Assessing Antibody Strength: Comparison of MFI, C1q, and Titer Information.

The presence of donor-specific HLA antibodies before or after transplantation may have different implications based on the antibody strength. Yet, current approaches do not provide information regarding the true antibody strength as defined by antigen-antibody dissociation rate. To assess currently available methods, we compared between neat mean fluorescence intensity (MFI) values, C1q MFI values, ethylenediaminetetraacetic acid (EDTA)-treated samples, as well as titration studies and peak MFI values of over 7000 Luminex-based single-antigen HLA antibody data points. Our results indicate that neat MFI values do not always accurately depict antibody strength. We further showed that EDTA treatment (6%) does not always remove all inhibitory factors compared with C1q or titration studies. In this study of patients presenting with multiple antibody specificities, a prozone effect was observed in 71% of the cohort (usually not affecting all antibody specificities within a single serum sample, though). Similar to titration studies, the C1q assay was able to address the issue of potential inhibition; however, its limitation is its low sensitivity and inability to detect the presence of weak antibodies. Titration studies are the only method among the approaches used in this study to provide information suggesting antigen-antibody dissociation rates and are, therefore, likely to provide better indication of true antibody strength.

Predicting XAFS scattering path cumulants and XAFS spectra for metals (Cu, Ni, Fe, Ti, Au) using molecular dynamics simulations.

The ability of molecular dynamics (MD) simulations to support the analysis of X-ray absorption fine-structure (XAFS) data for metals is evaluated. The low-order cumulants (ΔR, σ(2), C3) for XAFS scattering paths are calculated for the metals Cu, Ni, Fe, Ti and Au at 300 K using 28 interatomic potentials of the embedded-atom method type. The MD cumulant predictions were evaluated within a cumulant expansion XAFS fitting model, using global (path-independent) scaling factors. Direct simulations of the corresponding XAFS spectra, χ(R), are also performed using MD configurational data in combination with the FEFF ab initio code. The cumulant scaling parameters compensate for differences between the real and effective scattering path distributions, and for any errors that might exist in the MD predictions and in the experimental data. The fitted value of ΔR is susceptible to experimental errors and inadvertent lattice thermal expansion in the simulation crystallites. The unadjusted predictions of σ(2) vary in accuracy, but do not show a consistent bias for any metal except Au, for which all potentials overestimate σ(2). The unadjusted C3 predictions produced by different potentials display only order-of-magnitude consistency. The accuracy of direct simulations of χ(R) for a given metal varies among the different potentials. For each of the metals Cu, Ni, Fe and Ti, one or more of the tested potentials was found to provide a reasonable simulation of χ(R). However, none of the potentials tested for Au was sufficiently accurate for this purpose.

A plastic miniature x-ray emission spectrometer based on the cylindrical von Hamos geometry.

We present a short working distance miniature x-ray emission spectrometer (miniXES) based on the cylindrical von Hamos geometry. We describe the general design principles for the spectrometer and detail a specific implementation that covers Kß and valence level emission from Fe. Large spatial and angular access to the sample region provides compatibility with environmental chambers, microprobe, and pump/probe measurements. The primary spectrometer structure and optic is plastic, printed using a 3-dimensional rapid-prototype machine. The spectrometer is inexpensive to construct and is portable; it can be quickly set up at any focused beamline with a tunable narrow bandwidth monochromator. The sample clearance is over 27 mm, providing compatibility with a variety of environment chambers. An overview is also given of the calibration and data processing procedures, which are implemented by a multiplatform user-friendly software package. Finally, representative measurements are presented. Background levels are below the level of the Kß(2, 5) valence emission, the weakest diagram line in the system, and photometric analysis of count rates finds that the instrument is performing at the theoretical limit.

Total-reflection inelastic X-ray scattering from a 10-nm thick La0.6Sr0.4CoO3 thin film.

