Influence of bound dodecanoic acid on the reconstitution of albumin nanoparticles from a lyophilized state.

The development of reference standards for nanoparticle sizing allows for cross laboratory studies and effective transfer of particle sizing methodology. To facilitate this, these reference standards must be stable upon long-term storage. Here, we examine factors that influence the properties of cross-linked albumin nanoparticles, fabricated with an ethanol desolvation method, when reconstituted from a lyophilized state. We demonstrate, with nanoparticle tracking analysis, no significant changes in mean particle diameter upon reconstitution of albumin nanoparticles fabricated with bovine serum albumin loaded with dodecanoic acid, when compared to nanoparticles fabricated with a fatty acid-free BSA. We attribute this stability to the modulation of nanoparticle charge-charge interactions at dodecanoic acid specific binding locations. Furthermore, we demonstrate this in a lyophilized state over six months when stored at - 80 °C. We also show that the reconstitution process is readily transferable between technicians and laboratories and further confirm our finding with dynamic light scattering analysis.

Interaction of cognitive aging and memory deficits related to epilepsy surgery.

Temporal lobe epilepsy surgery can cause significant memory impairment. This study was intended to examine whether surgery also could affect prognosis of memory in older age. Age regression of verbal memory was examined in 187 patients (before and 1 year after left temporal lobe surgery) and 264 healthy controls. Eighty patients underwent selective amygdalohippocampectomy, and 107 patients underwent anterior two-thirds temporal lobectomy. Amygdalohippocampectomy patients had mesiotemporal epilepsy; anterior two-thirds temporal lobectomy patients had more extramesial or diffuse seizure onset zones. Memory was assessed by word list learning for its more mesial (consolidation/retrieval) and more neocortical (learning) aspects. Patients showed significant preoperative memory impairment. Independent of seizure outcome and surgical approach, surgery had significant negative effects on learning and consolidation/retrieval. In the amygdalohippocampectomy group, preoperative and postoperative age regressions of learning and consolidation/retrieval were not different from those of controls. In the anterior two-thirds temporal lobectomy group, age regression of verbal learning became steeper after surgery, and consolidation/retrieval was negatively correlated with older age and later onset of epilepsy even before surgery. The data confirm that age regression of verbal memory in left temporal lobe epilepsy is similar to that in healthy controls. Both left anterior two-thirds temporal lobectomy and amygdalohippocampectomy worsen verbal learning and memory and bring patients closer to cognitive disability. Particularly in anterior two-thirds temporal lobectomy patients, surgery and reduced capacities for compensation cause acceleration of lifetime memory decline. The results support earlier and tailored epilepsy surgery and suggest that memory prognosis in older age should be considered if more extensive temporal resections would be inevitable.

Consequences of a biological invasion reveal the importance of mutualism for plant communities.

Seed-dispersal mutualisms have a fundamental role in regenerating natural communities. Interest in the importance of seed dispersal to plant communities has been heightened by worldwide declines in animal dispersers. One view, the 'keystone mutualist hypothesis', predicts that these human-caused losses will trigger a cascade of linked extinctions throughout the community. Implicitly, this view holds that mutualisms, such as seed dispersal, are crucial ecological interactions that maintain the structure and diversity of natural communities. Although many studies suggest the importance of mutualism, empirical evidence for community-level impacts of mutualists has remained anecdotal, and the central role of mutualism, relative to other species interactions, has long been debated in the theoretical literature. Here I report the community-level consequences of a biological invasion that disrupts important seed-dispersal mutualisms. I show that invasion of South African shrublands by the Argentine ant (Linepithema humile) leads to a shift in composition of the plant community, owing to a disproportionate reduction in the densities of large-seeded plants. This study suggests that the preservation of mutualistic interactions may be essential for maintaining natural communities.

The health status of veterans using mobile clinics in rural areas.

Between 1992 and 1994, the Department of Veterans Affairs (VA) experimented with mobile clinics to provide health care for rural veterans. The objective was to assess the health status of rural mobile clinics' patients and compare this with patients receiving care in VA hospital-based clinics. This study hypothesized that hospital-based clinic patients would be more ill (i.e., have a greater reduction in health status). The Medical Outcomes Study (MOS) Short Form was used to evaluate patients' health status. Most patients sought care for the management of chronic disease. Patients in both groups had similar types of diseases. Mobile clinic patients were as ill as hospital-based patients (i.e., similar health status scores). This study shows that rural veterans have a case mix and a reduction in health status similar to that of VA hospital-based patients. Planners should account for this health reduction when planning the kinds of facilities and services needed in rural areas.

Evaluation of the VA mobile clinics demonstration project.

In 1988 the Veterans' Benefits and Services Act attempted to solve the problem of the lack of adequate VA healthcare facilities in rural areas by establishing a demonstration program using mobile clinics. Six clinics operated in areas that were at least 100 miles from a VA healthcare facility during the time period between October 1, 1992 and May 28, 1994. This article evaluated the effect of the mobile clinics' structural limitations on clinical care, the increased number of sites on VA usage, and cost. Limited space for storage of medical records and the unavailability of laboratory, electrocardiographic, or radiographic facilities significantly affected clinical practice. However, even with these space limitations, veterans' use of healthcare in the areas served by the mobile clinics increased significantly in comparison to reference areas. The direct costs per visit averaged more than three times what the VA would have reimbursed the private sector.