Evaluation of a "walk-through" ladder top design during ladder-roof transitioning tasks.

This study evaluated the effect of an extension ladder "walk-through" top design on kinetic and kinematic behaviors and the outward destabilizing forces induced on the ladder during transitioning at elevation. Thirty-two male participants performed stepping tasks between a ladder top and a roof at simulated elevation in a surround-screen virtual-reality system. The experimental conditions included a "walk-through" and a standard ladder top section supported on flat and sloped roof surfaces. Three force platforms were placed under the ladder section and in the roof to measure propulsion forces during transitions. A motion measurement system was used to record trunk kinematics. The frictional demand at the virtual ladder base was also calculated. The results indicate that under optimal ladder setup (angle 75.5 °), the frictional demand at the ladder base remains relatively small for all experimental conditions. Also, the "walk through" ladder top eased the ladder-to-roof transitions but not the roof-to-ladder transitions.

Flat detector angio-CT following intra-arterial therapy of acute ischemic stroke: identification of hemorrhage and distinction from contrast accumulation due to blood-brain barrier disruption.

BACKGROUND AND PURPOSE: Flat panel detector CT in the angiography suite may be valuable for the detection of intracranial hematomas; however, abnormal contrast enhancement frequently mimics hemorrhage. We aimed to assess the accuracy of flat panel detector CT in detecting/excluding intracranial bleeding after endovascular stroke therapy and whether it was able to reliably differentiate hemorrhage from early blood-brain barrier disruption. MATERIALS AND METHODS: Seventy-three patients were included for retrospective evaluation following endovascular stroke therapy: 32 after stent-assisted thrombectomy, 14 after intra-arterial thrombolysis, and 27 after a combination of both. Flat panel CT images were assessed for image quality and the presence and type of intracranial hemorrhage and BBB disruption by 2 readers separately and in consensus. Follow-up by multisection head CT, serving as the reference standard, was evaluated by a single reader. RESULTS: Conventional head CT revealed intracranial hematomas in 12 patients (8 subarachnoid hemorrhages, 7 cases of intracerebral bleeding, 3 SAHs plus intracerebral bleeding). Image quality of flat panel detector CT was considered sufficient in all cases supratentorially and in 92% in the posterior fossa. Regarding detection or exclusion of intracranial hemorrhage, flat panel detector CT reached a sensitivity, specificity, positive and negative predictive values, and accuracy of 58%, 85%, 44%, 91%, and 81%, respectively. Maximum attenuation measurements were not valuable for the differentiation of hemorrhage and BBB disruption. CONCLUSIONS: Flat panel CT after endovascular stroke treatment was able to exclude the rare event of an intracranial hemorrhage with a high negative predictive value. Future studies should evaluate the predictive value of BBB disruptions in flat panel detector CT for the development of relevant hematomas.

Research to improve extension ladder angular positioning.

A leading cause for extension ladder fall incidents is a slide-out event usually related to suboptimal ladder inclination. An improved ladder positioning method or procedure could reduce the risk of ladder stability failure and the related fall injury. The objective of the study was to comparatively evaluate the effectiveness of a multimodal angle indicator with other existing methods for extension ladder angular positioning. Twenty experienced and 20 inexperienced ladder users participated in the study. Four ladder positioning methods were tested in a controlled laboratory environment with 4.88 m (16 ft) and 7.32 m (24 ft) ladders in extended and retracted positions. The positioning methods included a no-instruction method, the current standard anthropometric method, and two instrumental methods - a bubble level indicator, and a multimodal indicator providing direct feedback with visual and sound signals. Performance measures included positioning angle and time. The results indicated that the anthropometric method was effective in improving the extension ladder positioning angle (p < 0.001); however, it was associated with considerable variability and required 50% more time than no-instruction. The bubble level indicator was an accurate positioning method (with very low variability), but required more than double the time of the no-instruction method (p < 0.001). The multimodal indicator improved the ladder angle setting as compared to the no-instruction and anthropometry methods (p < 0.001) and required the least time for ladder positioning among the tested methods (p < 0.001). An indicator with direct multimodal feedback is a viable approach for quick and accurate ladder positioning. The main advantage of the new multimodal method is that it provides continuous feedback on the angle of the device and hence does not require repositioning of the ladder. Furthermore, this indicator can be a valuable tool for training ladder users to correctly apply the current ANSI A14 standard anthropometric method in ladder angular positioning. The multimodal indicator concept has been further developed to become a hand-held tool in the form of a smart phone application.