To study equilibrium changes in composition, valence, and electronic structure near the surface and into the bulk, we demonstrate the use of a new approach, total-reflection inelastic x-ray scattering, as a sub-keV spectroscopy capable of depth profiling chemical changes in thin films with nanometer resolution. By comparing data acquired under total x-ray reflection and penetrating conditions, we are able to separate the O K-edge spectra from a 10 nm La0.6Sr0.4CoO3 thin film from that of the underlying SrTiO3 substrate. With a smaller wavelength probe than comparable soft x-ray absorption measurements, we also describe the ability to easily access dipole-forbidden final states, using the dramatic evolution of the La N4,5 edge with momentum transfer as an example.

A short working distance multiple crystal x-ray spectrometer.

For x-ray spot sizes of a few tens of microns or smaller, a millimeter-sized flat analyzer crystal placed approximately 1 cm from the sample will exhibit high energy resolution while subtending a collection solid angle comparable to that of a typical spherically bent crystal analyzer (SBCA) at much larger working distances. Based on this observation and a nonfocusing geometry for the analyzer optic, we have constructed and tested a short working distance (SWD) multicrystal x-ray spectrometer. This prototype instrument has a maximum effective collection solid angle of 0.14 sr, comparable to that of 17 SBCA at 1 m working distance. We find good agreement with prior work for measurements of the Mn Kbeta x-ray emission and resonant inelastic x-ray scattering for MnO, and also for measurements of the x-ray absorption near-edge structure for Dy metal using Lalpha(2) partial-fluorescence yield detection. We discuss future applications at third- and fourth-generation light sources. For concentrated samples, the extremely large collection angle of SWD spectrometers will permit collection of high-resolution x-ray emission spectra with a single pulse of the Linac Coherent Light Source. The range of applications of SWD spectrometers and traditional multi-SBCA instruments has some overlap, but also is significantly complementary.

Determination of the local structure of the first and second shells in ordered and disordered Ni-Mn alloys.

The coordination numbers and the interatomic distances for 50, 75 and 80 at.% Ni-Mn alloys in ordered and disordered states are presented. A new method for determining the first and second nearest neighbor coordination numbers in a binary alloy is applied. It is shown that magnetic properties of these alloys depend on short range order in atomic arrangement.

Availability of child care in the United States: a description and analysis of data sources.

Lack of high-quality, affordable, and accessible child care is an often-cited impediment to a manageable balance between work and family. Researchers, however, have been restricted by a scarcity of data on the availability of child care across all U.S. communities. In this paper we describe and evaluate several indicators of child care availability that have been released by the U.S. Census Bureau over the last 15 years. Using community- and individual-level analyses, we find that these data sources are useful for indicating child care availability within communities, even though they were collected for other purposes. Furthermore, our results generally suggest that the data on child care availability are equally valid across communities of different urbanicity and average income levels, although it appears that larger geographic areas more accurately capture the child care market of centers than that of family day care providers. Our analyses indicate that center child care is least available in nonmetropolitan, poor communities, and that family day care is most available in nonmetropolitan, mixed-income communities. We discuss the benefits and limitations of the data sources, and point to directions for future data developments and research.

Boys who join gangs: a prospective study of predictors of first gang entry.

In a representative sample of boys who were in the 7th grade of an urban public school system at the start of a 6-year longitudinal study, more African American boys (23.8%) than non-Hispanic White boys (3.9%) had entered an antisocial gang by age 19. There were too few White gang members to study, but among African American boys, first gang entry was predicted prospectively by both baseline conduct disorder (CD) behaviors and increasing levels of CD behaviors prior to gang entry. This suggests that gang entry may be a further developmental step for some boys who are already on a trajectory of worsening antisocial behavior. Having friends prior to gang entry who engaged in aggressive delinquency increased the risk of gang entry further, but only during early adolescence. Family income and parental supervision also independently predicted gang entry, but the direction of their influences depended on the youth's age.

Research productivity in the areas of child abuse and domestic violence.

