Biomechanics of a new short-stemmed uncemented hip prosthesis: An in-vitro study in human bone

The migration pattern, cyclic motion, system stiffness and failure load of a new short-stemmed hip prosthesis were compared to a clinically successful shaft prosthesis during the initial loading phase. The influence of implant-sizing on mechanical stability was also investigated for the new stem, in particular with relation to the bone quality. Prostheses were implanted in paired human femora and loaded cyclically up to 3515 cycles. Relative displacements between prosthesis and bone were measured using a 3D-camera and reflective marker system. Migration of the new stem was predominantly into varus and was higher than for the shaft prosthesis. The test set-up was proposed to simulate a worst-case loading scenario since muscle forces, which tend to reduce bone deformation, were not simulated. It could therefore be expected that clinical migration of the implants would be less pronounced than that observed in this study. Cyclic motion for the new stem was similar to that for the clinically successful shaft prosthesis, suggesting that bone ingrowth could be expected for the new stem. No significant difference in fracture load was observed between the implants. The system stiffness with the new stem was lower than for the shaft prosthesis, indicating more physiological load transfer. Smaller implant sizing with 'cancellous' fixation seems favourable, as it led to similar migration and smaller cyclic motion values than with 'cortical' fixation. A trend for higher cyclic motion and migration was observed in femora with poor bone quality. Hence, sufficiently good bone stock is necessary, when implanting the new short-stemmed prosthesis.

Factors related to cancer screening in Hispanics: a comparison of the perceptions of Hispanic community members, health care providers, and representatives of organizations that serve Hispanics

Hispanics have lower rates of screening for cervical, breast, and colon cancer than non-Hispanics. Activities to increase cancer screening in this population may not be informed by Hispanics, which may have implications for success rates of interventions. In this study, the perceptions about cancer screening behaviors in Hispanics are compared among three groups: a random sample of respondents (75% Hispanic) to a population-based survey, health care providers (primarily non-Hispanic), and representatives of organizations that serve Hispanics (36% Hispanic). While there was agreement that socioeconomic factors were important for cancer screening, differing views were expressed regarding the importance of cultural factors for cancer screening among Hispanics. Interventions developed by those who serve the Hispanic population may be based on inaccurate perceptions about the beliefs and practices of the population served. For effective interventions, it will be necessary to understand the factors important to Hispanics for cancer screening.

Identifying constituents to participate in a project to control pesticide exposure in children of farmworkers

Farmers in Washington State use pesticides to control harmful pests that might interfere with the quality of their products. Farmworkers, who are primarily responsible for thinning, harvesting, and other agricultural work, are often exposed to these pesticides and take home pesticide residues on their clothing, shoes, and skin, potentially exposing children in the household to pesticides. We designed a project to reduce children's exposure by using a community organization model. To better understand the community views regarding pesticide exposure, we conducted a qualitative community analysis. Two methods of data gathering were used to collect information. Individual interviews were conducted with some respondents, and small group discussions were held with others. Analysis indicated wide disparity among involved groups in their views on pesticides; however, a number of themes common to the majority of the constituents were identified and discussed with a community planning group. Because of the contention around pesticides, the group recommended every constituent participate in decision making. The group noted it was important to emphasize that the research project could provide scientific information on pesticide exposure to everyone in the Lower Yakima Valley. Our study demonstrates both the widely varying views of different constituents around the issue of pesticide exposure and common themes that can form the basis for collaboration and consensus on approaching the issue.

Comparative brain pathology of HIV-seronegative and HIV-infected drug addicts

Early stages of infection with human immunodeficiency virus (HIV) were studied in HIV-seropositive drug addicts. Since heroin users are immunocompromized even in the absence of HIV infection, the aim of the present study was to compare the morphological alterations present in HIV-seronegative and HIV-seropositive drug addicts. A total of 60 cases (32 HIV-seronegative subjects, 21 HIV-seropositive patients without signs of acquired immunodeficiency syndrome (AIDS), and 7 HIV-seropositive patients with signs of AIDS) were investigated macroscopically, histologically, and immunohistochemically HIV-seronegative patients presented more frequently with acute drug intoxication, died at a significantly younger age than HIV-seropositive patients, and were found to suffer more frequently from alcohol-related changes. These results indicated that HIV-seronegative and HIV-seropositive patients differed possibly in their drug consumption and also in their general conditions of life. In accordance with previous reports activated microglia and a diffuse astrogliosis in the white matter were detected at a significantly higher frequency and found to be more severe in HIV-seropositive subjects than in HIV-seronegative addicts. A lymphocytic meningitis was present in 6 of 21 HIV-seropositive patients but in none of the HIV-seronegative patients. Perivascular infiltrates consisting of lymphocytes and macrophages were detected at similar frequencies in HIV-seronegative and HIV-seropositive patients but were significantly more severe in patients suffering from lymphocytic meningitis or purulent encephalitis. Opportunistic infections were only demonstrated in 2 AIDS cases. In 10 of the HIV-seronegative patients and in 3 of the HIV-seropositive patients CD68-and Ham56-positive multinucleated cells were detected scattered in the subarachnoidal space exclusively over the frontal cortex.

Morphometrical analysis of retinal hemorrhages in the shaken baby syndrome

A morphometrical analysis of retinal hemorrhages was performed in cases of physical child abuse including the shaken baby syndrome and in controls (severe head injury, intravital brain death, non-traumatic intracranial hemorrhage, SIDS including cardiopulmonary resuscitation). The extent of the retinal hemorrhages was significantly different between both groups. In all cases of physical child abuse, massive retinal hemorrhages in at least one eye could be found ranging between a maximum value of 19.2 and 73.2% of the entire retinal area. In contrast, only two cases of the control group (severe head injury with skull fractures and intracranial bleeding following traffic accident or fall) showed slight hemorrhages of 3.33 or 1.18% of the retinal area but only in one eye. Therefore, the results provide evidence that massive intraretinal hemorrhages indicate violent shaking -- in particular in association with other signs of physical child abuse.

[Early test of thallium dipyridamole after myocardial infarction: prognostic value and correlation with coronarography]

Fifty three patients were studied with dipyridamole thallium myocardial scintigraphy, 4 to 6 days after a first episode of myocardial infarction. Localization of infarction was anterior in 25 and inferior in 28. Infarction was confirmed by myocardial scintigraphy in 87% of cases. A non q wave myocardial infarction was present in 5 of the 7 patients with negative scintigraphy. Residual myocardial ischemia was suggested by myocardial scintigraphy in 68% of patients. Correlated to coronary arteriography, sensitivity for myocardial ischemia was 80%, specificity 82%. After a mean follow up of 11.2 months, 22 of 36 patients with positive myocardial scintigraphy had new coronary events, 15 of them requiring myocardial revascularization. In contrast, only 2 of 17 patients with negative scintigraphy had new events (p < 0.05). Thus dipyridamole thallium myocardial scintigraphy early after myocardial infarction is a valuable prognostic test.