cystic fibrosis, mild lung impairment, and P. aeruginosa.

BACKGROUND: Previous aztreonam for inhalation solution (AZLI) studies included patients with cystic fibrosis, Pseudomonas aeruginosa (PA) airway infection, and forced expiratory volume in 1s (FEV(1)) 25% to 75% predicted. This double-blind, multicenter, randomized, placebo-controlled trial enrolled patients (≥6 years) with FEV(1)>75% predicted. METHODS: AZLI 75 mg (n=76) or placebo (n=81) was administered 3-times daily for 28days with a 14-day follow-up. RESULTS: Day 28 treatment effects were 1.8points for CFQ-R-Respiratory Symptoms Scale (95%CI: -2.8, 6.4; p=0.443; primary endpoint); -1.2 for log(10) sputum PA colony-forming units (p=0.016; favoring AZLI), and 2.7% for relative FEV(1)% predicted (p=0.021; favoring AZLI). Treatment effects favoring AZLI were larger for patients with baseline FEV(1) <90% predicted compared to ≥90% predicted. AZLI was well-tolerated. CONCLUSIONS: Effects on respiratory symptoms were modest; however, FEV(1) improvements and bacterial density reductions support a possible role for AZLI in these relatively healthy patients.

Electronic texture of the thermoelectric oxide Na0.75CoO2.

From 59Co and 23Na NMR, we demonstrate the impact of the Na+ vacancy ordering on the cobalt electronic states in Na0.75CoO2: at long time scales, there is neither a disproportionation into 75% Co3+ and 25% Co4+ states, nor a mixed-valence metal with a uniform Co3.25+ state. Instead, the system adopts an intermediate configuration in which 30% of the lattice sites form an ordered pattern of localized Co3+ states. Above 180 K, an anomalous mobility of specific Na+ sites is found to coexist with this electronic texture, suggesting that the formation of the latter may contribute to stabilizing the Na+ ordering. Control of the ion doping in these materials thus appears to be crucial for fine-tuning of their thermoelectric properties.

Flight activity of the blowflies, Calliphora vomitoria and Lucilia sericata, in the dark.

Many species of insects are able to fly at night or in very low light intensities. The question of whether calliphorid blowflies are also able to do this to locate a corpse and oviposit nocturnally is of considerable forensic importance. However, to date studies of this behaviour have been contradictory. Here, the activity and number of Calliphora vomitoria L. and Lucilia sericata (Meigen) (Diptera: Calliphoridae) caught on sticky-traps were examined in a slow-speed wind tunnel, at different intensities of artificial light. The traps were either unbaited or baited-with liver. The number of both species caught, decreased incrementally as light intensity was reduced. While the responses of the two species were broadly similar, L. sericata were significantly more active than C. vomitoria, especially at higher light intensities. The number of flies of both species that were caught was higher in the presence of liver bait, but the presence of the liver bait did not change the shape of the relationship between catch and light intensity. Hence, light intensity acts as an independent exogenous stimulus for activity and although liver volatiles increase activity levels, they are not necessary as an activation stimulus. Comparison of the numbers caught in small or large enclosures suggests that any flies caught in darkness probably alighted on the trap by chance and that in darkness, while flies may be activated by carrion odours, they do not appear to be able to navigate effectively to the source of that odour. The results presented here suggest that in darkness, the probability of oriented flight leading to oviposition on a corpse by either species, is relatively low.

Good prognosis cytogenetics in B-cell chronic lymphocytic leukemia is associated in vitro with low susceptibility to apoptosis and enhanced immunogenicity.

