BEhavioral Health Stratified Treatment (B.E.S.T.) to optimize transition to adulthood for youth with intellectual and/or developmental disabilities.

Youth with intellectual and/or developmental disabilities (IDD) often struggle with depression and anxiety, which adversely impacts transition to adulthood. Integrated behavioral health care coordination, wherein care coordinators and behavioral health specialists collaborate to provide systematic, cost-effective, patient-centered care, is a promising strategy to improve access to behavioral health services and address factors that impact transition to adulthood, including depression/anxiety symptoms. Current care coordination models (e.g., Title V Maternal and Child Health Bureau [MCHB]) do not include behavioral health services. The CHECK (Coordinated HealthCarE for Complex Kids) mental health model, hereby refined and renamed BEhavioral Health Stratified Treatment (B.E.S.T.), is a behavioral health intervention delivery program designed for integration into care coordination programs. This study aims to determine whether an integrated behavioral health care coordination strategy (i.e., MCHB care coordination plus B.E.S.T.) would be more acceptable and lead to better youth health and transition outcomes, relative to standard care coordination (i.e., MCHB care coordination alone). Results would guide future investment in improving outcomes for youth with IDD. This study is a two-arm randomized clinical trial of 780 transition-aged youth with IDD (13-20 years) to evaluate the comparable efficacy of MCHB Care Coordination alone vs. MCHB Care Coordination plus B.E.S.T. on the following outcomes: 1) decreased symptoms and episodes of depression and anxiety over time; 2) improved health behaviors, adaptive functioning and health related quality of life; 3) increased health care transition (HCT) readiness; and 4) improved engagement and satisfaction with care coordination among stakeholders.

PATHway: Intervention optimization of a prevention program for adolescents at-risk for depression in the primary care setting.

With as many as 13% of adolescents diagnosed with depressive disorders each year, prevention of depressive disorders has become a key priority for the National Institute of Mental Health (NIMH). Currently, we have no widely available interventions to prevent these disorders. To address this need, we developed a multi-health system collaboration to develop and evaluate the primary care based technology "behavioral vaccine," Competent Adulthood Transition with Cognitive-Behavioral Humanistic and Interpersonal Therapy (CATCH-IT). The full CATCH-IT program demonstrated evidence of efficacy in prevention of depressive episodes in clinical trials. However, CATCH-IT became larger and more complex across trials, creating issues with adherence and scalability. We will use a multiphase optimization strategy approach to optimize CATCH-IT. The theoretically grounded components of CATCH-IT include: behavioral activation, cognitive-behavioral therapy, interpersonal psychotherapy, and parent program. We will use a 4-factor (2x2x2x2) fully crossed factorial design with N = 16 cells (25 per cell, after allowing 15% dropout) to evaluate the contribution of each component. Eligible at-risk youth will be high school students 13 through 18 years old, with subsyndromal symptoms of depression. The study design will enable us to eliminate non-contributing components while preserving efficacy and to optimize CATCH-IT by strengthening tolerability and scalability by reducing resource use. By reducing resource use, we anticipate satisfaction and acceptability will also increase, preparing the way for an implementation trial.

Patient Involvement in the Design of a Patient-Centered Clinical Trial to Promote Adherence to Supplemental Oxygen Therapy in COPD.

BACKGROUND: Patients are increasingly viewed as key stakeholders who can contribute in meaningful ways to clinical research and are emphasized in research funded by the Patient-Centered Outcomes Research Institute (PCORI). We are not aware of other peer-reviewed publications that report methods and outcomes of patient engagement to refine study design for a PCORI-sponsored clinical effectiveness trial. OBJECTIVE: The aim of this report was to describe the process and outcomes of involving patients in the design of a clinical trial to promote adherence to supplemental oxygen therapy among patients with chronic obstructive pulmonary disease. METHODS: In-person focus groups and individual discussions via telephone and email were used to elicit feedback to refine the intervention and clarify outcomes of highest importance to patients. RESULTS: A total of 25 patients and five caregivers provided feedback. Their feedback has informed decisions regarding the length of intervention sessions (20 min and in some cases longer was acceptable), the importance of including caregivers, and discussion topics (e.g., social discomfort about using oxygen in public, identifying personally relevant reasons to use oxygen, pulmonary rehabilitation). Multiple outcomes were rated as highly important to patients (physical function, fatigue, sleep, anxiety, depression, and ability to participate in social roles and activities), and the outcome that was ranked as most important varied by individual. Therefore, multiple patient-reported outcomes will be used as endpoints for the clinical trial. CONCLUSIONS: Patient involvement led to refinements of the intervention and clinical trial endpoints to better address the expressed needs and concerns of patients and caregivers.

