Biomedical subjects

David W Britt

Publications and source records attributed to David W Britt.

At least 19 recordsLinked to original sources

PubMed2007

Information-sharing among couples considering multifetal pregnancy reduction.

OBJECTIVE: To determine the information-sharing strategies of couples considering fetal reduction, and the impact of these strategies on the chances of encountering hostility in their social networks. DESIGN: Cross-sectional design of semistructured qualitative interviews, coded with respect to sharing strategies and level of personally directed hostility encountered. SETTING: Multiple Pregnancy Management Program, Comprehensive Genetics, New York, New York. PATIENT(S) AND INTERVENTION(S): Fifty women and their partners who were making a first visit to our maternal-fetal management facility, in order to consider the possibility of multifetal reduction as a pregnancy-management strategy. MAIN OUTCOME MEASURE(S): Development of information-sharing strategies, and the chances of encountering personally directed hostility regarding multifetal reduction associated with more and less selective strategies. RESULT(S): Four information-sharing strategies emerged from the analysis. Two of these strategies were relatively open (extended network, and both parents). Two other strategies were relatively selective (qualified family and friends, and defended relationship). The selective strategies were significantly less likely to encounter to encounter personally directed hostility (odds ratio, 3.88; 95% confidence intervals, 0.87-17.30). CONCLUSION(S): Selective sharing of information for couples considering multifetal prgnancy reduction is a potentially useful strategy for moderating potentially stressful relationships in their social networks. Clinics should find a way of integrating the discussion of selective sharing into their clinic's cultural repertoire of patient-support services.

Communication↗

PubMed2007

Humic acid effect on pyrene degradation: finding an optimal range for pyrene solubility and mineralization enhancement.

The addition of humic acid (HA) to polycyclic aromatic hydrocarbon (PAH) contaminated systems has been shown to enhance, inhibit, or have no effect on the biodegradation of these PAHs. In this study, the surfactant effects of Elliott soil HA (ESHA) at two pH values were tested. At pH 7.0, ESHA did not behave as a surfactant. At pH 11.8, ESHA acted as a surfactant, as displayed by a decrease in surface tension with increasing concentrations of ESHA. The effect of ESHA on pyrene solubility was tested by adding 0 to 800 microg ESHA/g soil to soil-slurries. Enhancement of pyrene apparent solubility demonstrated a dose- and time-related effect. Broader doses from 0 to 10,080 microg ESHA/g soil and three higher doses from 3,360 to 10,080 microg ESHA/g soil were tested for their effects on pyrene mineralization by indigenous soil microorganisms and a novel PAH-degrading Mycobacterium sp. KMS in soil microcosms, respectively. ESHA amendments between 20 and 200 microg ESHA/g soil were found to consistently increase pyrene mineralization by indigenous microorganisms, while the 10,080 microg ESHA/g soil produced inhibition and all other doses presented no effects. Pyrene degradation by M. KMS was significantly inhibited by the addition of the highest dose of ESHA.

Biodegradation, Environmental↗

PubMed2006

Formation of protein molecular imprints within Langmuir monolayers: a quartz crystal microbalance study.

Protein imprinting leading to enhanced rebinding of ferritin to ternary lipid monolayers is demonstrated using a quartz crystal microbalance. Monolayers consisting of cationic dioctadecyldimethylammonium bromide, non-ionic methyl stearate, and poly(ethylene glycol) bearing phospholipids were imprinted with ferritin at the air/water interface of a Langmuir-Blodgett trough and transferred hydrated to hydrophobic substrates for study. This immobilization was shown by fluorescence correlation spectroscopy to significantly hinder any further diffusion of lipids, while rebinding studies demonstrated up to a six-fold increase in ferritin adsorption to imprinted versus control monolayers. A diminished rebinding of ferritin to its imprint was observed through pH reduction to below the protein isoelectric point, demonstrating the electrostatic nature of the interaction. Rebinding to films where imprint pockets remained occupied by the template protein was also minimal. Studies with a smaller acidic protein revealed the importance of the steric influence of poly(ethylene glycol) in forming the protein binding pockets, as albumin-imprinted monolayers showed low binding of ferritin, while ferritin-imprinted monolayers readily accommodated albumin. The controllable structure-function relationship and limitations of this system are discussed with respect to the application of protein imprinting in sensor development as well as fundamental studies of proteins at dynamic interfaces.