Chromosomal abnormalities in B-cell chronic lymphocytic leukemia (B-CLL) have been shown to correlate with prognosis. Little is known about the relationship between chromosomal abnormalities and biological behavior of B-CLL cells in vitro. The present study was designed to explore the impact of chromosomal abnormalities determined by interphase fluorescence in situ hybridization (FISH) on the in vitro survival and immunogenicity of B-CLL. Considerable heterogeneity was noted in the in vitro survival and expression of costimulatory, adhesion, and antigen-presenting molecules by B-CLL cells. Spontaneous apoptosis of B-CLL cells in vitro was significantly lower in samples with good prognosis cytogenetics when compared to samples with poor prognosis cytogenetics. In contrast, B-CLL cells from samples with good prognosis cytogenetics exhibited higher basal expression of molecules involved in costimulation, cellular adhesion, and antigen presentation, and induced significantly more T-cell proliferation in mixed lymphocyte cultures. We conclude that chromosomal aberrations of B-CLL cells correlate with the in vitro biological behavior of B-CLL. Our data indicate that good prognosis cytogenetics correlates with less spontaneous apoptosis but greater in vitro immunogenicity. These findings could have significant implications on the design of future therapeutic approaches in patients with CLL, and the likelihood of response based on cytogenetics.

Impact of the life skills training curriculum on middle school students tobacco use in Marion County, Indiana, 1997-2000.

Evaluation of school-based tobacco prevention and control programs have yielded mixed results. This study assessed the impact of the Life Skills Training curriculum on Marion County, Ind., middle school students' knowledge, attitudes, and ability to make good lifestyle decisions. From 1997 to 2000, students in grades six to eight in the study schools received the Life Skills Training curriculum. Survey data (n = 1,598) were used to compare tobacco use behavior, attitudes, and knowledge of those exposed with those not exposed to the program. Of the students surveyed, 12.5% were currently smoking. There were significantly fewer current smokers, and more students exposed to the program indicated they intended to stay smoke-free. Fewer of those participating in the program "hung out" with smokers and more said they could easily refuse a cigarette if offered one. Students completing the Life Skills Training curriculum were more knowledgeable about the health effects of smoking. Program effects were different for male and female students as well as for White and Black students.

Preparticipation Screening of Athletic Officials: SEC Football Referees at Risk.

UNLABELLED: Although preparticipation screening for athletes is commonplace, few studies have addressed the issue for those officiating at games. OBJECTIVES: To review current data on physiologic stress on sports officials, to obtain prevalence data on health parameters for football officials, and to determine the outcomes when screening criteria are applied in preseason exams. METHODS: A protocol was established using health history questionnaires and physical exams with laboratory screening to assess the health of all football officials working in the Southeastern Conference (SEC) from 1997 to 2000. The main outcome measure was the prevalence of cardiac risk factors as determined by American College of Sports Medicine guidelines. RESULTS: Initial screening of 102 football officials revealed that 10.1% of SEC referees had elevated systolic blood pressure, 13.9% had elevated diastolic blood pressure, and 3.8% had resting tachycardia. Average body mass index (BMI) was 28.6 kg/m2, with 87.3% having a BMI that exceeded 25 (overweight). About one-third (31.6%) had a BMI greater than 30 (obese). Total fasting cholesterol exceeded 200 mg/dL in 44.2%, HDL levels were below 35 mg/dL in 34.3%, and LDL levels were above 120 mg/dL in 62.3%. Compared with age-adjusted national data, there were more overweight and more obese officials, but they had lower systolic and diastolic blood pressures and lower mean total cholesterol levels. Using the Framingham Study prediction model to estimate coronary heart disease (CHD) risk, analysis revealed that referees had a lower risk than the national 10-year CHD risk but a higher risk compared with that of the low-risk population. CONCLUSIONS: These data reveal a greater need for graded exercise testing. The higher rates of obesity among officials will promote further screening for CHD risk factors.

A randomized trial of a brief intervention to increase fruit and vegetable intake: a replication study among callers to the CIS.