[Clinical application of flat-panel CT in the angio suite]. / Klinische Anwendung der Flachdetektor-CT im Angio-OP.

The introduction of flat-panel detectors in modern angiographic C-arm systems makes it possible to acquire CT-like images in the angiographic suite (flat-panel CT; FD-CT). In this review, after a short technical introduction of FD-CT including the discussion of the advantages and disadvantages of this new imaging modality, the most commonly and best evaluated indications for FD-CT will be described. FD-CT has become an important adjunctive imaging modality in neurointerventional procedures and embolizations, especially during liver embolization. Another attractive indication for FD-CT is musculoskeletal interventions. FD-CT may provide important additional information in complicated peripheral vascular interventions and stent-graft procedures. FD-CT has a broad spectrum of possible applications, which finally depends on the experience and innovative thinking of the operator. However, it has to be kept in mind that FD-CT causes additional radiation exposure. Roughly, it can be assumed that currently one FD-CT sequence causes at least the same radiation exposure as one spiral CT sequence of the corresponding body region.

Postural stability effects of random vibration at the feet of construction workers in simulated elevation.

The risk of falls from height on a construction site increases under conditions which degrade workers' postural control. At elevation, workers depend heavily on sensory information from their feet to maintain balance. The study tested two hypotheses: "sensory enhancement"--sub-sensory (undetectable) random mechanical vibrations at the plantar surface of the feet can improve worker's balance at elevation; and "sensory suppression"--supra-sensory (detectable) random mechanical vibrations can have a degrading effect on balance in the same experimental settings. Six young (age 20-35) and six aging (age 45-60) construction workers were tested while standing in standard and semi-tandem postures on instrumented gel insoles. The insoles applied sub- or supra-sensory levels of random mechanical vibrations to the feet. The tests were conducted in a surround-screen virtual reality system, which simulated a narrow plank at elevation on a construction site. Upper body kinematics was assessed with a motion-measurement system. Postural stability effects were evaluated by conventional and statistical mechanics sway measures, as well as trunk angular displacement parameters. Analysis of variance did not confirm the "sensory enhancement" hypothesis, but provided evidence for the "sensory suppression" hypothesis. The supra-sensory vibration had a destabilizing effect, which was considerably stronger in the semi-tandem posture and affected most of the sway variables. Sensory suppression associated with elevated vibration levels on a construction site may increase the danger of losing balance. Construction workers at elevation, e.g., on a beam or narrow plank might be at increased risk of fall if they can detect vibrations under their feet. To reduce the possibility of losing balance, mechanical vibration to supporting structures used as walking/working surfaces should be minimized when performing construction tasks at elevation.

MR angiographic follow-up of intracranial aneurysms treated with detachable coils: evaluation of a blood-pool contrast medium.