Adsorption↗

PubMed2006

Sum-frequency spectroscopy analysis of two-component langmuir monolayers and the associated interfacial water structure.

Sum-frequency spectroscopy (SFS) in the CH and OH stretching regions was employed to obtain structural information about Langmuir monolayers on the H(2)O subphase of the model lipid dioctadecyldimethylammonium bromide (DOMA) and of the neutral surfactant methyl stearate (SME) and their mixtures and about the interfacial water structure underneath the films. These results were compared with the sum-frequency spectra of the interface between Langmuir monolayers of stearic acid and stearic acid-DOMA monolayers and water to prove that the uncompensated headgroup charge of DOMA at the interface is the reason for structuring of interfacial water close to the studied monomolecular films. Sum-frequency spectra on D(2)O subphase were also studied to account for the interference between the CH and OH spectral signatures because of the coherent nature of the SFS signals. Interfacial water structure proved to be a determining factor in the behavior of the mixed lipid monolayers. A mixing induced amplification in the surface potential DeltaV observed in our previous work was explained with total increase of the dipole moment for the mixed films, bigger than the arithmetic average for DOMA and SME monolayers alone. The increase is due to the better packing of the molecules in the mixed films and to the decrease in the interfacial water dipole moment arising from a more disordered water structure underneath the mixed monolayers.

Membranes, Artificial↗

PubMed2006

Absorbing and transferring risk: assessing the impact of a statewide high-risk-pregnancy telemedical program on VLBW maternal transports.

BACKGROUND: Prior research has shown that resources have an impact on birth outcomes. In this paper we ask how combinations of telemedical and hospital-level resources impact transports of mothers expecting very low birth weight (VLBW) babies in Arkansas. METHODS: Using de-identified birth certificate data from the Arkansas Department of Health, data were gathered on transports of women carrying VLBW babies for two six-month periods: a period just before the start of ANGELS (12/02-05/03), a telemedical outreach program for high-risk pregnancies, and a period after the program had been running for six months (12/03-05/04). For each maternal transport, the following information was recorded: maternal race-ethnicity, maternal age, and the birth weight of the infant. Logistic regression was used to assess the relationship between the predictors (telemedicine, hospital level, maternal characteristics) and the probability of a transport. RESULTS: Having a telemedical site available increases the probability of a mother carrying a VLBW baby being transported to a level III facility either before or during birth. Having at least a level II nursery also increases the chance of a maternal transport. Where both level II nurseries and telemedical access are available, the odds of VLBW maternal transports are only modestly increased in comparison to the case where neither is present. At the individual level, Hispanic mothers were less likely to be transported than other mothers, and teenaged mothers were more likely to be transported than those 18 and over. A mother's being Black or being over 35 did not have an impact on the odds of being transported to a level III facility. CONCLUSION: Combinations of resources have an impact on physician decisions regarding VLBW transports and are interpretable in terms of the capacity to diagnose and absorb risk. We suggest a collegial review of transport patterns and birth outcomes from areas with different levels of resources as a vehicle for moving the entire system of care forward over time. With such an evidence-based review in place, the collegial relations among level III specialists and obstetricians from around the state can, over time, develop workable protocols for when and how level III facilities should be involved.

Journal Article↗

PubMed2006

Matching risk and resources in high-risk pregnancies.