Integrating COPD into Patient-Centered Hospital Readmissions Reduction Programs.

About 1 in 5 patients hospitalized for exacerbations of chronic obstructive pulmonary disease (COPD) in the United States are readmitted within 30 days. The U.S. Centers for Medicare and Medicaid Services has recently expanded its Hospital Readmissions Reduction Program to financially penalize hospitals with higher than expected all-cause 30-day readmission rates following a hospitalization for COPD exacerbation. In October 2013, the COPD Foundation convened a multi-stakeholder National COPD Readmissions Summit to summarize our understanding of how to reduce hospital readmissions in patients hospitalized for COPD exacerbations. Over 225 individuals participated in the Summit, including patients, clinicians, health service researchers, policy makers and representatives of academic health care centers, industry, and payers. Summit participants recommend that programs to reduce hospital readmissions: 1) Include specific recommendations about how to promote COPD self-management skills training for patients and their caregivers; 2) Adequately address co-existing disorders common to COPD in care plans during and after hospitalizations; 3) Include an evaluation of adverse events when implementing strategies to reduce hospital readmissions; and 4) Develop a strategy (e.g., a learning collaboratory) to connect groups who are engaged in developing, testing, and implementing programs to reduce hospital readmissions for COPD and other conditions.

Generation of recombinant antibodies to rat GABAA receptor subunits by affinity selection on synthetic peptides.

The abundance and physiological importance of GABAA receptors in the central nervous system make this neurotransmitter receptor an attractive target for localizing diagnostic and therapeutic biomolecules. GABAA receptors are expressed within the retina and mediate synaptic signaling at multiple stages of the visual process. To generate monoclonal affinity reagents that can specifically recognize GABAA receptor subunits, we screened two bacteriophage M13 libraries, which displayed human scFvs, by affinity selection with synthetic peptides predicted to correspond to extracellular regions of the rat α1 and ß2 GABAA subunits. We isolated three anti-ß2 and one anti-α1 subunit specific scFvs. Fluorescence polarization measurements revealed all four scFvs to have low micromolar affinities with their cognate peptide targets. The scFvs were capable of detecting fully folded GABAA receptors heterologously expressed by Xenopus laevis oocytes, while preserving ligand-gated channel activity. Moreover, A10, the anti-α1 subunit-specific scFv, was capable of detecting native GABAA receptors in the mouse retina, as observed by immunofluorescence staining. In order to improve their apparent affinity via avidity, we dimerized the A10 scFv by fusing it to the Fc portion of the IgG. The resulting scFv-Fc construct had a Kd of ∼26 nM, which corresponds to an approximately 135-fold improvement in binding, and a lower detection limit in dot blots, compared to the monomeric scFv. These results strongly support the use of peptides as targets for generating affinity reagents to membrane proteins and encourage investigation of molecular conjugates that use scFvs as anchoring components to localize reagents of interest at GABAA receptors of retina and other neural tissues, for studies of receptor activation and subunit structure.

Interventions to reduce rehospitalizations after chronic obstructive pulmonary disease exacerbations. A systematic review.

