Financial assistance from middle-aged couples to parents and children: racial-ethnic differences.

OBJECTIVES: To examine racial-ethnic differences in the allocation of financial transfers to parents, children, and others by middle-aged couples. METHODS: Multinomial specification of alternative recipients of financial transfers, using data from the 1992 Health and Retirement Survey. RESULTS: Transfer patterns are sensitive to parental health and wealth, to children being young or in school, as well as to the donors' health and wealth. Controlling for these and other factors, including family size and structure, Blacks and Whites are the most likely, and Hispanics the least likely, to financially help their parents compared to assisting offspring. Black couples are the most likely to sacrifice their own consumption to assist parents financially. DISCUSSION: Future research on transfers should attempt to capture unmeasured noneconomic sources of variation proxied by the race-ethnicity indicator.

Teichuronic acid operon of Bacillus subtilis 168.

Sequence analysis reveals that the Bacillus subtilis 168 tuaABCDEFGH operon encodes enzymes required for the polymerization of teichuronic acid as well as for the synthesis of one of its precursors, the UDP-glucuronate. Mutants deficient in any of the tua genes, grown in batch cultures under conditions of phosphate limitation, were characterized by reduced amounts of uronate in their cell walls. The teichuronic acid operon belongs to the Pho regulon, as phosphate limitation induces its transcription. Placing the tuaABCDEFGH operon under the control of the inducible Pspac promoter allowed its constitutive expression independently of the phosphate concentration in the medium; the level of uronic acid in cell walls was dependent on the concentration of the inducer. Apparently, owing to an interdependence between teichoic and teichuronic acid incorporation into the cell wall, in examined growth conditions, the balance between the two polymers is maintained in order to insure a constant level of the wall negative charge.

mu-opioid receptor activation inhibits N- and P-type Ca2+ channel currents in magnocellular neurones of the rat supraoptic nucleus.

1. The whole-cell voltage-clamp technique was used to examine opioid regulation of Ba2+ currents (IBa) through voltage-sensitive Ca2+ channels in isolated magnocellular supraoptic neurones (MNCs). The effects of local application of mu-, delta- or kappa-opioid receptor selective agonists were examined on specific components of high voltage-activated (HVA) IBa, pharmacologically isolated by use of Ca2+ channel-subtype selective antagonists. 2. The mu-opioid receptor selective agonist, DAMGO, suppressed HVA IBa (in 64/71 neurones) in a naloxone-reversible and concentration-dependent manner (EC50 = 170 nM, Emax = 19.5 %). The DAMGO-induced inhibition was rapid in onset, associated with kinetic slowing and voltage dependent, being reversed by strong depolarizing prepulses. Low-voltage activated (LVA) IBa was not modulated by DAMGO. 3. Administration of kappa- (U69 593) or delta-selective (DPDPE) opioid receptor agonists did not affect IBa. However, immunostaining of permeabilized MNCs with an antibody specific for kappa1-opioid receptors revealed the presence of this opioid receptor subtype in a large number of isolated somata. 4. mu-opioid-induced inhibition in IBa was largely abolished after blockade of N-type and P-type channel currents by omega-conotoxin GVIA (1 microM) and omega-agatoxin IVA (100 nM), respectively. Quantitation of antagonist effects on DAMGO-induced reductions in IBa revealed that N- and P-type channels contributed roughly equally to the mu-opioid sensitive portion of total IBa. 5. These results indicate that mu-opioid receptors are negatively coupled to N- and P-type Ca2+ channels in the somatodendritic regions of MNCs, possibly via a membrane-delimited G-protein-dependent pathway. They also support a scheme in which opioids may act in part to modulate cellular activity and regulate neurosecretory function by their direct action on the neuroendocrine neurones of the hypothalamic supraoptic neucleus.

Ethanol selectively enhances the hyperpolarizing component of neocortical neuronal responses to locally applied GABA.

