The Changing Demography of Late-Life Family Caregiving: A Research Agenda to Understand Future Care Networks for an Aging U.S. Population

Repeated claims that a dwindling supply of potential caregivers is creating a crisis in care for the U.S. aging population have not been well-grounded in empirical research. Concerns about the supply of family care do not adequately recognize factors that may modify the availability and willingness of family and friends to provide care to older persons in need of assistance or the increasing heterogeneity of the older population. In this paper, we set forth a framework that places family caregiving in the context of older adults' care needs, the alternatives available to them, and the outcomes of that care. We focus on care networks, rather than individuals, and discuss the demographic and social changes that may alter the formation of care networks in the future. Last, we identify research areas to prioritize in order to better support planning efforts to care for the aging U.S. population.

A Care Paradox: The Relationship Between Older Adults' Caregiving Arrangements and Institutionalization and Mortality

We investigate how the type of caregiving arrangement is associated with older Americans' outcomes. We use the Health and Retirement Study (2004-2018) and discrete-time event history analysis to assess the odds of institutionalization or death over a 14-year period among older adults with limitations in Activities of Daily Living (ADLs; e.g., bathing). We consider caregiving arrangements as conventional (i.e., spouse or adult child), unconventional (e.g., extended family, employee, friend), or self-directed (i.e., no caregiver). We find a "care paradox" in that self-directing one's own care was associated with a lower risk of institutionalization or death compared with having conventional care (spouse/adult caregiver) and unconventional care (employee). Relative to conventional care, having an employee caregiver was associated with increased risk of institutionalization. Findings are still observed when controlling for level of impairment and various health-related factors. More research is needed to understand older adults who self-direct their own care.

Family Ties and Older Adult Well-Being: Incorporating Social Networks and Proximity

OBJECTIVES

This paper examines the family ties of older adults in the United States and how they are associated with mental health and social activity. We compare older adults with 4 types of family ties: adults "close" to family in proximity and social network, "kinless" older adults without a partner or children, "distanced" adults who live far from close kin, and "disconnected" older adults who do not report kin in their social network or do not report a location for some kin.

METHODS

Using pooled data from the National Health and Aging Trends Study 2015-2019 for older adults aged 70 and older (N = 24,818 person-waves), we examine how family ties are associated with mental health and social activity, and whether lacking family is tied to poor well-being because older adults' needs are not being met.

RESULTS

Kinless older adults and disconnected older adults have poorer outcomes (lower mental health scores and less social activity), compared to those close to their family. These findings suggest that both the presence and quality of the connection, as measured here via both location and social network, are critical for understanding which older adults are "at risk." Older adults who were not geographically proximate to their close kin (i.e., distanced) were not disadvantaged relative to those close to their families. Unmet needs do not help explain these patterns.

DISCUSSION

Our results highlight that family ties are important for older adults well-being, not just through their existence but also their quality and strength.

Caregiving and Self-Esteem in Mid and Later Life: Is There Variation by Age, Parental Status, and Gender?

Caregiving may prove either beneficial or harmful for caregiver well-being, depending on the circumstances surrounding care provision. Using data from the two most recent waves of the National Survey of Midlife Development in the United States (MIDUS, 2004-2014; N = 1,100), we examine whether providing care for an adult at both time points (i.e., 8-10 years apart) is associated with changes to self-esteem over the ten-year period, in comparison with providing care at only one time point, or not at all. We also examine moderation by caregivers' age, parental status, and gender. Findings indicated (1) caregiving at both waves was associated with decreases in self-esteem among younger and midlife adults, but this effect weakened and even reversed with age; and (2) caregiving at both waves was associated with increased self-esteem among participants without children, but not among those with children. We discuss implications for identifying caregivers at greatest risk of diminished well-being.

Shared Care Networks Assisting Older Adults: New Insights From the National Health and Aging Trends Study

BACKGROUND AND OBJECTIVES

Caregiving research often assumes older adults receiving care have a primary caregiver who provides the bulk of care. Consequently, little is known about the extent to which care responsibilities are shared more evenly within a care network, the characteristics associated with sharing, or the consequences for meeting older adults' care needs.

RESEARCH DESIGN AND METHODS

We analyze a sample of U.S. older adults receiving care from the 2011 National Health and Aging Trends Study (n = 2,398). Based on variables reflecting differences in care hours, activities, and care provided by the whole network, we create network typologies for those with two or more caregivers (n = 1,309) using K-means cluster analysis. We estimate multinomial and logistic regression models to identify factors associated with network type and the association between type and unmet needs. We conduct analyses overall and for older adults living with and without dementia.