Research productivity in the areas of child abuse and domestic violence was reviewed for the years 1990-1996 by examining articles published in Child Abuse and Neglect, the Journal of Family Violence, and the Journal of Interpersonal Violence. To examine productivity across institutions, quantification of productivity was based on ordinal position of authorship as previously used. Productivity across these three journals was also summed based on the 1987 composite productivity index formula of Howard, et al., and the data were compared with a productivity assessment based on a search process in the PsycLIT database. Rank-order correlations between the raw productivity total, the composite measure, and productivity based on first-authored publications in PsycLIT were all significant. The findings suggest that the composite measure represents a good estimate of productivity across the three journals and that publication in these three journals provides a good representation of research in the general areas of child abuse and domestic and interpersonal violence. The findings, along with implications regarding the relative utility of such information for selection of graduate programs that have a strong research focus on child abuse or domestic violence, are discussed.

Aggressive approach in the treatment of acute lead encephalopathy with an extraordinarily high concentration of lead.

OBJECTIVE: To report a case of a 3-year-old child with an extraordinarily massive lead concentration, 26.4 micromol/L (550 microg/dL), following environmental exposure to lead paint in the home. LITERATURE REVIEW: The relevant literature concerning the treatment of lead encephalopathy was reviewed during the treatment of this child and preparation of the manuscript. To our knowledge, the landmark article written by Julian Chisolm in 1968 is the only recent article that reported similarly high levels of lead concentration. This case, however, is the first in which 3 chelating agents were used for the treatment of lead encephalopathy. We also reviewed the literature on the use of whole bowel irrigation in heavy metal intoxications. CONCLUSIONS: In this case, aggressive gut decontamination with whole bowel irrigation and triple chelation therapy with British anti-Lewisite, EDTA, and oral succimer was well tolerated and seemed effective for rapidly deleading the child. The extent to which her lead concentration increased while being treated with oral succimer alone necessitated further chelation with EDTA. Further evaluation is necessary to determine if triple chelation therapy is an appropriate method for severe lead intoxication, and if the use of whole bowel irrigation should be considered in heavy metal intoxication.

Prevalence of myopia between 3 months and 5 1/2 years in preterm infants with and without retinopathy of prematurity. Cryotherapy for Retinopathy of Prematurity Cooperative Group.

PURPOSE: The purpose of the study was to examine spherical equivalent refractive errors, especially myopia, at six ages between 3 months and 5 1/2 years post-term in preterm children with birth weights of less than 1251 g. DESIGN: A cohort study. PARTICIPANTS: There were a total of 827 participants in the multicenter study of cryotherapy for retinopathy of prematurity (ROP). Approximately one third of the eyes did not develop ROP, whereas two thirds developed mild-to-severe ROP. None of the eyes underwent cryotherapy. INTERVENTION: Refractive error was measured at 3 months, 1 year, and 5 1/2 years term due date at the five long-term follow-up centers. In most eyes, refractive error also was measured at 2, 3 1/2, and 4 1/2 years. MAIN OUTCOME MEASURE: Myopia was defined as 0.25 diopter (D) or greater with high myopia as 5 D or greater. RESULTS: The proportion of eyes with myopia in this preterm population was increased compared to published data on full-term children and was related to severity of both acute-phase and cicatricial-phase ROP. The percentage of eyes with myopia varied little across ages, ranging from 21.2% at 1 year to 15.7% at 4 1/2 years. The percentage of eyes with high myopia doubled from 1.8% to 3.9% between 3 months and 1 year and remained stable thereafter. The distribution of refractive errors in eyes with mild acute-phase ROP was similar to that of eyes with no ROP. In contrast, eyes with moderate or severe acute-phase ROP showed an increased prevalence of high myopia. The distribution of refractive errors changed between 3 months and 1 year with little change after 1 year. This pattern of refractive development differs from that of full-term infants. Birth weight, severity of ROP, and degree of myopia at 3 months predicted the presence of myopia and high myopia at 5 1/2 years of age. CONCLUSIONS: The distribution of refractive errors in preterm infants from age 3 months to 5 1/2 years varies with severity of acute-phase ROP and cicatricial disease. Changes in refractive error distribution occur primarily between 3 months and 1 year and involve a decrease in the proportion of eyes with hyperopia and an increase in the proportion with high degrees of myopia.

Personal need for structure and attitudes toward homosexuality.

