Public participation in radiological surveillance

In 1989, Pacific Northwest National Laboratory developed a program, for the U.S. Department of Energy, to involve local citizens in environmental surveillance at the Hanford Site. The Community-Operated Environmental Surveillance Program was patterned after similar community-involvement efforts at the Nevada Test Site and the Three Mile Island nuclear facility. Its purpose is to increase the flow of information to the public, thereby enhancing the public's awareness and understanding of surveillance activities. The program consists of two components: radiological air monitoring at nine offsite locations and agricultural product sampling at selected locations near the site. At each air-monitoring station, two local school teachers collect air particulate samples and operate equipment to monitor ambient radiation levels. Atmospheric tritium samples (as water vapor) are also collected at some locations. Four of the air-monitoring stations include large, colorful informational displays for public viewing. These displays provide details on station equipment, sample types, and sampling purposes. Instruments in the displays also monitor, record, and show real-time ambient radiation readings (measured with a pressurized ionization chamber) and meteorological conditions. Agricultural products, grown primarily by middle-school-aged students, are obtained from areas downwind of the site. Following analysis of these samples, environmental surveillance staff visit the schools to discuss the results with the students and their teachers. The data collected by these air and agricultural sampling efforts are summarized with other routinely collected sitewide surveillance data and reported annually in the Hanford Site environmental report.     

Comparison between morphologic changes seen on high-resolution CT and regional pulmonary perfusion seen on SPECT in patients with cystic fibrosis

OBJECTIVE: To evaluate the relationship between morphologic findings seen on high-resolution computed tomography (HRCT) of the lung and regional lung perfusion depicted on single photon-emission computed tomography (SPECT) pulmonary perfusion imaging in patients with cystic fibrosis. MATERIALS AND METHODS: Ten HRCT and 10 technetium-99 m macroaggregated albumin SPECT pulmonary perfusion imaging studies were performed on eight young adult patients who were considered to be clinically well and have mild to moderate cystic fibrosis. HRCT scans of the chest were evaluated using a CT scoring system which included grading of bronchiectasis, peribronchial thickening, hyperlucency, bullae, collapse/consolidation, and mucus plugging. Each lung was divided into six anatomic zones which were independently scored. A lung perfusion score (between 0 and 100), reflecting the percentage of compromised lung, was estimated for each zone. Axial lung perfusion SPECT images were matched anatomically to HRCT images. Lung function was considered compromised when the counts per pixel were less than 25 % of the count level seen in an area of the same patient's lung which was judged to be normal. RESULTS: There was a statistically significant relationship (P = 0.0001) between HRCT total scores and SPECT lung perfusion scores as well as between hyperlucency scores by HRCT and the SPECT lung perfusion scores. However, the HRCT score was a poor predictor of the lung perfusion score in zones with intermediate HRCT scores, which constituted 106 of 120 zones. CONCLUSION: Morphologic changes depicted by HRCT correlate with decreased lung pefusion on SPECT. However, HRCT changes accurately predict regional lung function only in the most normal and severely diseased lung zones.     

Clinical trial of retrograde warm blood reperfusion versus standard cold topical irrigation of transplanted hearts

BACKGROUND: A prospective, randomized clinical study involving 34 patients undergoing heart transplantation compared myocardial preservation of donor hearts maintained with continuous reperfusion with retrograde warm blood cardioplegia during surgical implantation versus the standard cold topical irrigation. METHODS: Hearts in both groups were arrested with a standard crystalloid solution and maintained in a cold saline solution during transportation. In the retrograde group, cardioplegia was administered through a catheter in the coronary sinus during surgical implantation. An average of 471 +/- 30 mL of hyperkalemic crystalloid solution diluted 1:4 in warm blood from the oxygenator was infused. In the standard group, the heart was kept cold by topical irrigation of cold saline solution and was reperfused only when the ascending aorta was unclamped. RESULTS: Preoperative characteristics of donors and recipients were similar in the two cohorts. Ischemic time average 139 +/- 12 minutes in the retrograde group compared with 130 +/- 11 minutes in the standard group (p = 0.57). Cardiopulmonary bypass time averaged 89 +/- 4 minutes in the retrograde group and 110 +/- 12 minutes in the standard group (p = 0.12). Defibrillation at reperfusion was performed in 4 patients (4/17, 24%) in the retrograde group and 12 patients (12/18, 67%) in the standard group (p = 0.01). There were no deaths in the retrograde group (0/17), whereas in the standard group, 3 patients (3/17) died of early graft failure (p = 0.11). Four early graft failures occurred in the standard group (p = 0.06). Two patients (2/17, 12%) were weaned from bypass with ventricular assist devices in the standard group. The number of subendocardial necrotic cells in the first two weekly endomyocardial biopsy specimens averaged 2.7 +/- 0.8 cells/mm2 in the retrograde group and 5.9 +/- 2.4 cells/mm2 in the standard group (p = 0.12). CONCLUSIONS: Retrograde warm blood reperfusion appears to improve the initial recovery of transplanted hearts. The technique is easy to use and may be a useful approach to graft protection during surgical implantation.     

