Excess fibrinogen adsorption to monolayers of mixed lipids.

Adsorption of fibrinogen to the monolayers of mixed lipids, dipalmitoyl phosphatidyl choline (DPPC) and eicosylamine (EA) was measured at a surface pressure of 20 mN/m by an in situ surface plasmon resonance technique. Pressure-area isotherms of DPPC+EA mixtures on water and buffer subphases indicated good lipid miscibility and some contraction of the monolayers at intermediate and higher surface pressures. Surface electric potential of the DPPC+EA monolayers showed excess values for intermediate DPPC:EA ratios. Fibrinogen adsorption and its adsorption rates from a dilute solution (0.03 mg/ml) were proportional to the fraction of EA in the monolayer indicating that protein binding was primarily driven by electrostatic interactions between positive EA charges in the monolayer and a net negative protein charge. At a higher protein concentration (0.06 mg/ml) both the fibrinogen adsorbed amount and its maximum adsorption rate showed excess values relative to the pure EA for 1:1, 2:1 and 3:1 DPPC+EA monolayers. This excess adsorption could be explained, in part, by the contraction of the monolayers with intermediate DPPC:EA ratios which resulted in an excess surface electric potential.

Anxiety among women who have undergone fertility therapy and who are considering multifetal pregnancy reduction: trends and implications.

OBJECTIVE: Our primary objective was to evaluate the assumption that women carrying multiple fetuses and who have decided upon multifetal pregnancy reduction (MFPR) have a constant high level of anxiety. METHODS: A total of 66 multigestation women considering MFPR were asked to consider how anxious they were when they first started fertility therapy. Using that level of anxiety as a reference point, and using their self-assessments as a vehicle for probing the meaning they attached to their emotional state through time, they then assessed their anxiety level at different points in their pregnancy. RESULTS: Self-reported anxiety across time displayed considerable variation: there was a large drop in anxiety with pregnancy diagnosis. The women's anxiety rose to very high levels with the diagnosis of carrying multiples. Anxiety moderated again on average with consultation, rose sharply during the course of the procedure, and finally dropped to lower levels on average after the procedure was over. CONCLUSIONS: We conclude that women with multigestation experience considerable fluctuations in their level of anxiety from the time that they first start fertility therapy until they learn that they are carrying multiple embryos. Their expectations for the future of becoming pregnant seem at last fulfilled (becoming pregnant), become complicated (with multiples), appear salvageable (with consultation), but with a morally complicated resolution (MFPR) that seems at last to have put the pregnancy back on a normal track (post-MFPR). Those working with MFPR patients before, during and after the operation must understand the nature and variability of the anxiety that their patients are confronting, and how they are attempting to construct a safe passage through the moral dilemma associated with the multiple-gestation situation.

Bonding and coping with loss: examining the construction of an intervention for multifetal pregnancy reduction procedures.

Multifetal pregnancy reduction is a medical procedure by which pregnancies usually with three or more embryos are reduced in number early in gestation to improve their medical outcomes. A socially constructed intervention used as part of these procedures at Wayne State University is described. The intervention has as its goals the reduction of anxiety in the woman undergoing such a procedure and the refocusing of attention on the surviving 'twins' or singleton. Case materials from 36 cases are examined in detail to document how the intervention is being accomplished in practice, and how it may break down.

Determinants of parental decisions after the prenatal diagnosis of down syndrome: bringing in context.

This article develops the concept of decision context to refer to the combinations of factors that are important in understanding and predicting termination decisions after a prenatal diagnosis of trisomy 21. Four factors are examined: maternal age, gestational age, prior voluntary abortion, and existing children. The cases were studied at the Wayne State University's Reproductive Genetics Clinic. Qualitative comparative analysis, a technique specifically designed for examining the impact of combinations of factors, is used to isolate influential decision contexts. Odds and odds ratios are used to pinpoint outcome differences among different decision contexts. Four alternative decision contexts are especially conducive to choosing to terminate a pregnancy. Two of these involve women of any age and are formed from combinations of gestational age and existing children (existing children and low gestational age, and no children combined with late gestational age). Older women who have not had an abortion and who discover the trisomy 21 anomaly early are likely to choose termination. Younger women who have had an abortion are also likely to choose termination. Our data suggest there are added layers of complexity to patients' decisions that derive from combinations of conditions. An additional, strong implication is that qualitative comparative analysis may be particularly useful in understanding such complexity.

Human low density lipoprotein and human serum albumin adsorption onto model surfaces studied by total internal reflection fluorescence and scanning force microscopy.

The adsorption of low density lipoprotein (LDL) and human serum albumin (HSA) to model surfaces of different hydrophobicities has been studied using two, surface-sensitive, real-time, in situ techniques: total internal reflection fluorescence (TIRF) and scanning force microscopy (SFM). The model surfaces used were: (1) hydrophilic negatively charged silica (TIRF) and mica (SFM) surfaces, (2) hydrophobic octadecyldimethylsilyl-(ODS)-modified silica (TIRF) and ODS-modified oxidized silicon (SFM) surfaces and (3) amphiphilic ODS-silica gradient surfaces (TIRF). The kinetics of fluorescein isothiocyanate-LDL adsorption onto the ODS-silica gradient surface from FITC-LDL solution and from a solution mixture of LDL and HSA showed that a transport-limited process on the clean silica changed into an adsorption-limited process with increasing surface coverage of ODS chains. SFM analysis of the in situ adsorption of LDL on hydrophilic mica demonstrated a steady increase in surface coverage with time which was somewhat lower than determined by TIRF for FITC-LDL adsorption on silica. The adsorption behavior of a binary mixture of HSA and LDL suggested that lateral interactions between HSA and LDL affect the adsorption process. The diameter of LDL adsorbed on mica and ODS-modified silicon has been determined using SFM to be approximately 55 nm. Tetrameric LDL aggregates were observed on all of the surfaces in addition to some dimers and trimers. Imaging LDL and HSA adsorption on clean oxidized silicon surfaces using "contact mode' SFM techniques was hindered by probe manipulation of the proteins.

A longitudinal analysis of alcohol use, environmental conduciveness and normative structure.

The social environment and normative structure surrounding drinking have a reciprocal relationship in determining adolescent drinking patterns in high school and college.