OBJECTIVE: To evaluate the joint impact of pregnancy risk and the timing of referral of high-risk pregnancies from obstetricians to maternal fetal medicine (MFM) sub-specialists on gestational age (GA) at delivery. METHODS: For the period 1992-2002, 2567 consecutive deliveries from pregnancies of at least 23 weeks gestational age (GA) from a community-level sub-specialty perinatal center were studied. A multiple regression model was developed specifying the impact of various risk factors and referral timing. RESULTS: Prior pregnancy risk was inversely related to GA at birth. Referral timing, operationalized as a continuous variable, did not have a significant additive impact on GA at birth, but several dummy-variable interaction effects combining risk factors and referral before 20 weeks as a dichotomy were significant. CONCLUSION: There are identifiable risks that occur either before the pregnancy or early into it that should lead to early referral to a sub-specialist because of their impact on GA at birth. Early referral is an important tactic in a larger preterm prevention strategy, but it needs to be embedded in a broader maternal-fetal health initiative in which both generalists and sub-specialists play important roles.

Adult↗

PubMed2006

A two-period assessment of changes in specialist contact in a high-risk pregnancy telemedical program.

The purpose was to examine the organizational impact of a state-wide high-risk pregnancy telemedical system, Antenatal and Neonatal Guidelines, Education and Learning System (ANGELS), after the first year of its roll out. The focus is on several aspects of system organization, including the volume and diversity of patient-based telemedical consultations and weekly telemedical case discussions, telephone consultations, and changes in the pattern of birth-related patient transports. Individual data on patient transports and associated hospital days, provider-specialist telephone calls, and telemedical consultations were collected for two time periods: December 2002-May 2003 (prior to initiation of ANGELS), and December 2003-May 2004 (postinitiation of ANGELS). Different statistical tests were constructed to compare the two periods as appropriate. Significant increases were observed in the volume and geographic diversity of telemedical consultations and the volume of telephone consultations. There was a moderate, but nonsignificant decrease in the number of maternal transports to University of Arkansas School of Medical Sciences (UAMS), and the average length of stay decreased. The type of specialist-provider and specialist-patient contact has changed as the ANGELS high-risk pregnancy telemedical system has evolved over the first year. We conclude that the rollout of the ANGELS program is changing the shape of high-risk patient care in Arkansas, and we attribute that to an evolving collegial network between specialists and generalists.

Female↗

PubMed2006

Equity in the development of telemedicine sites in an Arkansas high-risk pregnancy programme.

We investigated where telemedicine sites were placed in a telemedicine network to assist high-risk pregnancies in Arkansas. There were 14 telemedicine sites in 75 counties, excluding the central site in Pulaski county. Logistic regression was used to examine site placement. Five potential predictors of site placement were examined: (1) the logarithm of the number of births in the county (LOGBIRTHS); (2) an indicator of whether a county had an abnormal rate of low birthweight babies (HIGHLBW); (3) the proportion of the county population below the government's poverty level; (4) the ratio of black to white births; (5) an indicator of whether the county bordered the telemedicine hub site county. The results suggested that telemedicine sites were placed where there were more births (LOGBIRTHS, P = 0.001) and more low birthweight babies (HIGHLBW, P = 0.004). After controlling for these variables, the county poverty level did not reduce the likelihood of site placement. Thus telemedicine sites had been established in those areas where the need was great both in terms of immediate risk (rate of low birthweight babies) and in terms of the continuing pressure of large numbers of births. This is significant in view of the concentration of poor minorities in certain areas, which historically have not been matched by past distribution of resources.

Arkansas↗

PubMed2006

A qualitative comparative analysis of the conditions affecting early maternal transfer patterns.

In Arkansas, almost all of the high-risk-pregnancy resources are concentrated in a single place, at the University of Arkansas for Medical Sciences (UAMS). During the 6-month period before a telemedicine programme started, there were five operational telemedicine sites in the state, and during the subsequent 12-month period, there were 13 telemedicine sites in operation. Data were gathered on birth-related transfers during the two periods. Qualitative comparative analysis (QCA) was used to assess the effect of different combinations of telemedical and hospital-level resources on the timing of maternal transfers. Early (pre-33-week gestational age) maternal transfers occurred in period 1 (before the telemedicine programme started), only from areas with level-2 hospital resources and no telemedicine access; early transfers also occurred in period 2 from areas with level-2 hospital resources and either telemedicine access or no telemedicine access. We conclude that combinations of resources affect physician decisions regarding transfer and that QCA is a useful tool for examining the growth and development of telemedicine systems.