Local application of GABA to rat cerebral cortical neurons in brain slices elicited biphasic responses mediated via GABAA receptors. The fast component of the response, which was most apparent with somatic application of GABA, was hyperpolarizing at the normal resting membrane potential (GABAh response). The slower component could be elicited by GABA application to nearly all regions of the cell, and was depolarizing at the resting membrane potential (GABAd response). The reversal potential of evoked IPSCs recorded with whole-cell patch electrodes (-68 mV) was comparable to the reversal potential of the GABAh response (-69 mV), and was significantly different from the reversal potential of the GABAd response (-56 mV). The GABAd response was more sensitive to enhancement by pentobarbital and more readily antagonized by both bicuculline and picrotoxin than the GABAh response. Recording in bicarbonate-free buffer changed the reversal potential of the GABAd response significantly, but had no effect on the GABAh response. In contrast, superfusion with ethanol significantly enhanced the GABAh response, while having no effect on the GABAd component. Although a localized collapse of the Cl- gradient, which has been proposed to underlie the GABAd response, could explain the greater sensitivity of the GABAd response to pentobarbital and the GABAA antagonists, this could not account for the greater sensitivity of the GABAh response to ethanol. Differences in GABAA receptor subunit composition may result in the expression of dendritic and somatic GABAA receptors that have different kinetics, reversal potentials, and sensitivity to pharmacological agents, including ethanol.

Introns and intein coding sequence in the ribonucleotide reductase genes of Bacillus subtilis temperate bacteriophage SPbeta.

The two putative ribonucleotide reductase subunits of the Bacillus subtilis bacteriophage SPbeta are encoded by the bnrdE and bnrdF genes that are highly similar to corresponding host paralogs, located on the opposite replication arm. In contrast to their bacterial counterparts, bnrdE and bnrdF each are interrupted by a group I intron, efficiently removed in vivo by mRNA processing. The bnrdF intron contains an ORF encoding a polypeptide similar to homing endonucleases responsible for intron mobility, whereas the bnrdE intron has no obvious trace of coding sequence. The downstream bnrdE exon harbors an intervening sequence not excised at the level of the primary transcript, which encodes an in-frame polypeptide displaying all the features of an intein. Presently, this is the only intein identified in bacteriophages. In addition, bnrdE provides an example of a group I intron and an intein coding sequence within the same gene.

Asset and Health Dynamics Among the Oldest Old: an overview of the AHEAD Study.

This chapter provides background information for the study of Asset and Health Dynamics Among the Oldest Old (AHEAD), a prospective panel survey of persons born in 1923 or earlier who were residing in the community at the time of the 1993 baseline. Interviews were sought with both spouses in married households, and an overall total of 8,222 were completed. We review the interdisciplinary scientific issues that motivated the study, describe the fundamental design decisions that structured AHEAD, and summarize the content in the core and experimental modules. The study provides unusually detailed data on cognition, family structure and transfers, and assets. Data are presented on sample selections, response rates, and oversamples of minority groups. Basic descriptive data on the demographic, health, and socioeconomic attributes of respondents also are presented. Plans for future waves of AHEAD are described, including a next-of-kin interview for decreased respondents.

The division of family labor: care for elderly parents.

We consider the division of caregiving efforts among the children of older, functionally limited parents. Our model of parental care assumes that care decisions are made in the context of an extended family, with each child taking into account not only the parent's needs and the child's own circumstances, but also the characteristics and actual care behavior of siblings. We propose a simultaneous-Tobit statistical framework that embodies these assumptions. The model is estimated using data from the 1993 Asset and Health Dynamics Among the Oldest Old (AHEAD) study. The findings indicate that a child's hours of parent care are reduced, but on much less than a one-for-one basis, as the parent-care hours of siblings increase. We also find that a child's supply of parent-care hours is reduced by having sisters, holding constant the care efforts of siblings.

Selection of children to provide care: the effect of earlier parental transfers.

We use the first wave of data from the Asset and Health Dynamics Among the Oldest Old (AHEAD) study to examine the effects of past parent-to-child financial transfers on selection of a child to provide assistance with basic personal care for unmarried parents. We estimate a fixed-effects conditional logit model and find a positive and significant association between past financial transfers and a child's current helping behavior. The coefficient of past financial transfers is in the direction hypothesized, and its magnitude is 80% as large as that of gender, a well-documented powerful predictor of parental caregiving. There appears to be substantial evidence that earlier parent-to-child financial gifts play a role in determining which child in the family will provide assistance.

mu-Opioid receptor activation decreases N-type Ca2+ current in magnocellular neurons of the rat basal forebrain.