RATIONALE: Approximately 20% of patients hospitalized for COPD exacerbations in the United States will be readmitted within 30 days. The Centers for Medicare and Medicaid Services has recently proposed to revise the Hospital Readmissions Reduction Program to financially penalize hospitals with high all-cause 30-day rehospitalization rates after a hospitalization for COPD exacerbation on or after October 1, 2014. OBJECTIVES: To report the results of a systematic review of randomized clinical trials evaluating interventions to reduce the rehospitalizations after COPD exacerbations. METHODS: Multiple electronic databases were systematically searched to identify relevant studies published between January 1966 and June 2013. Titles, abstracts, and, subsequently, full-text articles were assessed for eligibility. Each study was appraised using predefined criteria. MEASUREMENTS AND MAIN RESULTS: Among 913 titles and abstracts screened, 5 studies (1,393 participants) met eligibility criteria. All studies had a primary outcome of rehospitalization at 6 or 12 months. No study examined 30-day rehospitalization as the primary outcome. Each study tested a different set of interventions. Two studies (one conducted in Canada and one conducted in Spain and Belgium) showed a decrease in all-cause rehospitalization over 12 months in the intervention group versus comparator group (mean number of hospitalizations per patient, 1.0 vs. 1.8; P = 0.01; percent hospitalized, 45 vs. 67%; P = 0.028; respectively). The only study conducted in the United States found a greater than twofold higher risk of mortality in the intervention group (17 vs. 7%, P = 0.003) but no significant difference in rehospitalizations. It was unclear which set of interventions was effective or harmful. CONCLUSIONS: The evidence base is inadequate to recommend specific interventions to reduce rehospitalizations in this population and does not justify penalizing hospitals for high 30-day rehospitalization rates after COPD exacerbations.

Chronic obstructive pulmonary disease readmissions at minority-serving institutions.

About 20% of patients hospitalized for chronic obstructive pulmonary disease (COPD) exacerbations are readmitted within 30 days. High 30-day risk-standardized readmission rates after COPD exacerbations will likely place hospitals at risk for financial penalties from the Centers for Medicare and Medicaid Services starting in fiscal year 2015. Factors contributing to hospital readmissions include healthcare quality, access to care, coordination of care between hospital and ambulatory settings, and factors linked to socioeconomic resources (e.g., social support, stable housing, transportation, and food). These concerns are exacerbated at minority-serving institutions, which provide a disproportionate share of care to patients with low socioeconomic resources. Solutions tailored to the needs of minority-serving institutions are urgently needed. We recommend research that will provide the evidence base for strategies to reduce readmissions at minority-serving institutions. Promising innovative approaches include using a nontraditional healthcare workforce, such as community health workers and peer-coaches, and telemedicine. These strategies have been successfully used in other conditions and need to be studied in patients with COPD.

Quantum dot conjugates of GABA and muscimol: binding to α1ß2γ2 and ρ1 GABA(A) receptors.

GABAA receptors are ligand-gated ion channels that mediate inhibitory synaptic signaling in the CNS. Fluorescent probes with the ability to target these receptors can provide insights into receptor location, distribution and dynamics in live cells, while revealing abnormalities in their distribution and dynamics that could occur in a variety of diseases. We have developed fluorescent probes of GABAA receptors that are composed of a CdSe/ZnS core-shell nanocrystal (quantum dot; qdot) conjugated to pegylated derivatives of the GABA receptor agonists GABA and muscimol (GABA-qdots and muscimol-qdots, respectively). Quantitative fluorescence imaging was used to analyze the binding activity of these conjugates to α1ß2γ2 GABAA and ρ1 GABAA receptors expressed in Xenopus oocytes. The selectivity of these conjugates for α1ß2γ2 GABAA and ρ1 GABAA receptors was determined by their ability to compete with the antagonists bicuculline and methyl-(1,2,3,6-tetrahydropyridin-4-yl)phosphinic acid (TPMPA). Both GABA- and muscimol-qdots exhibited robust binding to both α1ß2γ2 and ρ1 GABAA receptors. At α1ß2γ2 receptors, pretreatment with bicuculline reduced conjugate binding by ≥8-fold on average, an extent far exceeding the reduction produced by TPMPA (~30%). Conversely, at ρ1 receptors, pretreatment with TPMPA inhibited binding by ~10-fold, an extent greatly exceeding the change produced by bicuculline (~50% or less). These results indicate specific binding of muscimol-qdots and GABA-qdots to α1ß2γ2 GABAA and ρ1 GABAA receptors in a manner that preserves the respective pharmacological sensitivities of these receptors to TPMPA and bicuculline, and encourage the use of qdot-conjugated neurotransmitter analogs as labeling agents at GABAA receptors.