Arkansas↗

PubMed2005

Update on selective reduction.

Over the past 25 years fetal reduction has been utilized to reduce the risks of higher-order multiple pregnancies that have resulted from overly successful infertility therapies. The demographics of multiple pregnancy patients have evolved over the past decade, with increasing proportions coming from IVF as opposed to ovulation induction, being older and a higher proportion with donor eggs. Genetic diagnosis prior to reduction is becoming more common and is very safe in experienced hands. For all starting numbers, including twins, reduction to a lower number of fetuses reduces fetal losses, prematurity, and infant mortality and morbidity.

Female↗

PubMed2005

Fetal reduction.

Fetal Reduction has been employed over the past two decades as a mechanism to reduce the morbidity and mortality of multiple pregnancies. Utilization of the procedure has increased dramatically as IVF has become commonplace but the average starting number has decreased with the transfer of fewer embryos. Success rates from fetal reduction have improved as a function of increasing experience, better ultrasound, and lower starting numbers. Genetic diagnosis prior to reduction can improve the overall outcomes. Reduction of triplets or more clearly improves outcomes, and reduction of twins to a singleton is now a reasonable consideration.

Female↗

PubMed2005

Principles of screening.

Screening and diagnostic testing are sequentially-oriented procedures for progressively analyzing risk. Screening is broadly based and aimed at identifying those at high risk of a disease or condition. Diagnostic testing is designed to more definitively answer the question of whether or not a person has a disease or condition. Understanding the differences among four key measures of evaluation for tests (sensitivity, specificity, positive predictive value and negative predictive value) are necessary for proper utilization of screening tests.

Acquired Immunodeficiency Syndrome↗

PubMed2005

Re-evaluating the role of the MFM specialist: lead, follow, or get out of the way.

OBJECTIVE: To assess the effect of sub-specialty prenatal care provided to high-risk obstetrical patients in a community perinatal center as a function of whether consultation and referral to a Maternal-Fetal Medicine (MFM) sub-specialist was at the discretion of the generalist, required by the insurance carrier, or by patient choice. METHODS: Demographics, management, and perinatal outcomes for high-risk patients managed exclusively by MFM were compared with those managed by generalists who were later referred to MFM after problems arose. RESULTS: Despite similar demographics, high-risk patients managed exclusively by a single MFM had less prematurity, lower cesarean section rates, fewer low 5-minute Apgar scores (1.3% vs. 5.5%, p < 0.001), and lower perinatal mortality rates (8.0/1000 vs. 47.6/1000, p < 0.001) than those referred at a later date. CONCLUSIONS: In this setting, earlier MFM care resulted in better outcomes. These data suggest that the 'gatekeeper' model of generalist to MFM might be better the other way around.

Adult↗

PubMed2004

Do reduced multiples do better?

Dramatic successes in infertility care have allowed millions of previously fertile women to have their own children. However, an epidemic of multiple pregnancies has resulted, with catastrophic increases in morbidity and mortality, and in the economic costs to society. Multifetal pregnancy reduction (MFPR) has been used to decrease fetal number in the late first trimester and has dramatically improved outcomes. Recent data suggest that pregnancies starting with three or four, and in some cases five fetuses, which are reduced to twins, do as well as starting with twins. Patients with triplets do better reduced to twins. Reduction to a singleton is becoming more common, particularly for women over 40. Combining MFPR with chorionic villus sampling in patients over 30 years of age has enabled couples to maximize the health of the resultant children.

Abortion, Spontaneous↗

PubMed2004

Fetal reduction from twins to a singleton: a reasonable consideration?

