How Well Can You Tailor the Charge of Lipid Vesicles?

Knowledge and control of surface charge or potential is important for tailoring colloidal interactions. In this work, we compare widely used zeta potential (ζ) measurements of charged lipid vesicle surface potential to direct measurements using the surface force apparatus (SFA). Our measurements show good agreement between the two techniques. On varying the fraction of anionic lipids dimyristoylphosphatidylserine (DMPS) or dimyristoylphosphatidylglycerol (DMPG) mixed with zwitterionic dimyristoylphosphatidylcholine (DMPC) from 0 to 100 mol % we observed a near-linear increase in membrane surface charge or potential up to 20-30 mol % charged lipids beyond which charge saturation occurred in physiological (high) salt conditions. Similarly, in low salt concentrations, a linear increase in charge/potential was found but only up to ∼5-10 mol % charged lipids beyond which the surface charge or potential leveled off. While a lower degree of ionization is expected due to the lower dielectric constant (ε ∼ 4) of the lipid acyl chain environment, increasing intramembrane electrostatic repulsion between neighboring charged lipid head groups at higher charge loading contributes to charge suppression. Measured potentials in physiological salt solutions were consistent with predictions using the Gouy-Chapman-Stern-Grahame (GCSG) model of the electrical double layer with Langmuir binding of counterions, but in low salt conditions, the model significantly overestimated the surface charge/potential. The much lower ionization in low salt (maximum ∼1-2% of total lipids ionized) instead was consistent with counterion condensation at the bilayer surface which limited the charge that could be obtained. The strong interplay between membrane composition, lipid headgroup ionization, electrolyte concentration, and solution pH complicates exact prediction and tuning of membrane surface charge for applications. However, the theoretical frameworks used here can provide guidelines to understand this interplay and establish a range of achievable potentials for a system and predict the response to triggers like pH and salt concentration changes.

Mental and physical health of spouse caregivers: the role of personality.

Although personal resources of caregivers, such as coping skills and social support, have been shown to be important in understanding caregiver stress and health outcomes, personality traits have not previously been considered. The purpose of this study was to examine the association between the personality traits of neuroticism and dispositional optimism and mental and physical health outcomes. It was predicted that personality would have direct effects, and indirect effects through perceived stress, on health outcomes. Participants were spouse caregivers of patients diagnosed with Alzheimer's disease. Results showed that neuroticism and optimism were significantly related to mental and physical health. Furthermore, neuroticism had significant direct effects on all of the health outcomes, and substantial indirect effects, through perceived stress, on mental health outcomes. Optimism showed stronger indirect than direct effects on all health outcomes. These findings demonstrate the importance of including personality of the caregiver in theoretical and empirical models of the caregiving process.

The effect of a support and education program on stress and burden among family caregivers to frail elderly persons.

An eight-week professionally guided caregiver support group program was found to produce statistically significant reductions in anxiety, depression, and sense of burden among family caregivers to frail elderly persons living in the community. Effects were weaker four months after the intervention ended than immediately after, but reductions in anxiety and depression were still evident.

Personality and coping among caregivers of spouses with dementia.

Personality factors and coping strategies were examined among a sample of spouse caregivers. Fifty spouse caregivers of patients diagnosed with Alzheimer's disease or a related dementia completed the NEO-FFI, a personality inventory designed to measure traits identified in the five-factor trait model, and a revised measure of the Ways of Coping Checklist. Results from a series of multivariate regressions showed that personality traits explained 60% of the variance in emotion-focused coping, 30% of variance in problem-focused coping, and 15% of variance associated with social support coping. Discussion focuses on the usefulness of including personality characteristics of the caregiver in formulating models of the caregiving coping process.

Does type of disease matter? Gender differences among Alzheimer's and Parkinson's disease spouse caregivers.

PURPOSE OF STUDY: Mental health outcomes are widely reported among spouse caregivers, with wives generally faring worse than husbands. We hypothesized that gender differences would not be as strong in a cognitively intact group because caring for cognitively intact spouses may involve less severe reciprocity losses. We also examined gender differences in coping strategies within each group. DESIGN AND METHOD: 175 spouse caregivers for patients with Alzheimer's disease (AD; n = 88) and Parkinson's disease (PD; n = 87) were interviewed. Participants completed perceived stress (PSS), depression (CES-D), state anxiety (STAI, Form Y), and coping strategies (WCCL-R) measures. RESULTS: Wives in the AD group reported significantly worse mental health outcomes than husbands, while wives and husbands in the PD group showed no differences. AD caregiving wives were less likely than husbands to use problem-focused coping strategies. There were no significant gender differences in either group for social support or emotion-focused coping. IMPLICATIONS: Loss of reciprocity in marital relationships may affect women more negatively than men. Future studies that address underlying mechanisms of gender differences and focus on similar caregiving situations and contexts deserve attention.

Personality counts for a lot: predictors of mental and physical health of spouse caregivers in two disease groups.

The purpose of this study were to examine the influence of personality on mental and physical health of spouse caregivers and to determine whether there were differences in such influences depending on disease context. The disease contexts compared were Alzheimer's disease (AD) and Parkinson's disease (PD; with no coexisting dementia)--both chronic, degenerative diseases of later life. It was predicted that personality would be related to mental and physical health, directly and indirectly, and that AD caregivers would have higher levels of perceived stress and worse mental and physical health outcomes. Participants in the study were 175 caregivers (88 AD; 87 PD) living at home with their ill spouses. The data provided an excellent fit to the hypothesized model of the relationships between personality, disease group, social support, perceived stress, and mental and physical health. Seventy-eight percent of the variance in mental health was accounted for and 35% of the variance in physical health was explained. Personality had significant direct and indirect effects on mental health and significant indirect effects on physical health. As predicted, AD caregivers had significantly worse mental health than PD caregivers; however, AD caregivers had better physical health than PD caregivers, controlling for other variables in the model. These results are discussed in relation to the existing caregiving and behavioral medicine literature. Future research should include different domains of personality--states and longer term self-regulatory processes in addition to traits--to advance models of caregiving processes further.

