Shortened left ventricular filling time in dilated cardiomyopathy: additional effects on heart rate variability?

OBJECTIVE--To assess possible mechanical influences underlying the reduced heart rate variability in patients with dilated cardiomyopathy. DESIGN--Comparison of standard non-spectral indices of heart rate variability with echocardiographic Doppler measures of left ventricular function in patients and normal controls. PATIENTS--20 patients with dilated cardiomyopathy and 15 normal subjects of similar ages were studied. METHODS--Standard non-spectral indices of heart rate variability were measured over 24 hours. These were correlated with left ventricular cavity size, shortening fraction, and isovolumic relaxation time measured by M mode echocardiography, and the duration of functional mitral regurgitation and left ventricular filling time assessed by continuous wave Doppler. RESULTS--Mean RR interval and estimates of short term variability (root mean square difference of successive RR intervals, proportion of adjacent RR intervals > 50 ms different, and SD indices) were not different from normal. The overall mean (SD) of the RR interval (65 (35)), and SD of five minute mean RR intervals (55 (30)), however, were reduced compared with normal values (115 (40) and 105 (45); p < 0.01 for both). Neither correlated with left ventricular cavity size or shortening fraction, but both were strongly related to left ventricular filling time (coefficient of variation, r = 0.82 and r = 0.81 respectively). Correlation persisted when the SD was corrected for RR interval (r = 0.69) although this correlation was not found in the controls. In individual patients, the difference between RR interval at the time of echo and minimum value during the 24 hours, a measure of ability to increase heart rate, also correlated closely with filling time (r = 0.92). CONCLUSION--As the duration of functional mitral regurgitation is effectively fixed, its presence can limit the time available for left ventricular filling in dilated cardiomyopathy when heart rate is high. This may become the mechanism by which maximum heart rate is set, becoming fixed to optimise cardiac output. This manifestation of dilated cardiomyopathy may be an important factor in reduction of heart rate variability in these patients.     

Reduction of false positives in computerized detection of lung nodules in chest radiographs using artificial neural networks,discriminant analysis,and a rule-based scheme

A computer-aided diagnosis (CAD) scheme is being developed to identify image regions considered suspicious for lung nodules in chest radiographs to assist radiologists in making correct diagnoses. Automated classifiers—an artificial neural network, discriminant analysis, and a rule-based scheme—are used to reduce the number of false-positive detections of the CAD scheme. The CAD scheme first detects nodule candidates from chest radiographs based on a difference image technique. Nine image features characterizing nodules are extracted automatically for each of the nodule candidates. The extracted image features are then used as input data to the classifiers for distinguishing actual nodules from the false-positive detections. The performances of the classifiers are evaluated by receiver-operating characteristic analysis. On the basis of the database of 30 normal and 30 abnormal chest images, the neural network achieves an A_Z value (area under the receiver-operating-characteristic curve) of 0.79 in detecting lung nodules, as tested by the round-robin method. The neural network, after being trained with a training database, is able to eliminate more than 83% of the false-positive detections reported by the CAD scheme. Moreover, the combination of the trained neural network and a rule-based scheme eliminates 96% of the false-positive detections of the CAD scheme.     

Pediatric Bipolar Disorder: Evidence-Based Psychopharmacological Treatments

TOPIC: Pediatric bipolar disorder can cause severe disturbances in global functioning. Diagnosing pediatric bipolar disorder is challenging due to the range of symptom expression, developmental differences as compared to adults, presence of comorbid disorders, and developing diagnostic criteria. Treating this disorder can be equally challenging due to frequent symptom relapse and the dearth of research until recently on effective psychopharmacological interventions that guide clinical prescribing practices. PURPOSE: This paper will help child psychiatric nurses have a better understanding of the unique presentation of pediatric bipolar disorder to facilitate selection of appropriate medication treatment options, taking into account symptom presentation, presence of comorbid diagnosis, drug efficacy, adverse effects, and drug-drug interactions based on research findings. SOURCES: Literature specific to assessment and psychopharmacological treatment of pediatric bipolar disorder was reviewed. CONCLUSIONS: Screening of youth with mood spectrum problems for bipolar disorder should occur in every diagnostic assessment and should be ongoing due to range of mood symptoms and the cyclical and episodic nature of this disorder. Youth with bipolar disorder may manifest symptoms and course that differ from adults. Additionally, co-occuring disorders are common in this population, which can complicate medication selection. Psychopharmacological treatment with the use of specific mood stabilizers and/or atypical antipsychotic medications is warranted depending on symptom presentation; however, monotherapy with mood stabilizers has not demonstrated effectiveness in long-term remission of pediatric bipolar symptoms. Recent research indicates that a combined treatment with two mood stabilizers or a mood stabilizer and an antipsychotic holds promising results for pediatric bipolar I, for youth with acute manic symptoms plus psychosis, and for long-term remission of symptoms.     

Precision of Larsen grading of radiographs in assessing progression of rheumatoid arthritis in individual patients.