Cysteine-terminated B-domain of Staphylococcus aureus protein A as a scaffold for targeting GABA(A) receptors.

This study reports the preparation and characterization of cysteine-terminated B-domain (Bd-cys) of Staphylococcus aureus protein A, in combination with immunoglobulin G (IgG) antibodies directed against the ρ1 and α1 subunits of GABA(A) receptors, for localizing reagents of interest to the target receptor. A cysteine residue was inserted at the C terminus of the cysteine-lacking B-domain (Bd) and used for conjugating maleimide-containing compounds. As determined by enzyme-linked immunosorbent assay (ELISA), binding of a Bd-cys-S-fluorescein conjugate to polyclonal guinea pig anti-GABA(A)-ρ1 and rabbit anti-GABA(A)-α1 IgG was similar to that exhibited by full-length protein A. Surface plasmon resonance analysis of the interaction of Bd-cys-S-PEG3400-biotin conjugate (where PEG is polyethylene glycol) with anti-GABA(A)-ρ1 and anti-GABA(A)-α1 yielded K(D) values of 6.4 ± 1.9 and 0.4 ± 0.1 nM, respectively. Fluorescence anisotropy analysis of the binding of Bd-cys-S-fluorescein to the two antibodies yielded EC50 values of 65 and 18 nM, respectively. As determined with biotin-reactive fluorescent reagents, Bd-cys-S-PEG3400-biotin specifically bound to the plasma membrane of Xenopus laevis oocytes that expressed α1ß2γ2 or homomeric ρ1 GABA(A) receptors and were pretreated with the corresponding anti-GABA(A) IgG. The IgG-binding specificity and high affinity of Bd-cys conjugates illustrate the potential of these conjugates, in combination with a selected IgG, to localize compounds of interest at specific cell surface proteins.

Subunit-specific polyclonal antibody targeting human ρ1 GABA(C) receptor.

The GABA(C) receptor, a postsynaptic membrane receptor expressed prominently in the retina, is a ligand-gated ion channel that consists of a combination of ρ subunits. We report characterization of a novel guinea pig polyclonal antibody, termed GABA(C) Ab N-14, directed against a 14-mer peptide (N-14) of the extracellular domain of the human ρ1 subunit. The antibody exhibits high sensitivity for N-14 by ELISA. In Western blots, GABA(C) Ab N-14 shows reactivity with the ρ1 subunit of preparations obtained from ρ1 GABA(C)-expressing neuroblastoma cells, Xenopus oocytes, and mammalian retina and brain. Flow cytometry reveals a rightward shift in mean fluorescence intensity of GABA(C)-expressing neuroblastoma cells probed with GABA(C) Ab N-14. Immunostaining of neuroblastoma cells and oocytes with GABA(C) Ab N-14 yields fluorescence only with GABA(C)-expressing cells. Antibody binding has no effect on GABA-elicited membrane current responses. Immunostaining of human retinal sections shows preferential staining within the inner plexiform layer. GABA(C) Ab N-14 appears well suited for investigative studies of GABA(C) ρ1 subunit in retina and other neural tissues.

Generation of recombinant guinea pig antibody fragments to the human GABAC receptor.