Assessment of pseudarthrosis in pedicle screw fusion: a prospective study comparing plain radiographs, flexion/extension radiographs, CT scanning, and bone scintigraphy with operative findings

Tribal warfare is a way of life in the highlands of Papua New Guinea. In earlier times direct confrontation with bushknives and axes, and shooting with bows and arrows were common. In recent years there have not been as many instances of direct confrontation with bushknives and axes, but the use of bows and arrows is on the rise. Since 1993, guns have been increasingly used, with devastating results. In 1993, 18 deaths were reported from tribal warfare in one area of the Southern Highlands Province, especially from gunshots, while in 1994, 24 deaths were reported from another area. A five-year review of tribal fight admissions to Mendi Hospital, from 1990 to 1994, showed an increase in the number and proportion of gunshot wounds; there were none in 1990-1992 but they constituted 18% of tribal fight injuries in 1993 and 33% in 1994.     

Offset dual-disk dielectric resonator antenna of very highpermittivity

An aperture-coupled offset dual-disk dielectric resonator antenna of very high permittivity is investigated experimentally. It is found that the new configuration offers an impedance bandwidth 4.6 times wider than that of the single element. The voltage standing wave ratio, radiation patterns, and antenna gain of the configuration are studied     

Vascular rejection post heart transplantation is associated with positive flow cytometric cross-matching

28 isolates of canine parvovirus type-2 (CPV-2) were obtained from dogs with hemorrhagic gastroenteritis in Italy. The antigenic structure of CPV-2 isolates was characterized, using four discriminating monoclonal antibodies. In addition, four vaccinal strains were examined. Similar to reports from Australia and the United Kingdom, a much higher prevalence of CPV-2a (25/28 isolates) was observed than the other variant type, CPV-2b (3/28 isolates). DNA fragments (2.2 kbp) of representative strains of CPV-2, CPV-2a and CPV-2b were amplified by the polymerase chain reaction (PCR) and the products were digested by the restriction enzymes (RE) RsaI, HpaII, HindIII and PvuII. The RvaI enzyme allows the differentiation of CPV-2 from CPV-2a and CPV-2b.     

MNav: A Markov Model-Based Web Site Navigability Measure

Web site success is significantly associated with navigability, an important attribute of usability that denotes the ease with which users find desired information as they move through a Web site. Navigable Web sites allow users to form a mental model of the type and location of information in the Web site and an expectation of where and to what a particular hyperlink will lead. Existing navigability measures are based mainly on the static hyperlink structure of a Web site. Such measures, however, have two main drawbacks: 1) the effect on navigability of a hyperlink structure cannot be well characterized and 2) the effect on navigability of the navigation aids (such as the "Back" button provided by a browser) is ignored. In this paper, we abstract a dynamic Web surfing behavior as a Markov model which synthesizes typical surfing actions. Based on this model, we propose a novel navigability measure MNav. The experimental results show that MNav can be efficiently computed and it provides an effective and useful measurement of Web site navigability.     

Projection status of calbindin- and parvalbumin-immunoreactive neurons in the superficial layers of the rat's superior colliculus

Immunocytochemistry and retrograde labeling were used to define the thalamic projections of calbindin- and parvalbumin-containing cells in superficial layers of the rat's superior colliculus (SC). Quantitative analysis revealed that 90.8 +/- 2.2% (mean +/- standard deviation) of the calbindin-immunoreactive neurons in the stratum griseum superficiale (SGS) projected to the dorsal lateral geniculate nucleus (LGNd) and that 91.3 +/- 4.3% of calbindin-immunoreactive neurons in the stratum opticum (SO) projected to the lateral posterior nucleus (LP). In contrast, only 17.3 +/- 2.5% of parvalbumin-immunoreactive neurons in the SGS were found to project to the LGNd and 16.5 +/- 3.1% of the parvalbumin-immunoreactive SO cells were retrogradely labeled after LP injections. Few of the parvalbumin-immunoreactive neurons in either the SGS (7.2 +/- 2.5%) or the SO (9.2 +/- 2.5%) were GABA positive. The retrograde-labeling results suggest that parvalbumin-immunoreactive neurons in the rat's SO and SGS may either be primarily interneurons or have descending projections, while calbindin-containing cells are primarily thalamic projection neurons. These results are consistent with data from other rodents, but almost exactly the opposite of data that have been reported for the cat for these same populations of SC projection neurons. Such interspecies differences raise questions regarding the functional importance of expressing one calcium-binding protein versus another in a specific neuronal population.     

Fatal heatstroke in a young woman with previously undiagnosed Hashimoto's thyroiditis

Heatstroke represents the most severe form of the heat-related illnesses. Potentially fatal, heatstroke most often affects the elderly, obese, or chronically ill. Thyroid disease, which may interfere with the normal regulation of body temperature, has not previously been reported in cases of heatstroke. A fatal case is reported in a young woman discovered unconscious in a sauna who was found to have preexisting Hashimoto's thyroiditis on subsequent autopsy. The diagnosis of hypothyroidism in heatstroke rests on clinical information and morphologic observations. This case underscores the importance of evaluating the thyroid in unusual cases of heatstroke.