BACKGROUND AND PURPOSE: Blood-pool agents are promising in the imaging of small vessels with slow or complex flow. Our aim was to compare blood-pool contrast-enhanced MR angiography (BPCE-MRA) using gadofosveset trisodium (Vasovist) with 3D time-of-flight MRA (TOF-MRA) in the follow-up of intracranial aneurysms after endovascular therapy. MATERIALS AND METHODS: We included 32 patients with a total of 37 coiled aneurysms. MRAs in the early steady-state phase were performed on a 1.5T scanner within 8 days of digital subtraction angiography (DSA). Two radiologists independently analyzed TOF-MRA and BPCE-MRA images. Consensus was reached by review involving a third neuroradiologist. DSA images were interpreted separately by an interventional radiologist. Findings were assigned to 1 of 3 categories: 1) complete occlusion, 2) residual neck, and 3) residual aneurysm. RESULTS: Follow-up DSA demonstrated 13 complete obliterations (class 1), 13 residual necks (class 2), and 11 residual aneurysms (class 3). Weighted kappa statistics showed substantial concordance of TOF-MRA and DSA (0.664) as well as BPCE-MRA and DSA (0.724) ratings. Comparison between TOF-MRA and BPCE-MRA found excellent agreement (0.818) with only 6 (16.2%) discrepancies. For detecting residual flow, the difference in accuracy of both MRA techniques (83.8% versus 91.9%) was not significant (McNemar, P = 1.000). BPCE-MRA showed a tendency towards higher sensitivity and specificity (91.7% and 92.3%, respectively) compared with TOF-MRA (87.5% and 76.9%). CONCLUSIONS: In classifying the completeness of endovascular cerebral aneurysm therapy, we found that BPCE-MRA and 3D TOF-MRA showed very good agreement. The use of Vasovist did not lead to a significantly increased accuracy of MRA follow-up.

[Flat-panel CT as a new perinterventional imaging modality in aortic stentgraft procedures--work in progress]. / Flachdetektor-CT als ergänzende Untersuchung bei der endoluminalen Behandlung von thorakalen und abdominellen Aortenaneurysmen--Erste klinische Erfahrungen.

PURPOSE: To evaluate the value of flat-panel CT (FP-CT) as a new perinterventional imaging modality in aortic stentgraft procedures. MATERIALS AND METHODS: FP-CT was performed in 21 patients (19 males, mean age 77, range 54 to 90) from June 2005 to February 2007 immediately after endovascular treatment of thoracic and abdominal aortic aneurysms on the angiographic table. Nine thoracic aortic aneurysms were treated with Zenith-endoprosthesis. Nine of twelve abdominal aortic aneurysms were treated with Zenith-endoprosthesis and three with an Excluder-endoprosthesis. Images were acquired with a rotating C-arm and the following parameters: during an acquisition time of 20 seconds and at a rotation of 217 degrees, 538 projections were acquired. Contrast agent was administered in 14 patients. Images were displayed in MIP, MPR and VRT mode. RESULTS: In all patients the stentgraft was shown exactly and the alignment of the prosthesis along the landing zones was well displayed. The aneurismal sack was well shown in all patients. 1 x an endoleak II was detected, 1 x an angiographically verified endoleak I was not detected. In one patient distal extension was considered due to suspected short stentgraft at the distal neck. Flat-panel CT showed sufficient neck coverage and no extension was inserted. Due to artifacts of the prosthesis, the platinum markers and the guide wire as well as due to pulsation of the aorta, the resolution of detail decreased and reduced the visualization of the alignment. CONCLUSION: FP-CT is a promising tool and may provide additional information, but further studies are necessary to define the value of flat-panel CT in thoracic and abdominal aortic stentgraft procedures.

Clinical experience with a commercially available negative oral contrast medium in PET/CT.

PURPOSE: To evaluate a commercially available negative oral contrast material for PET/CT. MATERIAL AND METHODS: In a prospective series of 49 patients, Mukofalk, which is a vegetarian-based substance, was used as a negative oral contrast medium in whole body PET/CT studies. Mukofalk was administered during a time period of 1.5 hours before the examination. Quality of small bowl distension and eventual pathological tracer uptake in the intestine were evaluated. RESULTS: Distension of the small bowel was excellent or good in 41 (85 %) and poor in 8 (15 %) patients. Mild tracer uptake in the small bowel was observed in 5 patients (10.2 %) and moderate uptake in another 2 patients (4 %). In none of these patients did the F-18 FDG uptake interfere with image interpretation. CONCLUSION: Mukofalk can be used as a negative oral contrast medium in PET/CT studies.

Anthropometric criteria for the design of tractor cabs and protection frames.