BACKGROUND: Results are reported from a large randomized trial designed to increase fruit and vegetable consumption among callers to the National Cancer Institute's Cancer Information Service (CIS) (n = 1,717). METHODS: CIS callers assigned to the intervention group (n = 861) received a brief proactive educational intervention over the telephone at the end of usual service, with two follow-up mailouts. Key educational messages and print material derived from the NCI 5 A Day for Better Health program were provided to intervention participants. Participants were interviewed by telephone at 4 weeks (n = 1,307), 4 months (n = 1,180), and 12 months for follow-up (n = 1,016). RESULTS: Results obtained from a single-item measure of fruit and vegetable consumption indicate a significant intervention effect of 0.88 servings per day at 4 weeks follow-up (P < 0.001), 0.63 servings per day at 4 months follow-up (P < 0.001), and 0.43 servings per day at 12 months follow-up (P < 0.001). Using a 7-item food frequency measure, an intervention effect of 0.63 servings per day was obtained at 4 weeks follow-up (P < 0.001), compared with 0.39 servings per day at 4 months follow-up (P = 0.002) and 0.44 servings per day at 12 months follow-up (P = 0.002). A 24-h recall assessment included in the 4-month interviews also yielded a significant intervention effect of 0.67 servings per day (P = 0.015). The vast majority of callers (90%) endorsed the strategy of providing 5 A Day information proactively within the CIS. CONCLUSIONS: This brief educational intervention was associated with higher levels of self-reported fruit and vegetable intake at both short- and long-term follow-up. Additional research is recommended to test this or a similar intervention in diverse populations.

Corticosteroids in advanced cancer.

Despite the fact that there are only a few controlled trials demonstrating the benefits associated with the use of corticosteroids in specific situations, these agents are administered frequently to patients with advanced cancer. Corticosteroids may be used alone or as adjuvants in combination with other palliative or antineoplastic treatments. For example, corticosteroids may help prevent nausea, vomiting, and hypersensitivity reactions to treatment with chemotherapy or radiation. They are also commonly used as appetite stimulants in patients with advanced cancer. In the adjuvant setting, corticosteroids help to alleviate pain in advanced cancer patients, including specific situations such as back pain related to epidural compression. This article reviews the evidence supporting the use of corticosteroids in a broad range of situations seen in patients with advanced cancer.

Setting rates for Medicaid managed behavioral health care: lessons learned.

This paper reviews Tennessee's experience setting, monitoring, and updating capitation rates for Medicaid managed behavioral health care, and draws lessons from those experiences for other states. Our review of assumptions about four components of Tennessee's rate-setting process--data, benefit design, savings expectations, and processes for monitoring and updating rates--suggests that the initial rate established by Tennessee was inadequate, and its inadequacy resulted primarily from the way available information was used to set the rate, rather than from the method of rate setting selected. Tennessee's experiences illustrate how difficult rate setting is and illuminate several key lessons about the rate-setting process.

Renal transplantation in cats.

Feline renal transplantation can offer long-term survival with a normal quality of life for cats with renal failure. However, it is important to remember that renal transplantation is a treatment option and not a cure. Renal transplantation is never performed on an emergency basis or prophylactically. Feline renal transplantation requires special microvascular instruments and an operating microscope. Careful patient selection and perioperative monitoring have improved the success rate. The new microemulsified form of cyclosporine is recommended for immunosuppression. As survival times have steadily improved, long-term complications, such as diabetes and neoplasia, are now being recognized.

Perils of pioneering: monitoring Medicaid managed care.

This article reviews Federal and State oversight of section 1115 Medicaid managed care demonstrations in Hawaii, Oklahoma, Rhode Island, and Tennessee from 1994 to 1998. Under Medicaid managed care, the Federal Government and States have had to shift their focus and resources into oversight functions that barely existed in fee-for-service (FFS) Medicaid. We find that managed care monitoring was slow to begin and not always adequate in these demonstrations. While State and Federal monitoring have improved over time, monitoring is not yet at the point of ensuring access and quality.

Management of hypertension controls postoperative neurologic disorders after renal transplantation in cats.