Opioid modulation of calcium currents was studied in acutely dissociated rat basal forebrain neurons using the whole cell patch-clamp recording technique. The mu-opioid receptor agonist DAGO reversibly suppressed high-voltage activated calcium currents and slowed their rate of activation, while neither delta- nor kappa-opioid receptor agonists were effective in modifying calcium current in these neurons. The inhibitory effect of DAGO on calcium current was abolished following irreversible blockade of N-type calcium channels by omega-conotoxin GVIA, whereas DAGO-induced inhibitory responses were not affected following blockade of L-type calcium channels by nifedipine. These findings indicate that mu-opioid receptors are negatively coupled to N-type calcium channels on the postsynaptic membrane of basal forebrain neurons. Calcium currents recorded from a significant number of large, mu-opioid sensitive neurons were also suppressed by muscarinic receptor activation, while smaller, mu-opioid sensitive neurons were not sensitive to muscarinic receptor activation. Thus, the present data demonstrate that voltage-activated calcium influx in several subpopulations of basal forebrain neurons can be regulated by mu-opioid receptor activation. These results suggest that mu-opioid regulation of calcium current may be an important functional mechanism in regulating neuronal excitability and synaptic transmission in the basal forebrain.

Sequence of the 305 degrees-307 degrees region of the Bacillus subtilis chromosome.

The nucleotide sequence of the Bacillus subtilis 168 chromosomal segment located between yvhJ (307 degrees) and secA (305 degrees) was determined. This 20.3 kb region encompasses 23 ORFs, 17 of which have been sequenced previously. Comparison of sequences obtained here with the previously obtained ones revealed seven discrepancies. The products of the sequenced genes are involved in the regulation of degradative enzymes, competence, flagellar motility and protein secretion. Putative functions of newly identified genes are based on sequence homologies.

Ionic mechanisms of neuronal excitation by inhibitory GABAA receptors.

Gamma-aminobutyric acid A (GABAA) receptors are the principal mediators of synaptic inhibition, and yet when intensely activated, dendritic GABAA receptors excite rather than inhibit neurons. The membrane depolarization mediated by GABAA receptors is a result of the differential, activity-dependent collapse of the opposing concentration gradients of chloride and bicarbonate, the anions that permeate the GABAA ionophore. Because this depolarization diminishes the voltage-dependent block of the N-methyl-D-aspartate (NMDA) receptor by magnesium, the activity-dependent depolarization mediated by GABA is sufficient to account for frequency modulation of synaptic NMDA receptor activation. Anionic gradient shifts may represent a mechanism whereby the rate and coherence of synaptic activity determine whether dendritic GABAA receptor activation is excitatory or inhibitory.

Sequence analysis of the 308 degrees to 311 degrees segment of the Bacillus subtilis 168 chromosome, a region devoted to cell wall metabolism, containing non-coding grey holes which reveal chromosomal rearrangements.

The 29.71 kb chromosomal region of Bacillus subtilis 168 extending from 308 degrees to 311 degrees contains 18 ORFs. Functions of most of these ORFs were identified and associated with cell wall metabolism. Sequences of two non-coding regions of 0.7 and 2.2 kb flanking the ggaAB operon involved in the synthesis of poly(3-O-beta-D-glucopyranosyl N-acetylgalactosamine 1-phosphate), a minor teichoic acid, correspond to five degenerate segments of neighbouring protein-coding regions. We discuss the possibility that such grey holes are indicative of a chromosomal rearrangement which could have arisen from horizontal gene transfer.

Ethanol differentially modulates GABAA receptor-mediated chloride currents in hippocampal, cortical, and septal neurons in rat brain slices.

Previous electrophysiological studies have reported conflicting results concerning the effects of ethanol on gamma-aminobutyric acid-A (GABAA) receptor-mediated responses in the brain. To examine the variables that might explain these inconsistencies, the present study was designed to determine whether ethanol modulation of synaptically evoked GABA responses is brain region dependent, to identify factors that might regulate ethanol sensitivity, and to investigate the mechanism(s) underlying ethanol modulation of GABA responses. Whole-cell voltage clamp methods were used to examine the effects of ethanol on synaptically evoked GABAA inhibitory postsynaptic currents (IPSCs) recorded from neurons in hippocampus, cerebral cortex, and intermediate lateral and medial septum from rat brain slice preparations. Bicuculline-sensitive IPSCs elicited by local stimulation were pharmacologically isolated by pretreatment with the glutamate specific antagonists, DL-(-)-2-amino-5-phosphonovaleric acid (APV) and 6, 7-dinitroquinoxaline-2, 3-dione (DNQX). Superfused ethanol (80 mM) potentiated evoked GABAA IPSCs in cortical neurons and in intermediate lateral and medial septal neurons but not in CA1 hippocampal neurons. However, the mechanism by which ethanol enhanced GABAA IPSC amplitudes differed between brain regions. In cortex, ethanol induced a hyperpolarizing shift in the GABAA IPSC reversal potential (EIPSC) without modifying the underlying GABAA receptor-mediated conductance (GIPSC). In contrast, ethanol enhanced GABAA IPSC amplitudes differed between brain regions. In cortex, ethanol induced a hyperpolarizing shift in the GABAA IPSC reversal potential (EIPSC) without modifying the underlying GABAA receptor-mediated conductance (GIPSC). In contrast, ethanol enhanced GABAA IPSC amplitudes in lateral and medial septal neurons by increasing the GIPSC without modifying the EIPSC. These results suggest that ethanol differentially modulates responses to endogenous GABA released during synaptic activation and that important differences between various brain regions may reflect multiple mechanisms of ethanol action.