To generate monoclonal antibodies to the human ρ1 GABA(C) receptor, a ligand-gated chloride ion channel that is activated by the neurotransmitter γ-aminobutyric acid (GABA), we recovered the immunoglobulin variable heavy chain (V(H)) and light chain (V(L)) regions of a guinea pig immunized with a 14-mer peptide segment of the N-terminal extracellular domain of the ρ1 subunit. Oligonucleotide primers were designed and used to amplify the V(H) and V(L) regions of guinea pig RNA by the reverse transcriptase polymerase chain reaction. The amplified and cloned V(H) and V(L) regions were transferred together into a phagemid vector, yielding a library of 5×10(6) members, which displayed chimeric fragments of antigen binding (Fabs) with guinea pig variable and human constant regions fused to protein III of M13 bacteriophage. Through affinity selection of this phage-display library with the biotinylated 14-mer peptide segment of GABA(C), we isolated four different antibody fragments that bound specifically to the immunogenic peptide. Phage particles displaying two of these antibodies, but not negative controls, bound selectively to the surface of neuroblastoma cells expressing the ρ1 GABA(C) receptor. Such antibody fragments will be useful in future studies involving targeting of specific neural tissues that express the GABA(C) receptor.

GABAC receptor binding of quantum-dot conjugates of variable ligand valency.

Highly fluorescent CdSe quantum dots (qdots) can serve as a platform for tethering multiple copies of a receptor-targeted ligand, affording study of how the level of multivalency affects receptor binding. We previously showed that qdots conjugated with long PEG chains terminated by muscimol, a known GABA(C) agonist, exhibit specific binding to the surface membrane of GABA(C) receptor-expressing Xenopus oocytes. The present report addresses the effect of varying the number, i.e., valency, of muscimol- (M-) terminated PEG chains attached to the qdot on binding of the resulting conjugate to GABA(C) receptors. M-PEG-qdots of differing muscimol valency were prepared by conjugating AMP-CdSe/ZnS qdots with muscimol-terminated and methylamine-terminated PEG chains in proportions designed to yield varying percentages of muscimol-terminated chains among the total approximately 150-200 chains bound to the qdot. The investigated valencies represented 0%, approximately 25%, approximately 50%, and 100% loading with muscimol (preparations termed M-PEG-qdot0, M-PEG-qdot25, M-PEG-qdot50, and M-PEG-qdot100, respectively. Binding of a given conjugate to surface membranes of GABA(C) receptor-expressing oocytes was analyzed by quantitative fluorescence microscopy following defined incubation with approximately 30 nM of the conjugate. With 5-20 min incubation, the fluorescence signal resulting from incubation with M-PEG-qdot25 exceeded, by approximately 6-fold, the fluorescence level obtained with M-PEG-qdot preparations that lacked muscimol-terminated chains (M-PEG-qdot0). M-PEG-qdot50 yielded a net signal roughly similar to that of M-PEG-qdot25, and that produced by M-PEG-qdot100 exceeded, by approximately 30-50%, those for M-PEG-qdot25 and M-PEG-qdot50. The time course of changes in oocyte surface membrane fluorescence resulting from the introduction of and removal of M-PEG-qdots in the medium bathing the oocyte indicated only a modest dependence of both binding and wash-out kinetics on muscimol valency. The results demonstrate a dependence of the binding activity of the M-PEG-qdot conjugates on muscimol valency, presumably reflecting higher GABA(C) avidity and/or affinity of the muscimol at high valency, and provide insight on the interactions of membrane receptor proteins with qdot conjugates containing multiple copies of a receptor-targeting ligand.

Structural model of rho1 GABAC receptor based on evolutionary analysis: Testing of predicted protein-protein interactions involved in receptor assembly and function.