Improved human-tractor interface designs, such as well-accommodated operator enclosures (i.e. cabs and protection frames) can enhance operator productivity, comfort and safety. This study investigated farm-worker anthropometry and determined the critical anthropometric measures and 3-D feature envelopes of body landmarks for the design of tractor operator enclosures. One hundred agriculture workers participated in the study. Their body size and shape information was registered, using a 3-D full-body laser scanner. Knee height (sitting) and another eight parameters were found to affect the cab-enclosure accommodation rating and multiple anthropometric dimensions interactively affected the steering wheel and gear-handle impediment. A principal component analysis has identified 15 representative human body models for digitally assessing tractor-cab accommodation. A set of centroid coordinates of 34 body landmarks and the 95% confidence semi-axis-length for each landmark location were developed to guide tractor designers in their placement of tractor control components in order to best accommodate the user population. Finally, the vertical clearance (90 cm) for agriculture tractor enclosure in the current SAE International J2194 standard appeared to be too short as compared to the 99th percentile sitting height of male farm workers in this study (100.6 cm) and in the 1994 National Health and Nutrition Examination Survey III database (99.9 cm) and of the male civilian population in the 2002 Civilian American and European Surface Anthropometric Resource database (100.4 cm).

Lung cancer in women: analysis of the national Surveillance, Epidemiology, and End Results database.

OBJECTIVES: In order to further characterize the effect of gender on the clinicopathologic features and survival of patients with lung cancer, and to determine gender-associated differences in temporal trends, we analyzed data that had been entered into a population-based cancer database. PATIENTS AND METHODS: Data on demographics, stage at diagnosis, histology, initial therapy, and survival were obtained on all patients with primary bronchogenic carcinoma registered in the national Surveillance, Epidemiology, and End Results database from 1975 to 1999. RESULTS: Of the 228,572 eligible patients, 35.8% were female. The median age at diagnosis was 66 years for both men and women. However, women accounted for 40.9% of patients who were < 50 years of age and for 35.4% of older patients. The incidence of lung cancer in men peaked at 72.5 per 100,000 person-years in 1984 and then declined to 47 per 100,000 person-years by 1999. In women, the incidence continued to rise to a peak of 33.1 per 100,000 person-years in 1991 before reaching a plateau at 30.2 to 32.3 per 100,000 person-years from 1992 to 1999. These changes have resulted in a marked narrowing of the male/female incidence ratio from 3.56 in 1975 to 1.56 in 1999. As initial treatment, women with local disease underwent surgery more frequently than did men. Stage-specific survival rates were better for women at all stages of disease (p < 0.0001). In a multivariate analysis, male gender was an independent negative prognostic factor (p < 0.0001). CONCLUSION: The incidence rate of lung cancer in women in the United States has reached a plateau. However, women are relatively overrepresented among younger patients, raising the question of gender-specific differences in the susceptibility to lung carcinogens. At each stage of the disease, the relative survival of women is better than that of men, with the largest difference noted in patients with local disease.

Prostate-specific antigen in a community screening program.

BACKGROUND: This study was designed to determine who participates in community-based prostate-specific antigen (PSA) screening programs and what serum PSA levels can be expected. METHODS: A descriptive analysis of men who participated in an annual community health screening program was used to compare men who chose PSA screening with those who did not. The relationship of demographic variables to PSA level was evaluated by multivariate regression analysis. Data were available on 5548 men, 6% of whom were black. RESULTS: The population of PSA screening participants included proportionately more middle-aged white men with higher median income, as compared with men who did not participate. Those who did not participate in the screening were more likely to be either very old or very young. PSA levels increased with age, and the percentage of men with elevated PSA levels increased with age. One tenth (9.6%) of all participants had PSAs between 4 ng/mL and 10 ng/mL, and 1.9% had levels greater than 10 ng/mL. Within 1 year of the screening, 1.7% of the screened participants had a diagnosis of prostate cancer. The mean PSA in this group was 15.9 ng/mL. CONCLUSIONS: These data confirm the need for age-specific PSA reference ranges. It is likely that the same reference range can be used for all racial ethnic populations.