RESULTS

Analyses reveal four network types: Small, low-intensity shared care network (SCN); large, moderate-intensity SCN; small, low-intensity primary caregiver network (PCN); and moderate-sized, high-intensity PCN. Among all older adults receiving care, 51% have a sole caregiver, 20% have an SCN with no primary caregiver, and 29% have a PCN. Among older adults with dementia receiving intense care, unmet needs are lower among those with an SCN (vs. PCN).

DISCUSSION AND IMPLICATIONS

Findings underscore that the primary caregiver construct, although common, does not apply to a substantial share of care networks. Moreover, having an SCN when needs are high may be beneficial to meeting older adult's needs.

Work as Overload or Enhancement for Family Caregivers of Older Adults: Assessment of Experienced Well-Being Over the Day

Objective

This study examines work and care patterns and their association with experienced well-being over the course of the day and tests a moderating effect of gender.

Background

Many family and unpaid caregivers to older adults face dual responsibilities of work and caregiving. Yet little is known about how working caregivers sequence responsibilities through the day and their implications for well-being.

Method

Sequence and cluster analysis is applied to nationally representative time diary data from working caregivers to older adults in the U.S. collected by the National Study of Caregiving (NSOC) (N=1,005). OLS regression is used to test the association with well-being and a moderating effect of gender.

Results

Among working caregivers, five clusters emerged, referred to as: Day Off, Care Between Late Shifts, Balancing Act, Care After Work, and Care After Overwork. Among working caregivers, experienced well-being was significantly lower among those in the Care Between Late Shifts and Care After Work clusters relative to those in the Day Off cluster. Gender did not moderate these findings.

Conclusion

The well-being of caregivers who split time between a limited number of hours of work and care is comparable to those who take a day off. However, among working caregivers balancing full-time work - whether day or night - with care presents a strain for both men and women.

Implications

Policies that target full-time workers who are balancing care for an older adult may help increase well-being.

The Social Cost of Providing Care to Older Adults With and Without Dementia

OBJECTIVES

Social participation is known to enhance well-being. Caregiving responsibilities are more intense when caring for an older adult with than without dementia and may affect caregivers' ability for social participation. We estimate social participation restrictions among caregivers for older persons with versus without dementia, variation within racial/ethnic group, and the mediating effect of care hours.

METHODS

We use the 2017 National Health and Aging Trends Study (NHATS) and National Study of Caregiving (NSOC) to study family caregivers for older adults. We estimate the prevalence of social participation (e.g., visiting family/friends, religious activities, group/club activities, going out) that were important to the caregiver but missed due to caregiving. We use logistic models to test for differences in restrictions by the older adult's dementia status overall and within race/ethnic group, adjusting for caregiver and care receiver characteristics.

RESULTS

One-third of family caregivers for older adults with dementia reported restrictions due to caregiving, double the prevalence among caregivers of an older adult without dementia (33.3% vs 16.0%; p < .001). This doubling gap persisted in adjusted models (odds ratio [OR] = 2.4; p < .01) but mainly for White, non-Hispanic caregivers (OR = 3.2; p < .001). Substantially greater caregiving hours for people with versus without dementia was found (104 vs 60 hr per month), which is responsible for about 21% of the total difference in restrictions (p < .05).

DISCUSSION

More time spent among caregivers of persons with versus without dementia may be an important factor undermining social participation, but hours only partially explain the gap. Future interventions should consider how to facilitate social participation among caregivers.

Cohabiting Adult Children's Transfers to Parents in the United States

Objective

This brief report presents national estimates of transfers of time and money from cohabiting adult children (ages 18 to 65) to their parents (own and in-laws) to test whether cohabiting adults give differently from their counterparts.

Background

Previous U.S. studies use data collected in the late 1980s and mid-1990s, when cohabitation was an emerging family form; they find mixed results. Rising rates of cohabitation and an aging population of parents who may rely on transfers from adult children necessitate updated estimates that can help develop the theory of institutionalization of cohabitation.

Method

This study used the 2013 Panel Study of Income Dynamics (PSID) Rosters and Transfers Module, a sample of U.S. households (N=6,340), and logistic and negative binomial models to estimate the likelihood of giving any time or any money to parents by the respondent's union status, the amounts given, and parent type (own, in-laws).

Results

Cohabitors were less likely to give time to their own parents than their never married counterparts, and gave fewer hours, but were more likely to give time and gave more hours than married adults. For financial transfers to own parents, cohabitors and married respondents gave similarly, but both were less likely to give any money than are single respondents. Cohabitators gave more hours to their in-laws than married respondents.