The homopentameric rho1 GABA(C) receptor is a ligand-gated ion channel with a binding pocket for gamma-aminobutyric acid (GABA) at the interfaces of N-terminal extracellular domains. We combined evolutionary analysis, structural modeling, and experimental testing to study determinants of GABA(C) receptor assembly and channel gating. We estimated the posterior probability of selection pressure at amino acid residue sites measured as omega-values and built a comparative structural model, which identified several polar residues under strong selection pressure at the subunit interfaces that may form intersubunit hydrogen bonds or salt bridges. At three selected sites (R111, T151, and E55), mutations disrupting intersubunit interactions had strong effects on receptor folding, assembly, and function. We next examined the role of a predicted intersubunit salt bridge for residue pair R158-D204. The mutant R158D, where the positively charged residue is replaced by a negatively charged aspartate, yielded a partially degraded receptor and lacked membrane surface expression. The membrane surface expression was rescued by the double mutant R158D-D204R, where positive and negative charges are switched, although the mutant receptor was inactive. The single mutants R158A, D204R, and D204A exhibited diminished activities and altered kinetic profiles with fast recovery kinetics, suggesting that R158-D204 salt bridge perhaps stabilizes the open state of the GABA(C) receptor. Our results emphasize the functional importance of highly conserved polar residues at the protein-protein interfaces in GABA(C) rho1 receptors and demonstrate how the integration of computational and experimental approaches can aid discovery of functionally important interactions.

Imaging GABAc receptors with ligand-conjugated quantum dots.

We report a methodology for labeling the GABAc receptor on the surface membrane of intact cells. This work builds upon our earlier work with serotonin-conjugated quantum dots and our studies with PEGylated quantum dots to reduce nonspecific binding. In the current approach, a PEGylated derivative of muscimol was synthesized and attached via an amide linkage to quantum dots coated in an amphiphilic polymer derivative of a modified polyacrylamide. These conjugates were used to image GABA(C) receptors heterologously expressed in Xenopus laevis oocytes.

Binding of muscimol-conjugated quantum dots to GABAC receptors.

Functionalization of highly fluorescent CdSe/ZnS core-shell nanocrystals (quantum dots, qdots) is an emerging technology for labeling cell surface proteins. We have synthesized a conjugate consisting of approximately 150-200 muscimols (a GABA receptor agonist) covalently joined to the qdot via a poly(ethylene glycol) (PEG) linker (approximately 78 ethylene glycol units) and investigated the binding of this muscimol-PEG-qdot conjugate to homomeric rho1 GABAC receptors expressed in Xenopus oocytes. GABAC receptors mediate inhibitory synaptic signaling at multiple locations in the central nervous system (CNS). Binding of the conjugate was analyzed quantitatively by determining the fluorescence intensity of the oocyte surface membrane in relation to that of the surrounding incubation medium. Upon 5- to 10-min incubation with muscimol-PEG-qdots (34 nM in qdot concentration), GABAC-expressing oocytes exhibited a fluorescent halo at the surface membrane that significantly exceeded the fluorescence of the incubation medium. This halo was absent following muscimol-PEG-qdot treatment of oocytes lacking GABAC receptors. Incubation of the oocyte with free muscimol (100 microM-5 mM), PEG-muscimol (500 microM), or GABA (100 microM - 5 mM) substantially reduced or eliminated the fluorescence halo produced by muscimol-PEG-qdots, and the removal of GABA or free muscimol led to a recovery of muscimol-PEG-qdot binding. Unconjugated qdots and PEG-qdots that lacked conjugated muscimol neither exhibited significant binding activity nor diminished the subsequent binding of muscimol-PEG-qdots. The results indicate that muscimol joined to qdots via a long-chain PEG linker exhibits specific binding activity at the ligand-binding pocket of expressed GABAC receptors, despite the presence of both the long PEG linker and the sterically bulky qdot.

Culture of cells from maternal circulation, in conditions favoring fetal endothelial cell expansion, does not facilitate the preferential expansion of circulating fetal cells.