A study was designed to evaluate observer variation in the assessment of radiographic deterioration of individual patients using the Larsen grading system. Radiographs of hands and feet of 52 patients were assessed by three observers. Each patient had paired films taken one year apart which were assessed together for change in score. To assess within-observer variation each set of films was read twice by all observers. The average progression was 11.6 (SD 9.0). Analysis of the source of variation showed the single observer replication SD to be 3.7 but that for different observers to be 5.5. This may be interpreted as indicating that to achieve 95% confidence of detecting a true change an increase in Larsen score of 8 is required if the same observer assesses or up to 11 if a different observer assesses.     

AN ATTITUDE SURVEY OF LAY-MIDWIVES AND NURSE-MIDWIVES

The increasing legalization of lay-midwifery and its growing practice raise many questions concerning nurse-midwives' involvement with lay-midwives and alternative birth settings. A mailed questionnaire study of a stratified sample of 100 nurse-midwife members of ACNM and 100 lay-midwives was conducted. The questionnaires assessed background in midwifery, characteristics of practice, and attitudes toward CNMs and LMWs by their opposites. The study was not intended as a comparative study of CNMs and LMWs. Instead its focus was primarily on the attitudes that each group expressed regarding members of the opposite group. The profile data revealed that the lay-midwives were young in age and practice and concerned about education and standards of care. The nurse-midwives were older, had practiced longer, and supported alternatives in birth, but were not practicing them. There was no overwhelming positive or negative feeling between the two groups. Both agreed to a relationship on an educational level, but the nurse-midwives were uncertain about formal recognition of lay-midwifery. There were few significant relationships between profile variables and attitudes. The study supplied meaningful data to prompt informed dialogue between nurse-midwives and lay-midwives.     

Model of radiation-impaired healing of a deep excisional wound

Despite many well-recognized benefits, administration of ionizing radiation before surgical resection of malignancies is associated with a high risk of wound-healing complications. Most animal models investigating techniques to improve wound healing use a superficial wound. The goal of this study was to develop a novel model of radiation-impaired healing using a deep excisional wound, which is closer to the clinical situation. In the first part of this study, female Lewis rats were exposed to 0, 12, 15, or 18 Gy single-fraction radiation to the buttocks. Three weeks later, deep wounds were created by excision of the gluteus maximus muscle. Irradiated wounds had a lower rate of healing of the surgically created defect than unirradiated wounds (p<0.001), but there was no significant difference between the different doses of radiation. Impaired healing was still evident at 12 weeks. The second part of this study investigated the ability of porcine small-intestinal submucosa (SIS) to improve healing in this animal model. At 6 weeks, wounds implanted with SIS showed improved healing at all doses of radiation compared with unimplanted irradiated wounds. However, higher doses of radiation were still associated with a lower rate of healing. SIS induced a cellular response that was not evident in defects that did not receive SIS, suggesting that SIS has the potential to stimulate repair. This reproducible model of radiation-impaired wound healing closely resembles the clinical setting. The results indicate that this model can be used to investigate new biomaterials as possible therapeutic agents to enhance wound healing.     

Ethics education in MSN programs: a study of national trends

The aim of this study was to determine the manner in which master's of science in nursing programs, accredited by either the National League for Nursing Accrediting Commission or the Commission on Collegiate Nursing Education, conduct ethics education. A survey method was employed to obtain requisite data. Among the main variables investigated were: the percentage of programs that require a course with formal ethics content; the average number of class hours a program or track dedicates to ethics education; required and actual credentials of instructors who teach ethics; and objectives, topics, teaching methods, and grading methods of required courses with formal ethics content. Results indicated that most programs do not require instructors to have completed formal ethics training. In terms of content, few common trends exist and there are important gaps in clinical ethics topics. Comparisons between school of medicine ethics content reported in the literature and MSN ethics content reported in this study indicate that medical schools are more exacting of their students. The study concludes with a call for the establishment of guidelines or standards relevant to ethics content in MSN curricula in the United States.     

A dual-stage method for lesion segmentation on digital mammograms

Mass lesion segmentation on mammograms is a challenging task since mass lesions are usually embedded and hidden in varying densities of parenchymal tissue structures. In this article, we present a method for automatic delineation of lesion boundaries on digital mammograms. This method utilizes a geometric active contour model that minimizes an energy function based on the homogeneities inside and outside of the evolving contour. Prior to the application of the active contour model, a radial gradient index (RGI)-based segmentation method is applied to yield an initial contour closer to the lesion boundary location in a computationally efficient manner. Based on the initial segmentation, an automatic background estimation method is applied to identify the effective circumstance of the lesion, and a dynamic stopping criterion is implemented to terminate the contour evolution when it reaches the lesion boundary. By using a full-field digital mammography database with 739 images, we quantitatively compare the proposed algorithm with a conventional region-growing method and an RGI-based algorithm by use of the area overlap ratio between computer segmentation and manual segmentation by an expert radiologist. At an overlap threshold of 0.4, 85% of the images are correctly segmented with the proposed method, while only 69% and 73% of the images are correctly delineated by our previous developed region-growing and RGI methods, respectively. This resulting improvement in segmentation is statistically significant.