Conclusion

Cohabitors behave somewhere in-between marital "greedy institution" norms and broader norms of solidarity with parents. More work should be done to understand how union status affects transfers to parents.

Educational Attainment Differences in Attitudes toward Provisions of IADL Care for Older Adults in the U.S

Educational attainment is increasingly associated with family inequality in the U.S., but there is little understanding about whether and how education stratifies attitudes toward eldercare. Using the General Social Survey 2012 Eldercare Module, I test the association between educational attainment and attitudes toward eldercare provisions of Instrumental Activities of Daily Living (IADL) including different combinations of help and payment for help. IADLs are the most common care received by older adults and needs are projected to grow, so understanding attitudes toward this type of care is timely and relevant. Results show that adults with a bachelor's degree or graduate/professional degree, compared to adults with less than a high school degree, are more likely to support complete family IADL eldercare, where families provide the care and any payment necessary for care, compared to complete outside IADL eldercare, where outside institutions provide both care and payment. Educational attainment is an important axis of stratification in the U.S. and may explain potentially bifurcated policy solutions desired among different groups.

Feeling the Squeeze

People often provide caregiving to other family members across the life course. "Sandwiched" caregiving, or caring for a child and aging parent at the same time, is a common form of combining care duties. However, adults share more years of life with many different family members due to population level demographic shifts in life expectancy and family formation. This shift means that multigenerational care, or providing for two or more different generations of family members simultaneously, may better reflect the reality of caregiving for contemporary cohorts of adults. Although there is strong public backing for providing supports to caregivers, current policies are often limited.

A day in the life of caregivers to older adults with and without dementia: Comparisons of care time and emotional health

INTRODUCTION

How care-related time and emotional health over the day differ for those assisting older adults with and without dementia is unclear.

METHODS

Using 2134 time diaries from the National Study of Caregiving, we compared emotional health and care time for caregivers of older adults with and without dementia.

RESULTS

Caregivers to older adults with dementia experienced worse (higher scores) on a composite measure of negative emotional health (4.2 vs 3.3; P < .05) and provided more physical/medical care (33.7 vs 16.2 minutes; P < .05) and less transportation assistance (12.6 vs 24.8 minutes; P < .05) than other caregivers. In models, providing physical/medical care was associated with worse emotional health (β = 0.15; P < .01) and socializing with the care recipient was associated with worse emotional health when the recipient had dementia (β = 0.28; P < .01).

DISCUSSION

Findings highlight the opportunity for targeted interventions to address the emotional consequences of different types of care time in the context of dementia.

Greater Inclusion of Asian Americans in Aging Research on Family Caregiving for Better Understanding of Racial Health Inequities

With the substantial demographic changes in racial composition in the United States since 1965, research on racial health inequities must build upon the Black-White binary to assess the complex ways "race" affects health and aging. Considering variation in the prevalence and meanings of aging across racialized groups requires concerted efforts to expand and disaggregate samples. Aligned with the goals of the intersectionality framework, we argue that greater inclusion of Asian Americans is critical to advance both theoretical and methodological considerations that enable us to investigate the lived experiences of Asian Americans. Using caregiving as an example, we discuss how systemic, cultural, and interpersonal marginalization from racism and other oppressive systems intertwine with "race" to produce the race effects. Greater inclusion of Asian Americans helps further provide the opportunity to conceptualize culture as dynamic and interacting with structure to produce different racial patterns. Meaningful inclusion of Asian Americans in research requires more systemic effort to collect accurate, reliable, and quality data for Asian Americans that can be disaggregated by other important axes of stratification.

Co-residence beliefs 1973-2018: Older adults feel differently than younger adults

Objective

This brief study examines support for co-residence (i.e. aging parents living with their adult children), and how age predicts support for this belief considering the rapidly aging U.S. population.

Background

Co-residence, a form of intergenerational transfer between family members, can help facilitate care for aging parents as well as help older adults age in the community. Support for this type of co-residence was on the rise in the 1970s and 1980s.

Method

Support for co-residence of older adults living with their adult children is estimated using 36,843 responses from the U.S. General Social Survey from 1973 to 2018. Descriptive analyses, logistic regression, and decomposition analyzes are used to test explanatory factors in trends, focusing on differences for older (age 65 and older) vs. younger (under 65) respondents.

Results

Older adults are less supportive than younger adults of co-residence even as support has generally increased across time. Decomposition results show that a little over half of the difference between younger and older adults is explained by cohort replacement, with two-fifths of the difference unexplained by social or demographic factors.

Conclusion

Findings suggest that although cohort replacement has contributed to an attitude shift over time, important age differences in attitudes remain. Older adults are less supportive of co-residence than younger adults.