OBJECTIVES: To establish optimal culture conditions for fetal endothelial cells, and determine whether these can be used for preferential expansion of fetal cells from maternal blood. METHODS: Human adult microvascular and umbilical vein endothelial cells were cultured in the presence of colony-stimulating factor-1 (CSF-1), placental growth factor (PlGF), and transforming growth factor-beta1 (TGF-beta1). The effect of each cytokine was assessed. We expanded peripheral blood mononuclear cells (PBMCs) from 18 pregnant women using the conditions most favorable to fetal cells; in specimens from women carrying male fetuses (n = 9), cell origin was determined by PCR (SRY locus). RESULTS: The optimal concentrations of CSF-1, PlGF and TGF-beta1 were 10, 100, and 5 ng/ml, respectively. PBMCs from maternal blood expanded in the presence or absence of the cytokines; PCR analysis showed no Y sequences in cultured maternal samples. CONCLUSION: Optimal concentrations of CSF-1, PlGF and TGF-beta1 for preferential expansion of fetal endothelial cells were determined in model cultures. However, when these conditions were applied to maternal blood samples, no fetal cells could be detected based on PCR for SRY in women carrying male fetuses.

Culture of endothelial cells isolated from maternal blood using anti-CD105 and CD133.

OBJECTIVES: We hypothesized that fetal cells in maternal blood that do not respond to hematopoietic culture conditions represent endothelial cells. We investigated whether endothelial progenitor cells of fetal origin may be selected from maternal blood on the basis of their expression of CD133 or CD105 and expanded in culture. METHODS: Peripheral blood mononuclear cells from 16 pregnant women (gestational age: 11 to 24 weeks) were labeled with magnetic beads coupled to anti-CD133 or anti-CD105. Selection of labeled cells was performed using MACS. Resulting CD133+, CD105+, and CD133-/CD105- cell fractions were placed in culture in conditions favoring endothelial cells for 7 days (positive fractions) to 30 days (depleted fractions). Cells from women carrying male fetuses were analyzed by conventional PCR (SRY primers) for detection of male cells. RESULTS: Expansion of cells isolated from all subjects occurred in each of the cell fractions. No PCR products consistent with the presence of male cells were detected in women carrying male fetuses. CONCLUSION: CD133+ and CD105+ cells isolated from maternal blood can be expanded in vitro under endothelial conditions. These cells appear to be of maternal, rather than fetal, origin.

Culture of fetal cells from maternal blood for prenatal diagnosis.

The isolation and analysis of fetal cells from maternal blood would allow non-invasive prenatal genetic screening and diagnosis. Over the past decade, progress has been made towards this goal using various enrichment strategies and analysis by fluorescence in-situ hybridization with chromosome-specific probes and PCR. One method that is currently being explored involves culturing fetal cells. Developing conditions which allow the number of fetal-derived cells to expand in culture and the number of maternally derived cells to be suppressed in culture may lead to a new selection process for obtaining fetal cells. Culturing of fetal cells from maternal blood could make possible conventional metaphase analysis of fetal cells for diagnosis of chromosomal abnormalities.

Endothelial precursor cells in the peripheral blood of pregnant women.

OBJECTIVE: To determine whether primitive endothelial precursor cells are present in the peripheral blood of pregnant compared with nonpregnant subjects and whether these precursor cells are of fetal or maternal origin. METHODS: Peripheral blood mononuclear cells from 13 pregnant women in the second trimester and from ten nonpregnant women and men were cultured for 8-10 weeks under conditions that promoted endothelial cell development. Early outgrowth (1 week culture) and late outgrowth (4-6 weeks) colonies were observed, their endothelial nature was investigated, and fluorescence in situ hybridization was performed to determine the origin of the colonies from pregnant women's specimens. RESULTS: Peripheral blood mononuclear cell cultures from all pregnant women and all nonpregnant controls yielded early-outgrowth endothelial cells. Late-outgrowth endothelial cells were observed in 61.5% (eight of 13) of pregnant subjects, but in none of the ten nonpregnant controls (chi(2) test; P <.01). The adherent cells stained positively for von Willebrand factor and incorporated Dil-Ac-LDL, confirming their endothelial origin. Fluorescence in situ hybridization analysis showed only X chromosome-specific signals and no Y chromosome-specific signals in the cells from the late-outgrowth endothelial cells in all pregnant women carrying either a male (n = 5) or a female (n = 8) fetus. CONCLUSION: Primitive endothelial precursor cells are present in most pregnant women during the second trimester. These cells appear to be of maternal origin.