Retinal hemorrhages as a disease parameter in Wegener's granulomatosis.

The association of Wegener's granulomatosis with retinal hemorrhages has not been described. The authors present a patient with this heretofore undescribed characteristic.

New Zealand population data at five VNTR loci: validation as databases for forensic identity testing.

Databases were developed for three New Zealand ethnic groups (Caucasian, Maori and Polynesian), at five VNTR loci (D1S7, D2S44, D4S139, D5S110 and D12S11), and validated for interpretation of forensic identity tests. A +/-2.8% sliding window was used to define the alleles at each locus and allelic frequency distributions were obtained for each locus. The conservative nature of the sliding window approach for forensic casework was demonstrated. Tests for independence of alleles within and between loci showed good agreement with the expectation of independence. Although Polynesians are known to have reduced genetic diversity at some VNTR loci, this was found not to be a concern for the present methodology. Procedures for the analysis and reporting of DNA profile results used by New Zealand forensic scientists are therefore appropriate.

Assessment of dementia patients and their families: an ecological-family-centered approach.

Demand for assessment and treatment of dementia patients and their families is expected to increase substantially by the end of this decade, considering current estimates of about 4 million dementia patients. This article guides social work practice in the assessment of dementia patients and their families using an ecological-family-centered (EFC) model of practice. A case presentation illustrates how to apply the ECF model while incorporating ethnically sensitive practice principles. The model organizes complex assessment issues that often arise when working with families of dementia patients and illustrates the significance of cultural diversity in case practice. Literature on families of dementia patients is reviewed, an intervention plan for the family system is outlined, and implications for practice are noted.

Caregiving and social support in two illness groups.

The authors analyzed whether spouse caregivers of people with noncognitive disorders such as Parkinson's disease or people with cognitive disorders such as Alzheimer's disease differed in their use and perception of social support resources. There were no differences between the groups on the Social Support Appraisal Scale. However, caregivers of spouses diagnosed with cognitive disorders were older, had fewer children, and had fewer financial resources, and their spouses had fewer years of formal education and more problems with activities of daily living. On average, caregivers of Alzheimer's patients had been dealing with their spouses' chronic illness for a significantly shorter time. Results from logistic regression analysis indicated that four variables distinguished Alzheimer's caregivers from Parkinson's caregivers: hours of assistance from family members, instrumental activities of daily living, physical activities of daily living, and availability of personal help in a crisis.

Health of spouse caregivers of dementia patients: the role of personality and social support.

Providing care to a spouse with dementia is a challenging activity. Why one spouse caregiver copes effectively whereas another becomes demoralized, unable to cope, and at heightened risk for negative health outcomes is not well understood. There is increasing evidence that individual differences associated with effects of caregiving through the subjective appraisal of the stressor are related to health outcomes. In this study, measures of social support and personality were examined to determine their influence on health outcomes for 51 spouse caregivers of dementia patients. The finding of a relationship between health outcomes and personality and social support may help practitioners target and improve interventions with dementia patients and their families.

Inconsistency in level of care assignment decisions in skilled nursing facilities.

In Arizona, a non-Medicaid state, we investigated the extent to which unregulated level of care assignments in Skilled Nursing Facilities consistently reflect level and nature of patient impairment. Using Multiple Discriminant Analysis (MDA) to develop optimal prediction functions, approximately 70 per cent of patients could be correctly classified. Factors identified by MDA as discriminating among patients at different levels of care are an Activities of Daily Living (ADL) impairment factor, and a factor defined by confusion, transitory contact with the social environment, and propensity to wander. Results are compared with those of studies using MDA to replicate Multidisciplinary Review Team (MRT) or other expert level of care assignments intended to develop patient classification functions for clinical use. MRT assignments appear to reflect patient impairment characteristics only slightly better than do unregulated institutional assignments, suggesting that such utilization review efforts may result in minimal net gains in appropriateness of placement.

Structural and operational factors affecting quality of patient care in nursing homes.

This article inquires into structural and operational characteristics of nursing homes that have predictive power for the quality of direct patient care provided to their residents. Data are from nursing homes in the Phoenix, Arizona, metropolitan area. The data were analyzed using multivariate linear regression. Findings of policy interest are that, other things equal: (1) for-profit facilities provide lower levels of care than do nonprofit facilities; and (2) distantly headquartered chain operations provide lower care levels than locally owned facilities. These factors should be considered in long-term care planning and regulation.

Comparative utilization of community based long term care services by Hispanic and Anglo elderly in a case management system.

Utilization of formal and informal supports by Hispanic and Anglo (white, non-Hispanic) elderly enrollees in a comprehensive case management system was compared. It was found that Hispanic elderly, on the average, used significantly fewer agency services than did Anglo elderly, despite a tendency to exhibit higher levels of impairment. Hispanic elderly utilized significantly higher levels of informal support, however, and this may be a mediating factor in their lower use of agency services. Policy implications of these findings are discussed.

Mesenteric panniculitis.

We have reviewed the case of a young man with an omental mass diagnosed as mesenteric panniculitis. The clinical history, physical findings, and laboratory and radiologic studies were typical of this disorder. The diagnosis was suggested by CT scan, and confirmed on surgical biopsy. Our patient has had the typically benign course seen with mesenteric panniculitis.