Care Received and Unmet Care Needs Among Older Parents in Biological and Stepfamilies

OBJECTIVES

Increased likelihood of having stepchildren among more recent cohorts of older adults, alongside lower levels of assistance from stepchildren, have led to concerns about greater unmet needs for older parents in stepfamilies. However, few studies have directly examined family structure and unmet needs. We examined the associations between having stepchildren (vs. only biological children) and receiving care from adult children, and unmet needs for assistance.

METHODS

Using the 2015 National Health and Aging Trends Study, we investigated among older parents with care needs whether levels of care received from adult children and unmet needs differed between those with biological versus step families. We also explored whether partner or paid care compensated for observed differences.

RESULTS

Older parents in need of care were more than twice as likely to receive care from their adult children if they had biological instead of step families. Unmet needs among older parents did not differ by family structure, nor did levels of partner or paid care.

DISCUSSION

Results illustrate that concerns about the implications of the rising prevalence of stepfamilies for care parents receive from their children may be warranted. However, there is a lack of evidence of greater unmet need for care for older parents in stepfamilies, as risks of unmet needs are high for older parents regardless of family type.

Family embeddedness and older adult mortality in the United States

Do different operationalizations of family structure offer different understandings of the links between family structure and older adult mortality? Using the American Health and Retirement Study (N = 29,665), we examine mortality risks by three measures of family structure: whether respondents have different family statuses (e.g. married vs. unmarried), volume of family members available (e.g. having one vs. two living immediate family members), and family embeddedness (e.g. having neither spouse nor child vs. having spouse but no child). We focus on three kin types: partner/spouse, children, and siblings. We find that differences in empirical estimates across measures of family structure are not dramatic, but that family embeddedness can show some additional heterogeneity in mortality patterns over family status variables or the volume of ties. This paper tests different ways of operationalizing family structure to study mortality outcomes and advances our understanding of how family functions as a key social determinant of health.

Intergenerational Relationships, Family Caregiving Policy, and COVID-19 in the United States

Families and intergenerational relationships are important sources of risk for COVID-19 infection, especially for older adults who are at high risk of complications from the disease. If one family member is exposed to the virus they could serve as a source of transmission or, if they fall ill, the resources they provide to others could be severed. These risks may be especially heightened for family members who work outside the home and provide care, or for those family members who care for multiple generations. Policies have the potential to help families bear the burden of these decisions. This essay argues that policies that address health, employment, and other social issues have implications for families, and that policies aimed at families and caregivers can affect the health, employment, and the general well-being of the nation.

Linked Lives and Childhood Experience of Family Death on Educational Attainment

Sociological theory and research suggest that experiencing family members' deaths during childhood and adolescence is an important event subject to significant disparities. Previous research links immediate family members' deaths to poor life outcomes, but it considers a limited set of family members and has not tested the association of family member death with educational attainment. This study estimates the rates and educational impacts of experiencing the deaths of immediate (siblings, parents) and extended family members (aunts and uncles, cousins, and grandparents) during childhood and adolescence for Black and White Americans. We find that family death is associated with educational attainment, but the associations differ by family member type and gender, and child's race. Experiences of family death are unequally distributed by race and demonstrate complex associations with educational attainment. This research broadens life course and family systems theory by incorporating childhood family experiences of death on adult educational attainment and stratification.

Beyond Household Walls: The Spatial Structure of American Extended Kinship Networks

How far do Americans live from their close and extended kin? The answer is likely to structure the types of social, instrumental, and financial support that they are able to provide to one another. Based on the Panel Study of Income Dynamics, kin pairs vary widely in odds of household co-residence, co-residence in the same administrative units, and inter-tract distances if they do not live in the same census tract. Multivariate regression tests show that family structure, educational attainment, and age are closely associated with kin proximity. Fixed effects models demonstrate that fam ily formation shapes spatial relations between kin.

Mothers' Time and Relationship with Their Adolescent Children: The Intersecting Influence of Family Structure and Maternal Labor Force Participation

We investigate whether the anticipated risks of increasing maternal work hours for mother-adolescent relationships differ across family structures: Do intensive mothering norms exacerbate these risks particularly for mothers in two-parent biological families or does their partners' greater involvement significantly mitigate these risks? We predict mothers' accessible time, engaged time, and the quality of their relationship with their adolescent children using the National Study of Adolescent to Adult Health. Although the association between mothers' labor force participation and mothers' accessible time is significantly weaker in stepfather families relative to two-parent biological families, family structure does not moderate the associations between mothers' labor force participation and mother's engaged time or the quality of her relationship with her adolescent. We conclude that mothers face strong normative pressure to privilege their relationship with their child even in the face of long work hours and weaker family support.