Sequencing and analysis of the divergon comprising gtaB, the structural gene of UDP-glucose pyrophosphorylase of Bacillus subtilis 168.

Nucleotide sequencing revealed that gtaB, the structural gene of UDP-glucose pyrophosphorylase (EC 2.7.7.9), is part of a divergon-like genetic entity. The latter consists of two monocistronic operons gtaB and orfX, transcribed from a 245 bp regulatory region, each encoding an acidic protein with a molecular mass of 33.0 and 42.6 kDa, respectively. gtaB is transcribed from a distal PA promoter, and a proximal PB promoter which is negatively controlled by the Sin protein. Sin-mediated transcriptional attenuation and enhancement of PB and PD, respectively, suggest that these promoters control functions which antagonize each other. Transcription of orfX is mediated by a PA promoter. The regulatory region comprises four ATGAAA hexamers, present as two inverse repeats. Protein GtaB exhibits high homology to analogous prokaryotic enzymes, while OrfX shows 55.4% homology with the product of Escherichia coli o389, which is part of a regulatory unit involved in sugar processing. Mutations gtaB515 and gtaBg100, which define different bacteriophage adsorption patterns, were sequenced. They are transitions leading to substitution of amino acids which occupy conserved positions, and are thus likely to be part of an enzyme active site. The nature of the possible receptors for defective bacteriophages PBSY and PBSZ is discussed.

Ethanol enhances synaptically evoked GABAA receptor-mediated responses in cerebral cortical neurons in rat brain slices.

Previous intracellular electrophysiological studies on rat hippocampal brain slices have shown very little effect of acute ethanol application on synaptically evoked GABAA receptor-mediated responses recorded in CA1 pyramidal neurons. The present study was designed to compare the effects of ethanol on pyramidal neurons in the hippocampus and cerebral cortex. Using conventional intracellular microelectrodes (60-80 M omega) to impale cortical neurons in brain slices, 80 mM ethanol application did not affect the membrane input impedance nor evoked EPSPs, but significantly affected the resting membrane potential (usually a 2-5 mV hyperpolarization). When stimulus-evoked GABAA-mediated IPSCs were studied using whole-cell recordings from cortical neurons voltage-clamped at depolarizing potentials, monophasic IPSCs were evoked that were blocked by bicuculline, increased by pentobarbital, and enhanced by ethanol superfusion in a dose dependent manner over the range of 20-160 mM. Hippocampal IPSCs recorded under identical conditions were not enhanced by ethanol. Parallel studies of GABA-stimulated 36Cl- flux measurements in microsacs prepared from hippocampal, cerebral cortical and cerebellar tissue demonstrated that ethanol significantly enhanced (30-50%) 36Cl- flux in microsacs derived from the cerebral cortex and cerebellum, but not in microsacs prepared from the hippocampus. These results demonstrate that there are clear brain region-dependent differences in the way that GABAA receptor function is altered by acute ethanol, and that these differences are apparent not only as an enhancement of responses to exogenous GABA, but also as a facilitation of the responses to endogenous GABA released from inhibitory nerve terminals during synaptic activation.

Sequencing and analysis of the Bacillus subtilis lytRABC divergon: a regulatory unit encompassing the structural genes of the N-acetylmuramoyl-L-alanine amidase and its modifier.