The need of a sample of U.S. students to cognitively structure reality as measured by the Personal Need for Structure (PNS) Scale was examined as a predictor of attitudes toward homosexuality measured by the Attitudes Toward Lesbians and Gay Men (ATLG) Scale. Significant relationships between the two constructs and strong gender differences on the ATLG were found.

Maternal smoking during pregnancy and the risk of conduct disorder in boys.

BACKGROUND: Previous animal and human studies have indicated that prenatal exposure to nicotine is associated with adverse reproductive outcomes, including altered neural structure and functioning, cognitive deficits, and behavior problems in the offspring. Our study extends previous research on humans by controlling a broad range of correlates of maternal smoking during pregnancy to determine if smoking is associated with behavior problems in the offspring severe enough to qualify for DSM-III-R diagnosis. METHODS: Subjects were 177 clinic-referred boys, ages 7 to 12 years at the time of the first assessment, who underwent longitudinal assessment for 6 years using annual structured diagnostic interviews. Correlates of maternal smoking during pregnancy and previously identified demographic, parental, perinatal, and family risk factors for the disruptive behavior disorders were controlled in logistic regression analyses. RESULTS: Mothers who smoked more than half a pack of cigarettes daily during pregnancy were significantly more likely to have a child with conduct disorder (odds ratio, 4.4; P = .001) than mothers who did not smoke during pregnancy. This association was statistically significant when controlling for socioeconomic status, maternal age, parental antisocial personality, substance abuse during pregnancy, and maladaptive parenting. CONCLUSIONS: Maternal smoking during pregnancy appears to be a robust independent risk factor for conduct disorder in male offspring. Maternal smoking during pregnancy may have direct adverse effects on the developing fetus or be a marker for a heretofore unmeasured characteristic of mothers that is of etiologic significance conduct disorder.

Further observations on the measurement of fatty acid incorporation by erythrocyte ghosts to quantify unbound palmitate concentration in albumin-palmitate mixtures.

Advantage has been taken of the extensive and reversible incorporation of long-chain fatty acids by erythrocyte ghosts to characterize the interaction of tritium-labeled palmitic acid with human serum albumin (pH 7.4, 37 degrees C). A stoichiometric binding constant for 1:1 complex formation (K1) of 4.6 (+/-0.3) x 10(8) M-1 was obtained from experiments in which erythrocyte ghosts were the source of fatty acid. An essentially identical estimate of 4.1 (+/-0.7) x 10(8) M-1 was obtained from a second series of experiments in which the [3H]palmitate was included with the albumin in the aqueous phase. The magnitude of the present K1 estimate, which is three- to fivefold larger than most recently reported values, reflects binding measurements restricted to a very limited range of unbound palmitate concentration (-0.2 nM) to ensure that the ligand is essentially monomeric. This use of erythrocyte ghosts to quantify the palmitate-albumin interaction has reinforced the basic tenets of a published procedure [I. N. Bojesen, and E. Bojesen (1992) J. Lipid Res. 33, 1327-1334], the major virtue of which is its ability to provide a direct measure of the equilibrium concentration of unbound fatty acid in albumin-palmitate mixtures.

Early retinal vessel development and iris vessel dilatation as factors in retinopathy of prematurity. Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) Cooperative Group.

OBJECTIVE: To determine whether the extent of retinal vessel development present on early screening examinations for retinopathy of prematurity has prognostic value? DESIGN: The prospectively collected data from the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity were used to compare the development of acute retinopathy of prematurity and long-term structural and visual outcomes for eyes with differing extents of retinal vessel development. PATIENT: Study patients had eyes with the following vessel development. In zone I eyes, vessels extended from the disc less than twice the distance from the disc to the macula. In zone II eyes, vessels extended beyond zone I but not to the nasal ora serrata. Transitional eyes had vessels partly in zone I and partly in zone II. RESULTS: The chance of developing threshold retinopathy of prematurity was inversely related to the early degree of vessel development: 54% for zone I eyes, 25% for transitional eyes, and 8% for zone II eyes. The presence of prominent iris vessels at 34 to 35 weeks of postmenstrual age was associated with increased risk for all three groups; zone I eyes almost always needed treatment (94%). The chance of having an unfavorable anatomic alteration of the posterior fundus, or poor vision at the ages of 1 year and 3 1/2 years, was also inversely related to the degree of early vessel development. Vessel development was an independently important factor even when birth weight, gestational age, and race were considered. CONCLUSIONS: The degree of early retinal vessel development is a significant predictor of outcome from retinopathy of prematurity. Iris vessel dilatation is an important indication for greater vigilance in following these infants.