GENDER AND THE MBA: Differences in Career Trajectories, Institutional Support, and Outcomes

This study asks how men's and women's careers diverge following MBA graduation from an elite university, using qualitative interview data from 74 respondents. We discover men and women follow three career pathways post-graduation: lockstep (stable employment), transitory (3 or more employers), and exit (left workforce). While similar proportions of men and women followed the lockstep pathways and launched accelerated careers, sizable gender differences emerged on the transitory pathway; men's careers soared as women's faltered on this path-the modal category for both. On the transitory path, men fared much better than women when moving to new organizations, suggesting that gender may become more salient when people have a shorter work history with a company. Our findings suggest that clear building blocks to promotions reduce gender bias and ambiguity in the promotion process, but multiple external moves hamper women, putting them at a clear disadvantage to men whose forward progress is less likely to be stalled by such moves.

Single-parent households and mortality among children and youth

Although many studies have examined associations between family structure and child outcomes, few have considered how the increase in single-parent households since the 1960s may have affected child mortality rates. We examined state-level changes in the percentage of children living with single parents between 1968 and 2010 and state-level trends in mortality among children and youth (age 19 or younger) in the United States. Regression models with state and year fixed effects revealed that increases in single parenthood were associated with small increments in accidental deaths and homicides.

Assessing Spatial and Temporal Differences in State-Level Child Well-Being Based on Tests of Statistical Significance

The concept of child well-being is central to the study of children and are reflected in data books, statistical indices, and report cards. Statistical indicators of child well-being are increasingly used to examine the quality of life for children. Such reports are often used to examine differences across geographic areas (spatial differences) and changes over time (temporal differences). In this study, indicators from a widely used report on child well-being are used to compare spatial differences and temporal differences among states in the U.S. based on tests of statistical significance. Results show that currently available indicators are better at detecting differences in child well-being between states at one point in time rather than state-level changes over time. Additionally, a state index of child well-being is constructed using only indicators that are statistically significant different than the national rate; the results of the new index proved to be similar to the more traditional z-score method.

Assessment of the sensitivity of three North American fish species to disruptors of steroidogenesis using in vitro tissue explants

There is concern regarding exposure of aquatic organisms to chemicals that interfere with the endocrine system. One critical mechanism of endocrine disruption is impairment of steroidogenesis that can lead to altered hormone levels, altered or delayed sexual development, and ultimately reproductive failure. With the current large gap in knowledge and a high degree of uncertainty regarding the sensitivity of fishes native to northern ecosystems to endocrine disrupting chemicals (EDCs), the aim of this study was to develop an in vitro gonadal explant assay enabling the assessment of EDCs on sex-steroid production in wild fish species native to North America. Northern pike (Esox lucius), walleye (Sander vitreus), and white sucker (Catostomus commeroni) were sampled from a reference location in Lake Diefenbaker, Saskatchewan, Canada, at spawn and multiple post-spawn time points. Gonads were excised and immediately exposed for 24h to a model inducer (forskolin) or inhibitor (prochloraz) of steroidogenesis in L-15 supplemented media. Furthermore, seasonal profiles of plasma 11-ketotestosterone (11-KT) and 17-β estradiol (E2) concentrations were characterized. Enzyme-linked immunosorbent assays were used to quantify hormone concentrations in plasma and media. The seasonal profile of plasma hormones was significantly correlated with basal in vitro hormone production. Gonad tissue exposed to forskolin showed a concentration-dependent increase in E2 and a general increase in 11-KT. Gonad tissue exposed to prochloraz resulted in a decrease of concentrations of 11-KT and E2. These results illustrated that gonadal tissue is undergoing steroidogenesis in an in vitro setting that is comparable to in vivo hormone profiles, and which is responsive to chemical exposure in a concentration-dependent manner. The seasonal time point during which gonad explants were excised and exposed had an impact on the potency and magnitude of responses, resulting in a seasonal effect on sensitivity. Male and female white sucker showed greatest sensitivity to forskolin, while male and female walleye showed greatest sensitivity to prochloraz. Also, gonad explants from these species were found to have greater sensitivity than responses previously reported for in vitro explants of other fish species such as the fathead minnow (Pimephales promelas), and stable cell lines currently used as screening applications to detect chemicals that might disrupt the endocrine system. Therefore, current approaches that use stable cell lines or tissue explants from standardized small bodied laboratory species might not be protective of some wild fish species. Future research is required that investigates whether this in vitro gonadal explant assay is predictive of in vivo effects in wild species of fishes.