The regulatory unit of Bacillus subtilis strain 168 encompassing the structural genes of the N-acetylmuramoyl-L-alanine amidase and of its modifier has been sequenced, and found to be a divergon consisting of divergently transcribed operons lytABC and lytR. Proteins LytA, LytB and LytC are endowed with export signal peptides. Mature LytA is a 9.4 kDa, highly acidic polypeptide whose deduced amino acid sequence points to a lipoprotein. LytB and LytC, the modifier and the amidase, are highly basic. After cleavage of the signal sequence their molecular masses are 74.1 and 49.9 kDa, respectively. These two proteins share considerable homology in their N-terminal moieties and have three GSNRY consensus motifs, characteristic of nearly all amidases. The C-terminal moiety of LytB exhibits homology to the product of spoIID. LytR is a 35 kDa protein which acts as an attenuator of the expression of both lytABC and lytR operons. Transcription of the lytABC operon proceeds from two promoters: PD, identified as P28-7 (Gilman et al., 1984), and an upstream PA. The former only is subject to LytR attenuation. Translational initiation of lytB and lytC is directed by UUG start codons, suggesting that lytA, B and C undergo coupled translation. Transcription of lytR is initiated at two start sites, one of which corresponds to a highly intense PA promoter whereas the other does not seem to share much homology with any of the known promoter consensus sequences. Both promoters are attenuated by LytR. It is confirmed that the synthesis of the amidase is controlled at least in part by SigD, i.e. that it belongs to the fla regulon and that its activity, or part of it, is co-regulated with flagellar motility. The role of the mutations conferring the Sin, Fla and Ifm phenotypes in the expression of the lytABC operon is discussed.

Intergenerational transfers: a question of perspective.

Informal intergenerational transfers have traditionally been examined from the perspective of the older generation; more recent studies have proceeded from the perspective of adult children. Drawing upon principles of formal demography, we establish the mathematical relationship between the two generations' perspectives. We then consider the importance of generational perspective with regard to prevalence estimates of intrafamily transfers. Transfers examined include coresidence, household and financial assistance, and personal caregiving. Results have implications for projection of future trends in intrafamily transfers and for data collection.

Family, households, and care arrangements of frail older women: a structural analysis.

Previous research has examined determinants of the living arrangements and the informal-care arrangements of older women; research on care arrangements has often taken living arrangements as given. Here we consider each separately, then go on to analyze the simultaneous determinants of living and care arrangements. Factors influencing these outcomes can be categorized as indicators of opportunities, resources, needs, or preferences. Of particular interest is the extent to which kin availability--specifically, the existence of living children--constrains opportunities, the role of financial resources, and the consequences of needs as revealed by levels of physical and mental disability. Our analysis consists of multinomial-logit models estimated with data from the 1982 National Long-Term Care Survey. The results indicate the importance of kin availability, with striking differences in the living and care arrangements between childless and other older women. Among those with children, there are less striking but consistent differences according to the number and sex composition of living children. Finally, variables representing needs for care are generally the strongest predictors of all the outcomes analyzed.

America's elderly.

The older population in the US has grown twice as fast as the rest of the population in the last 20 years. This growth is expected to accelerate early in the next century as the large baby boom cohorts move through middle age and become elderly. Today, about 1 in 8 Americans is 65 years of age or older. By 2030, 1 out of every 4 persons will be in older person. Substantial improvements in life expectancy at all ages, particularly at extreme old age, mean that not only will there be a greater proportion of elderly in the population, but the more will be the "oldest-old," over 85. By 2050, they will be more than 1/4 of the population. As people live longer, many are active and healthy well past retirement. However, many individuals living into their 80s have to cope with chronic disabilities affecting their capacity to perform day-to-day activities. Modern medicine has made great inroads against mortality from such illnesses as heart disease and stroke, but has not eliminated all the effects of these diseases. As the population ages, the issues of health care funding and availability, particularly long-term care, increase in importance. Contrary to widespread belief, the elderly are not abandoned by their families to nursing home care. The vast majority--95%--live in the community. Those needing assistance generally receive help from family and friends. This has created a tremendous demand for federal subsidies to support community-based long-term care services. 1/4 of the federal budget is now spent on the elderly--$270 billion in 1986. Medicaid and Medicare are among the government's success stories, but these programs are threatened by their very success. Economists estimate that government expenditures are 3 times greater for the elderly than for children, raising the issue of "intergenerational equity"--how to balance the amount of care society provides to those who have already contributed with what is provided to those who will contribute in the future. The view that the young and old simply compete for fixed resources is misleading. It ignores the interdependence among generations, and the burdens and benefits of intergenerational transfers at all stages of the life course.