Sex differences in initial clearance of palmitate by human hepatocytes.

To determine if the sex differences in clearance of long chain fatty acids by the liver observed in the rat are relevant to humans, the authors isolated hepatocytes from human adult males and females (five per group) and measured the initial (unidirectional) clearance of [3H]-palmitate from buffer containing albumin. The clearance was significantly higher (about twofold) in hepatocytes from females because of a higher permeability of the plasma membrane to the fatty acid. The livers had been perfused with University of Wisconsin (UW) solution and stored for 12-16 h before isolation of the cells. The magnitudes of the clearances in humans were similar to those in the rat when the livers were stored similarly, but lower than in cells isolated from fresh rat liver. When hepatocytes isolated from fresh rat liver were stored in UW solution, clearance of [3H]-palmitate was unaffected. Thus, hepatocytes prepared from intact liver stored for several hours in UW solution do not have as good preservation of function as hepatocytes isolated from fresh liver and then stored in UW solution.

Effects of gender and pregnancy on hepatocellular uptake of palmitic acid: facilitation by albumin.

The human serum albumin (HSA)-dependent unbound clearance (Clu) of [3H]palmitic acid (PA) by hepatocyte suspensions isolated from immature and mature male and female and pregnant female rats was studied. The Clu values obtained experimentally were compared with the predictions of a noncompartmental diffusion-reaction (Bass-Pond) theory for the cellular uptake of protein-bound ligands. In all groups, as the concentration of HSA (Ca) was increased, there was a striking increase in Clu. These enhancement factors were predicted by the theory. Adult females had higher Clu values at high Ca values than males or immature females. Furthermore, at high Ca values, Clu in pregnant animals was twice as high as in the nonpregnant animals and four times as high as in the aged-matched males. The absolute values of Clu obtained experimentally in both pregnant and nonpregnant females exceeded the maximal predictions of the theory, using reasonable values of all of the parameters. Thus, according to current data on the physicochemical characteristics of the uptake system, the study demonstrates that some specialized process exists to facilitate hepatocellular uptake of fatty acid from albumin, and that it is potentiated by the female sex hormones.

Capillary hemangioma (infantile periocular hemangioma).

Capillary hemangiomas are the most common orbital tumors in children. They typically arise early in life, grow rapidly during a proliferative phase and then slowly regress in an involutional phase. The tumors may present as small isolated lesions of minimal clinical significance or as large disfiguring masses that can cause visual impairment and systemic symptomatology. Capillary hemangiomas are managed effectively by establishing a secure diagnosis, outlining the extent of the tumor, and understanding the natural history of the lesion, as well as its response to therapy. The ophthalmic and systemic manifestations of capillary hemangiomas are discussed in detail, as are the histopathology, radiologic findings, differential diagnosis, and therapeutic alternatives.

The development of the MMPI-A Immaturity Scale: findings for normal and clinical samples.

The Immaturity (IMM) Scale was developed as a supplementary scale for the Minnesota Multiphasic Personality Inventory-Adolescent (MMPI-A). This study describes the development of the IMM Scale and presents some concurrent validity data derived from the MMPI-A normative sample of 1,620 adolescents and a clinical sample of 122 adolescent inpatients. The IMM Scale was examined in relation to Biographical and Life Events data to identify external correlates for the MMPI-A normative sample. In the clinical sample, external correlates were derived from diagnostic and rating form data provided by the adolescents' treatment staff and by their parents. Current findings were discussed in terms of the relationship of correlate patterns to descriptions of the preconformist and conformist stages of Loevinger's (1976) concept of ego development, and future research directions were suggested.