Seasonal pasture myopathy/atypical myopathy in North America associated with ingestion of hypoglycin A within seeds of the box elder tree

REASONS FOR PERFORMING STUDY

We hypothesised that seasonal pasture myopathy (SPM), which closely resembles atypical myopathy (AM), was caused by ingestion of a seed-bearing plant abundant in autumn pastures.

OBJECTIVES

To identify a common seed-bearing plant among autumn pastures of horses with SPM, and to determine whether the toxic amino acid hypoglycin A was present in the seeds and whether hypoglycin metabolites were present in SPM horse serum or urine.

METHODS

Twelve SPM cases, 11 SPM pastures and 23 control farms were visited to identify a plant common to all SPM farms in autumn. A common seed was analysed for amino acid composition (n = 7/7) by GC-MS and its toxic metabolite (n = 4/4) identified in conjugated form in serum [tandem mass spectrometry (MS/MS)] and urine [gas chromatography (GC) MS]. Serum acylcarnitines and urine organic acid profiles (n = 7) were determined for SPM horses.

RESULTS

Seeds from box elder trees (Acer negundo) were present on all SPM and 61% of control pastures. Hypoglycin A, known to cause acquired multiple acyl-CoA dehydrogenase deficiency (MADD), was found in box elder seeds. Serum acylcarnitines and urine organic acid profiles in SPM horses were typical for MADD. The hypoglycin A metabolite methylenecyclopropylacetic acid (MCPA), known to be toxic in other species, was found in conjugated form in SPM horse serum and urine. Horses with SPM had longer turn-out, more overgrazed pastures, and less supplemental feeding than control horses.

POTENTIAL RELEVANCE

For the first time, SPM has been linked to a toxin in seeds abundant on autumn pastures whose identified metabolite, MCPA, is known to cause acquired MADD, the pathological mechanism behind SPM and AM. Further research is required to determine the lethal dose of hypoglycin A in horses, as well as factors that affect annual seed burden and hypoglycin A content in Acer species in North America and Europe.

Generality of vertebrate developmental patterns: evidence for a dermomyotome in fish

The somitic compartment that gives rise to trunk muscle and dermis in amniotes is an epithelial sheet on the external surface of the somite, and is known as the dermomyotome. However, despite its central role in the development of the trunk and limbs, the evolutionary history of the dermomyotome and its role in nonamniotes is poorly understood. We have tested whether a tissue with the morphological and molecular characteristics of a dermomyotome exists in nonamniotes. We show that representatives of the agnathans and of all major clades of gnathostomes each have a layer of cells on the surface of the somite, external to the embryonic myotome. These external cells do not show any signs of terminal myogenic or dermogenic differentiation. Moreover, in the embryos of bony fishes as diverse as sturgeons (Chondrostei) and zebrafish (Teleostei) this layer of cells expresses the pax3 and pax7 genes that mark myogenic precursors. Some of the pax7-expressing cells also express the differentiation-promoting myogenic regulatory factor Myogenin and appear to enter into the myotome. We therefore suggest that the dermomyotome is an ancient and conserved structure that evolved prior to the last common ancestor of all vertebrates. The identification of a dermomyotome in fish makes it possible to apply the powerful cellular and genetic approaches available in zebrafish to the understanding of this key developmental structure.

The embryo MADS domain factor AGL15 acts postembryonically. Inhibition of perianth senescence and abscission via constitutive expression

AGL15 (AGAMOUS-like 15), a member of the MADS domain family of regulatory factors, accumulates preferentially throughout the early stages of the plant life cycle. In this study, we investigated the expression pattern and possible roles of postembryonic accumulation of AGL15. Using a combination of reporter genes, RNA gel blot analysis, and immunochemistry, we found that the AGL15 protein accumulates transiently in the shoot apex in young Arabidopsis and Brassica seedlings and that promoter activity is associated with the shoot apex and the base of leaf petioles throughout the vegetative phase. During the reproductive phase, AGL15 accumulates transiently in floral buds. When AGL15 was expressed in Arabidopsis under the control of a strong constitutive promoter, we noted a striking increase in the longevity of the sepals and petals as well as delays in a selected set of age-dependent developmental processes, including the transition to flowering and fruit maturation. Although ethylene has been implicated in many of these same processes, the effects of AGL15 could be clearly distinguished from the effects of the ethylene resistant1-1 mutation, which confers dominant insensitivity to ethylene. By comparing the petal breakstrength (the force needed to remove petals) for flowers of different ages, we determined that ectopic AGL15 had a novel effect: the breakstrength of petals initially declined, as occurs in the wild type, but was then maintained at an intermediate value over a prolonged period. Abscission-associated gene expression and structural changes were also altered in the presence of ectopic AGL15.