OBJECTIVES: To determine the prevalence and describe the management of hypertension and central nervous system (CNS) complications after renal transplantation in cats. We also compared the prevalence of CNS complications between cats monitored and treated for postoperative hypertension and a previously described, historical control group of cats not monitored or treated for postoperative hypertension. STUDY DESIGN: Retrospective clinical study. ANIMALS OR SAMPLE POPULATION: A total of 34 client-owned cats that received renal allografts for the treatment of end-stage renal failure. METHODS: Medical records were reviewed. Data obtained included preoperative and postoperative systolic blood pressures, antihypertensive therapy, response to treatment, neurologic signs, and clinical outcome. The results were compared with a historical control group of feline renal allograft recipients that were neither monitored nor treated for postoperative hypertension. RESULTS: Severe postoperative hypertension occurred in 21 of 34 of cats. Hypertension was treated in all 21 cats with subcutaneously administered hydralazine which reduced systolic blood pressure to less than 170 mm Hg in 15 minutes in 20 of 21 cats; hydralazine produced hypotension in one cat and failed to control hypertension in 1 cat. After transplantation, seizures were observed in one cat and other neurologic complications (stupor, ataxia, and central blindness) were observed in three cats. The prevalence of seizures and neurologic complication-related deaths after transplantation was significantly reduced with treatment of postoperative hypertension. CONCLUSIONS AND CLINICAL RELEVANCE: Hypertension is a major contributing factor to postoperative seizure activity after renal transplantation in cats; treatment of hypertension reduces the frequency of neurologic complications.

Outcome of surgical versus medical treatment of dogs with beta cell neoplasia: 39 cases (1990-1997).

OBJECTIVE: To compare outcome of surgical versus medical treatment of dogs with beta cell neoplasia. DESIGN: Retrospective study. ANIMALS: 39 dogs with clinical signs of hypoglycemia and serum glucose and insulin concentrations consistent with a diagnosis of beta cell neoplasia. PROCEDURE: Information on signalment; clinical history; physical examination findings; results of CBC, serum biochemical analyses, and urinalysis; serum glucose and insulin concentrations; results of thoracic radiography and abdominal ultrasonography; treatment and treatment complications; survival time; and cause of death were obtained from medical records. RESULTS: 26 dogs underwent exploratory celiotomy and partial pancreatectomy; 13 dogs were treated medically (i.e., dietary change and prednisone). Median survival time was significantly longer for dogs treated surgically than for dogs treated medically. Significant differences were not found in mean age, body weight, duration of clinical signs prior to diagnosis, serum glucose and insulin concentration, or results of other serum biochemical tests between dogs treated surgically and dogs treated medically; also, there was no significant correlation between any of these parameters and survival time for either group of dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that exploratory celiotomy and partial pancreatectomy are indicated once a tentative diagnosis of beta cell neoplasia is established in dogs.

Web site design and development issues: the Washington State Breast and Cervical Health Program Web Site Demonstration Project.

PURPOSE/OBJECTIVES: To explore the development of a customized Web site to assist Breast and Cervical Health Program (BCHP) outreach staff in a community screening program and to evaluate the Internet knowledge and access issues and barriers of outreach staff during a two-year period using the Web site. DESIGN: Knowledge, access issues and barriers, and descriptive questionnaires. SETTINGS: Comprehensive cancer center in Seattle, WA, workshops, and presentations around the state. SAMPLE: BCHP outreach workers, screening coordinators, and almost exclusively public health nurses from regional health districts and program-contracted clinics. METHOD: Web site development was based on continuous input from sample. Detailed descriptions of computer and Internet resources and opinions about the use and usefulness of the BCHP Web site came from a 1996 evaluation and 1998 follow-up conducted using mailed and online Web questionnaires. "Hits" to the Web site were monitored monthly. MAIN RESEARCH VARIABLES: Computer and Internet resources were used along with monthly Web site traffic and opinions about the use and usefulness of the BCHP Web site in the outreach program. FINDINGS: Use of the BCHP Web site has risen steadily over two years to reach a stable plateau. User evaluations show a marked increase in the adoption of the Internet as a working tool. Users believe the Internet is becoming increasingly important to their work. More training and familiarization with the Web is needed. CONCLUSIONS: The Web is an efficient medium for improving communication and providing easy access to resources within the BCHP program. IMPLICATIONS FOR NURSING PRACTICE: Public health programs with meager resources can benefit from the relatively inexpensive use of customized and versatile Web sites.

Ionized and total serum magnesium concentrations in feline renal transplant recipients.