Effect of age and race on the survival of men with prostate cancer in the Metropolitan Detroit tricounty area, 1973 to 1987.

OBJECTIVES: Reports have demonstrated that African Americans diagnosed with prostate cancer have a poor survival compared with whites. We examined the impact of age, race, and stage of disease on survival for men diagnosed with prostate cancer. METHODS: A retrospective analysis was made of men diagnosed with prostate cancer utilizing the Surveillance, Epidemiology, and End Results Program (SEER) database. A total of 12,907 men (9339 white, 3568 black) diagnosed from January 1, 1973 through December 31, 1987 were included in the study. For each stage of disease, survival experience was examined using Kaplan-Meier and life table methods, followed by analysis using Cox's proportional hazard model. RESULTS: African-American men have a poorer survival than whites for all stages of prostate cancer when the cancer is diagnosed at younger ages. These differences in survival were not demonstrated for men diagnosed with prostate cancer after age 70. CONCLUSIONS: Age and race should be taken into account when assessing the survival of patients with prostate cancer.

Increasing incidence of cancer of the prostate. The experience of black and white men in the Detroit metropolitan area.

BACKGROUND: Prostate cancer mortality and incidence rates have been gradually increasing for decades in the United States, with an accelerated increase in incidence noted in the past several years. This study explores in detail the occurrence of prostate cancer in southeast Michigan from 1973 through 1991. METHODS: Data from the National Cancer Institute Surveillance, Epidemiology, and End Results program are analyzed with emphasis on time trends by race, age, stage, and treatment. RESULTS: Population-based rates for prostate cancer increased by 70% between 1988 and 1991. Increases are most pronounced for early stage disease and among whites compared with blacks. Corresponding increases in treatment with radical prostatectomy are also observed. CONCLUSION: Increased incidence of prostate cancer is likely a result of widespread use of prostate-specific antigen.

Trends in cervical cancer incidence among young black and white women in metropolitan Detroit.

BACKGROUND: Although the overall incidence of invasive cervical cancer in the United States has declined over the past several decades, recent studies suggest that rates for both invasive and in situ cervical cancer are rising among younger women. METHODS: Trends in cervical cancer incidence among females between the ages of 15 and 39 years were evaluated using data from the Metropolitan Detroit Cancer Surveillance System, a population-based registry and founding participant in the SEER Program of the National Cancer Institute. Age-adjusted and age-specific rates for all black and white women in this age group were evaluated as well as rates for married and single women for the period 1973-1991. RESULTS: Incidence trends vary by race and marital status. A nonlinear increasing trend was evident (P < 0.01), for in situ cervical cancer among white women, with rates for single white women exhibiting the largest increase. Rates among black women for in situ cervical cancer exhibited a nonlinear decreasing trend (P < 0.01), with rates for married black women declining by 75%. Among single white women, invasive cervical cancer exhibited an increasing linear trend (P < 0.01), although the number of cases was small. CONCLUSIONS: Differences in trends among black and white women may reflect a combination of greater exposure to risk factors associated with cervical carcinoma as well as differential access to diagnostic and treatment services. Appropriate groups should be targeted for educational, screening, and follow-up services.

[Normal and disordered visual development with preferential looking]. / Untersuchungen zur normalen und gestörten visuellen Entwicklung mit Preferential Looking (PL).

Normal and disturbed development of grating acuity in preverbal infants has been studied using the Teller acuity card procedure. The results of 195 normal and 34 premature children are in good accordance with those reported in the literature. In more than 86% no interocular differences of grating acuity could be detected in these groups. On the other hand the incidence of interocular acuity differences reached 30% in 37 cases showing monolateral convergent squint. This is much higher than has been reported in current literature and may indicate that grating and Snellen acuity correlate better than expected in infants' squint amblyopia. As to the problem of monitoring early amblyopia therapy by PL, four longitudinal cases are presented.