Prevention of sodium lauryl sulfate irritant contact dermatitis by Pro-Q aerosol foam skin protectant

Eczematous skin disease is a serious work-related illness. Since 1995, reimbursement by insurance companies for treatment of skin diseases has become the largest cost source in some countries. This study was a randomized controlled trial (N = 20) of the efficacy of Pro-Q, a skin protectant product, in the prevention of contact dermatitis from sodium lauryl sulfate and urushiol, the resinous sap of poison ivy and poison oak. Pro-Q was significantly effective in reducing the irritation from sodium lauryl sulfate but did not prevent the allergic reaction to urushiol.

Intercalation of ethidium and analogues with nucleic acids: a molecular orbital study

Semiempirical calculations suggest that the intercalation complexes of phenanthridinium cations 1-4 with G-C/C-G and 1 with A-U/U-A are stabilized by frontier orbital interactions between the LUMO of the intercalator and the HOMOs of the adjacent purine bases. The charge on the ring nitrogen of 1-4 appears to be necessary for the orbital interactions, lowering the LUMO, facilitating mixing of this orbital with the HOMOs of the adjacent purine bases to give an extended HOMO stabilizing the complex and resulting in the bathochromic shift in the electron absorption spectrum. Noncationic phenanthridine 5 shows no frontier orbital interactions in the forced intercalation complex with G-C/C-G. The results of the calculations parallel experimental T(m) values.

The TMK1 gene from Arabidopsis codes for a protein with structural and biochemical characteristics of a receptor protein kinase

Genomic and cDNA clones that code for a protein with structural and biochemical properties similar to the receptor protein kinases from animals were obtained from Arabidopsis. Structural features of the predicted polypeptide include an amino-terminal membrane targeting signal sequence, a region containing blocks of leucine-rich repeat elements, a single putative membrane spanning domain, and a characteristic serine/threonine-specific protein kinase domain. The gene coding for this receptor-like transmembrane kinase was designated TMK1. Portions of the TMK1 gene were expressed in Escherichia coli, and antibodies were raised against the recombinant polypeptides. These antibodies immunodecorated a 120-kD polypeptide present in crude extracts and membrane preparations. The immunodetectable band was present in extracts from leaf, stem, root, and floral tissues. The kinase domain of TMK1 was expressed as a fusion protein in E. coli, and the purified fusion protein was found capable of autophosphorylation on serine and threonine residues. The possible role of the TMK1 gene product in transmembrane signaling is discussed.

Synthesis and quantitative structure-activity relationship analysis of 2-(aryl or heteroaryl)quinolin-4-amines, a new class of anti-HIV-1 agents

Thirty-eight 2-(aryl or heteroaryl)quinolin-4-amines, N,N-disubstituted, N-monosubstituted, and without a substituent at the amino group have been synthesized with use of novel chemistries developed by us recently. Some of these derivatives show anti-HIV-1 activity at a concentration level of 1 microM and low cell toxicity in vitro. The most active and least toxic compounds are derivatives of 2-(3-pyridyl)quinoline. The results of the quantitative structure-activity relationship analyses, including several classical, linear regression correlations and a Free-Wilson approach of de novo model, provide guidelines for the design of new active compounds of this class.

One-month inhalation toxicity study of tulobuterol hydrochloride in rats and dogs

Tulobuterol hydrochloride (HCl) has beta 2-adrenergic agonist activity and is under development for use in the treatment of chronic obstructive lung disease. The purpose of this study was to determine the toxicity of inhaled tulobuterol HCl in rats and dogs. Rats were whole-body exposed to aerosol gravimetric concentrations of 0, 0.03, 0.22, or 1.1 mg/liter of tulobuterol HCl, 60 min/day for 28 days. Dogs were exposed (via insufflation) to estimated daily doses of 0, 0.2, 1.0, or 6.0 mg/kg for an equal period. Plasma levels of tulobuterol were determined following exposure on Days 1, 8, and 28 using a high-pressure liquid chromatographic method developed for this study. Results indicated that plasma tulobuterol levels were highly correlated with tulobuterol doses (p less than 0.001 for rats and dogs). No dose-related changes in body weight food consumption, hematological, or serum chemistry parameters were observed in either species. Anterior nasal cavity lesions were observed by light microscopy in rats exposed to 0.22 and 1.1 mg/liter tulobuterol HCl at an incidence of 14 and 93%, respectively. These lesions involved the nasal septum, turbinates, and/or the dorsolateral wall of the nasal cavity and consisted of suppurative rhinitis and necrosis. The corresponding mean plasma tulobuterol levels on Day 28 in mid- and high-dose rats were approximately 1000 and 15,000 ng/ml. Nasal lesions were not observed in rats allowed to recover for 2 weeks. No gross or microscopic lesions were detected in lungs or other tissues of either species.(ABSTRACT TRUNCATED AT 250 WORDS)