OBJECTIVE: To measure the blood concentrations of total and ionized serum magnesium in feline renal transplant recipients and to determine if there was a correlation between these concentrations and the development of neurological disorders after renal transplantation. STUDY DESIGN: Prospective clinical study. ANIMALS: Fourteen client-owned cats undergoing renal transplantation as a treatment for renal failure. Ten healthy adult cats were used to establish normal electrolyte concentrations. METHODS: Total and ionized serum magnesium as well as potassium and ionized calcium concentrations were measured in 14 renal transplant recipients at five intervals: preoperatively; immediately postoperatively; and 24, 48, and 120 hours postoperatively. The mean values from all 14 cats over each time interval were compared with the normal range. The serum concentration of these electrolytes, particularly magnesium, was evaluated in relation to the occurrence of neurological complications. RESULTS: Ninety-four percent of all ionized serum magnesium concentrations measured in clinical patients were below normal. Ninety percent of all total serum magnesium concentrations were within the normal range, and no cats had abnormally low total serum magnesium concentrations at any time. All clinical patients were hypocalcemic at all intervals. Sixty-six percent of all serum potassium concentrations were below normal. One cat in the study group experienced neurological problems, including seizures, in the immediate postoperative period. The signs appeared to be related to hypertension and responded to appropriate therapy. All electrolyte concentrations in this cat, including ionized magnesium, were within the same range of values as other clinical patients. CONCLUSIONS: Ionized serum magnesium concentrations are decreased in feline renal transplant recipients in the perioperative period; however, hypomagnesemia would not appear to be directly related to the development of neurological disorders. None of the study patients were hypomagnesemic when total serum magnesium concentrations were measured over the same intervals. In addition, ionized serum calcium concentrations and serum potassium concentrations are below normal in the perioperative period. CLINICAL SIGNIFICANCE: The specific clinical significance of these abnormalities is unknown. It is possible that the profound weakness and depression that is commonly seen in feline renal transplant recipients in the immediate postoperative period may be improved by supplementation with these electrolytes. Further work is needed to understand the implications of these abnormalities.

A validation study using the case-control method of the nursing diagnosis high risk for aspiration.

PURPOSE: To develop further the nursing diagnosis risk for aspiration by determining risk factors present in patients who aspirated. METHODS: The case-control design was used to compare cases (n = 131) and controls (n = 206) on past and present exposures thought to be risk factors for aspiration. Data were analyzed using univariate and multiple logistic regression. FINDINGS: The following risk factors were statistically significant and comprise the final model: altered level of consciousness, metoclopramide (known to accelerate gastric emptying), vomiting, seizures, and unable to change own position. CONCLUSIONS: The risk factors of altered level of consciousness and delayed gastric emptying are currently included in the NANDA taxonomy for the nursing diagnosis risk for aspiration. These risk factors are not included in the taxonomy: vomiting, seizures, and unable to change own position. Results of the study have been submitted to the Diagnosis Review Committee for consideration to further develop this diagnosis.

Immunostimulatory oligodeoxynucleotides containing the CpG motif are effective as immune adjuvants in tumor antigen immunization.

Recent advances in our understanding of the immune response are allowing for the logical design of new approaches to cancer immunization. One area of interest is the development of new immune adjuvants. Immunostimulatory oligodeoxynucleotides containing the CpG motif (CpG ODN) can induce production of a wide variety of cytokines and activate B cells, monocytes, dendritic cells, and NK cells. Using the 38C13 B cell lymphoma model, we assessed whether CpG ODN can function as immune adjuvants in tumor antigen immunization. The idiotype served as the tumor antigen. Select CpG ODN were as effective as complete Freund's adjuvant at inducing an antigen-specific antibody response but were associated with less toxicity. These CpG ODN induced a higher titer of antigen-specific IgG2a than did complete Freund's adjuvant, suggesting an enhanced TH1 response. Mice immunized with CpG ODN as an adjuvant were protected from tumor challenge to a degree similar to that seen in mice immunized with complete Freund's adjuvant. We conclude that CpG ODN are effective as immune adjuvants and are attractive as part of a tumor immunization strategy.