OBJECTIVE: In the past, our group took the position that we would not provide multifetal pregnancy reduction to a singleton regardless of starting number except for serious maternal medical indications or as a selective termination for diagnosed fetal anomalies. With evidence of increased safety and more women (many aged 40 years or more) asking for counseling about reduction to a singleton, we reviewed our prior reasoning. METHODS: We compared outcomes of 52 first-trimester twin-to-singleton for multifetal pregnancy reduction cases performed by a single operator to twin and singleton data from recent national register studies. RESULTS: Twin-to-singleton reductions represent less than 3% of all cases. Forty of 52 patients were aged 35 years or more, 19 were aged more than 40 years, and 2 were aged more than 50 years (age range 32-54 years). Since 1999, 23 of 28 had chorionic villus sampling before multifetal pregnancy reduction. Fifty-one of 52 reached viability with mean gestational age at delivery of 37.2 weeks. One of 52 patients miscarried (1.9%). Compared with multiple sources of data for twins, the loss rate is lower in twins reduced to a singleton. CONCLUSION: Until recently, multifetal pregnancy reductions to a singleton were rare. Physicians were concerned about the unknown risks of multifetal pregnancy reduction in this situation. They also had moral doubts about the justification to go "below twins." However, physicians know that spontaneous twin pregnancy losses average 8-10%. Also, with experience, multifetal pregnancy reduction has become very safe in our hands. Our data suggest that the likelihood of taking home a baby is higher after reduction than remaining with twins. We propose that twin-to-singleton reductions might be considered with appropriate constraints and safeguards.

Abortion, Spontaneous↗

PubMed2002

The genomic revolution and the obstetrician/gynaecologist: from societal trends to patient sessions.

A major aspect of reaping the benefits of the genome revolution in women's health relates to questions of how we are going to handle this scientific manna of information and potential treatment options while minimizing social exclusion along the lines of race, class and gender. Four society-level scenarios or patterns of diffusion of genomic access are discussed, each with its own set of assumptions and outcomes in terms of equity. Like it or not, the front-line obstetrician/gynaecologist will play a critical role in whether such new information helps either to reduce or to exacerbate discrepancies in health-care status along the lines of race and socio-economic status. Patients must not be denied access to knowledge and information within the genetic counselling session, or to the opportunity to make an informed autonomous decision because of the use of unfamiliar language and conventions of conversation that support power differentials and discourage rapport and empathy. Aspects of communication that are critical to the outcome of the genetic counselling session, such as the level of directness of counselling, physician interruptions of the patient and the power implications of the rhetorical question, are explored. In addition, the special challenges to counsellor neutrality and patient autonomy offered by the longitudinal primary obstetrician/gynaecologist relationship are discussed. Strategies encouraging more effective collaboration and communication between generalist and patient in the counselling session are offered.

Communication↗

PubMedDate not supplied

Outreach: targeting high-risk women through community partnerships.

The need for community-based preventive intervention is driven by the ineffectiveness and the costliness of traditional approaches. We argue that community outreach efforts should be characterized by three components: 1) careful mapping of high-risk areas, 2) developing partnerships with trusted community institutions within areas of high risk, and 3) developing a portfolio of institutional partners that maximize the penetration of high-risk populations. The analysis of these high-risk contexts redirects the focus from individuals to institutional structures. Gaining a greater understanding of how impoverished women relate to formal institutions is critical to the primary goal of reducing unnecessary deaths.

Community Health Planning↗

PubMedDate not supplied

Protein insertion and patterning of PEG bearing langmuir monolayers.

Protein adsorption to multicomponent lipid monolayers is presented as a means of inducing protein-specific binding pockets or imprints in membranes. Adsorption of the acidic protein ferritin to Langmuir monolayers of cationic dioctadecyldimethylammonium bromide (DOMA), nonionic methyl stearate (SME), and poly(ethylene glycol) (PEG) bearing phospholipids is investigated as a model system. The number, size, and distribution of protein binding pockets (domains of SME and DOMA in a PEG matrix) are defined by controlling the molar ratios, miscibility, and lateral mobility of the lipids. Protein patterning of binary SME:DOMA monolayers is limited by protein-protein interactions that hinder desorption to regenerate the imprint site. The incorporation of PEG bearing phospholipids as a third lipid component provides a successful approach to prevent protein surface aggregation during imprinting. Atomic force microscopy reveals a user-defined distribution of protein molecules where protein-protein interactions on the monolayer are eliminated, thus facilitating protein desorption and regeneration of the protein binding pockets.

Adsorption↗