The hemodynamic and clinical responses to terazosin, a new alpha blocking agent, in congestive heart failure

To determine the hemodynamic effects of a new alpha 1 blocker, terazosin, in congestive heart failure, six patients with this condition underwent hemodynamic testing (at rest and during exercise) before and after dosing. Doses of 2, 5, and 10 mg were examined in sequence over 3 days to define dose-response characteristics. Terazosin, in these doses, decreased pulmonary and systemic vascular resistances and right atrial and pulmonary capillary wedge pressures. Terazosin increased stroke volume and cardiac output, presumably through afterload-reduction, without altering heart rate. These aforementioned responses were apparent both at rest and during exercise. While a direct relationship existed between dose and plasma concentration, a similar relationship was not observed for dose (or plasma concentration) and hemodynamic response; no differences were noted between the hemodynamic responses to the three doses. Improvement in hemodynamics persisted and the clinical status and exercise capacity improved in the four patients chronically treated (over 2 months) with terazosin. Treating the heightened tone of the sympathetic nervous system in congestive heart failure with the alpha 1 blocker, terazosin, may be of benefit to some patients afflicted with this disorder.

Terazosin kinetics after oral and intravenous doses

Terazosin kinetics were followed in normal subjects after intravenous doses of 0.5, 1.0, and 2.0 mg and oral doses of 1.0 mg. Plasma and urine samples were collected for the first 48 and 24 hours. The samples were analyzed by a sensitive HPLC assay developed in our laboratory. Mean calculated peak plasma levels from the 0.5, 1.0, and 2.0 mg intravenous doses were 25.0, 44.1, and 83.3 ng/ml. After a 1 mg oral dose the mean peak level was 19.6 ng/ml. Data were fit to a two-compartment open model with mean elimination phase t1/2 values of 7.9, 8.9, and 10.1 hours for the ascending intravenous doses and 11.6 hours for the oral dose. Mean 0 to 24-hour urinary recovery after the intravenous doses was 14%, 13%, and 11%. It is concluded that terazosin kinetics are linear after oral and intravenous doses.

Hepatic drug metabolism in rats with experimental chronic renal failure

The activities of several hepatic microsomal, mitochondrial, and cytosolic drug-metabolizing enzymes, as well as the components of the cytochrome P-450 system, were determined in vitro for control, sham-operated, and uremic rats. Chronic renal failure (CRF) was produced by a two-stage surgical procedure. In this model, the animals were maintained for 21 days postoperatively before assay. During this time, serum urea nitrogen (SUN) levels rose from control levels of 21 mg/dl to an average of 63 mg/dl. Enzymes assayed included microsomal N-, O-, and S-demethylases, esterase, and UDP-glucuronyl transferase; monoamine oxidase; and alcohol dehydrogenase. CRF caused decreases of 24-32% in N- and O-demethylase activities, while S-demethylase, esterase, UDP-glucuronyl transferase, and monoamine oxidase activities were not altered significantly. Alcohol dehydrogenase activity was increased 71%. In addition, the functional components of the microsomal mixed-function oxidase system were assayed. CRF caused a 26% decrease in cytochrome P-450 levels, as compared to sham-operated controls, but cytochrome b5 and NADPH-cytochrome c (P-450) reductase were not altered. CRF caused an increase in hexobarbital sleeping time of more than 7-fold. In each case, alterations in enzyme activities or cytochrome P-450 correlated with the extent of renal failure, as determined by elevated SUN levels.

Nitrofurantoin disposition

Nitrofurantoin (50 mg) was administered in a three-way random crossover design to six healthy men. After a 45-min intravenous infusion the plasma concentration data could be described by a two-compartment open-body model with a terminal t 1/2 of 58.1 +/- 15 min. Oral availability of a tablet was 0.87 +/- 0.13 on a fasting stomach and 0.94 +/- 0.13 when taken with food. Although absorption appeared to be complete, the absorption rate profile was complex and erratic. Two subjects failed to achieve the minimum effective urine concentration of 32 micrograms/ml. After the intravenous infusion 47 +/- 13% of the dose was excreted unchanged in the urine and 1.2 +/- 0.3% was recovered as the reduced metabolite aminofurantoin.