To determine whether stavudine (2',3'-didehydro-3'-deoxythymidine) is actively transported in vivo across the placenta and to determine the extent of its transfer, stavudine was administered as an intravenous bolus to four near-term macaques (Macaca nemestrina) (5 mg/kg of body weight via the femoral vein) or to their fetuses (10 mg/kg via the carorid artery) at gestational age 134 +/- 5 days, with the administrations about 1 week apart. Antipyrine (a passive diffusion marker) was always coadministered (20 mg/kg) with stavudine. Samples of maternal and fetal plasma and amniotic fluid were collected at frequent intervals up to 240 min after the dose. In a separate experiment, three animals received stavudine for 30 h at a low rate of infusion (22 micrograms/min/kg via the femoral vein) to the dam or at a 10-fold-higher rate of infusion (220 micrograms/min/kg), separated by at least one week, in order to determine if the transplacental transfer of stavudine is saturable. Antipyrine (41.7 micrograms/min/kg) was coinfused with stavudine. Samples of maternal and fetal plasma and amniotic fluid were collected at regular intervals for up to 30 h. The concentrations of stavudine and antipyrine were determined by high-performance liquid chromatography. The transplacental maternal-fetal drug clearances were compared by the paired Student t test. The clearance associated with maternal-fetal transfer of the drug (CLdf) (0.54 +/- 0.08 ml/min/kg) was not significantly different (P > 0.05) from the clearance associated with fetal-maternal transfer of the drug, CLfd (0.66 +/- 0.11 ml/min/kg). Also, CLdf was not significantly different (P > 0.05) from CLfd when normalized with respect to the corresponding transplacental clearance of antipyrine (0.23 +/- 0.04 versus 0.36 +/- 0.25). The ratios of the steady-state plasma stavudine concentration in the fetus to that in the dam were 0.77 +/- 0.06 at the low stavudine infusion rate and 0.81 +/- 0.09 at the high stavudine infusion rate. The obtained data indicate that transfer of stavudine across the placenta is passive and constant over the dose range studied.

Our objective was to determine whether age affects the pharmacokinetics of stavudine (2,3-didehydro-3-deoxythymidine) in the neonatal pig-tailed macaque (Macaca nemestrina). The drug (5 mg/kg of body weight) was administered serially as a single intravenous bolus to the same four macaques at the ages of <1 week, 1 month, and 4 months. Plasma clearance at <1 week of age was significantly lower (P < 0.05) than the corresponding values at 1 month and 4 months. Our data indicate that the pharmacokinetics of stavudine change significantly with age in M. nemestrina.

findings suggest that interventions can aim at assisting caregivers to regain a sense of control over the changing caregiving situation, in order to help caregivers find meaning in their experience and adapt to their caregiving role. CAREGIVING TRANSITIONS AND LIFE SATISFACTION OF INFORMAL CAREGIVERS R. Keller, APOLLON University of Applied Sciences, Bermen, GermanyIn the Western world, about two third of care recipients are in home care. This fact holds also for Germany: 70 percent of care recipients are cared for at home. Most of the caregivers are family members without any professional background in caregiving. To date, little is known about how caring for a close relative influences life satisfaction of caregivers in the long run. This study seeks to fill the gap by focusing on the process of transitions into and out of their caregiver role. Further, I examine how the caregivers' life satisfaction develops after these incisive life events.The analyses are based on the data of the German SocioEconomic Panel, which provides annual information about caregiving situations in German households and life satisfaction since 1997. Using panel data allows to capture intraindividual changes by controlling time constant unobserved heterogeneity. The longitudinal research design also enables to identify effects of adjustment processes in terms of life satisfaction with respect to transitions into and out of caregiving situations.As expected, life satisfaction decreases after transitioning into the caregiving status and-in contrast to the findings of the vast majority of cross-sectional studies-remains stable over the time of caregiving. When analyzing the period that marks the transition out of caregiving, the picture is rather heterogeneous. It seems that women recover more quickly than men from this strenuous event that is often associated with the death of the care recipient. After recovery, life satisfaction increases constantly for both genders. FINANCIAL COSTS OF CAREGIVING OVER THE LIFECOURSE S.L. Porterfield, H. Shen, Social Work & Gerontology, University of Missouri -Saint Louis, St. Louis, MissouriMany research studies have documented the balancing of work and family life among adults who have caregiving responsibilities. This balance is more tenuous when the care recipient has significant disabilities or special needs. While many parents reduce work hours while their children are young, the work force ties of those whose children have disabilities that affect functioning into adulthood remain weak for a longer period of time, moderated by lower health status among these caregivers.In the US, 70% of working-age adults with disabilities live with relatives; 55% with a parent who is age 60 or older. This paper examines the health and pension costs of caregiving, specifically whether women who are or have been caregivers are more or less likely to hold a pension in their own name, whether there is a significant difference in the value of private pension holdings, given age and health status, and whether these dif...

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