Stimuli-responsive self-assembled polymer nanoparticles for the oral delivery of antibodies

Currently, commercially available antibody therapies must be delivered via parenteral administration. Oral delivery of antibodies could increase patient compliance and improve quality of life, however there is currently no viable system for delivering antibodies orally. In this work, a self-assembled, pH-responsive nanoparticle delivery system was developed to load and deliver antibodies via the oral route. The nanoparticles were synthesized via nanoprecipitation using the pH-responsive copolymers based on poly(methacrylic acid-co-methyl methacrylate)-block-poly(ethylene glycol). The reversibly hydrophobic nature of this polymer allowed it to function as an antibody delivery system via self-assembly. Characteristics of the polymer, including monomer ratios and molecular weight, as well as parameters of the nanoprecipitation process were optimized using Design of Experiments to achieve nanoparticles with desired size, polydispersity, loading efficiency, and release characteristics. Ultimately, the synthesized and optimized nanoparticles exhibited a hydrodynamic size within a range that avoids premature clearance, a low polydispersity index, and high IgG loading efficiency. In in vitro antibody release studies at physiologically relevant pH values, the nanoparticles exhibit promising release profiles. The nanoparticles presented in this work show potential as oral delivery vehicles for therapeutic antibodies.

Vacancy-controlled ultrastable nanoclusters in nanostructured ferritic alloys

A new class of advanced structural materials, based on the Fe-O-vacancy system, has exceptional resistance to high-temperature creep and excellent tolerance to extremely high-dose radiation. Although these remarkable improvements in properties compared to steels are known to be associated with the Y-Ti-O-enriched nanoclusters, the roles of vacancies in facilitating the nucleation of nanoclusters are a long-standing puzzle, due to the experimental difficulties in characterizing vacancies, particularly in-situ while the nanoclusters are forming. Here we report an experiment study that provides the compelling evidence for the presence of significant concentrations of vacancies in Y-Ti-O-enriched nanoclusters in a nanostructured ferritic alloy using a combination of state-of-the-art atom-probe tomography and in situ small angle neutron scattering. The nucleation of nanoclusters starts from the O-enriched solute clustering with vacancy mediation. The nanoclusters grow with an extremely low growth rate through attraction of vacancies and O:vacancy pairs, leading to the unusual stability of the nanoclusters.

Enhancing glass-forming ability via frustration of nano-clustering in alloys with a high solvent content

The glass-forming ability (GFA) of alloys with a high-solvent content such as soft magnetic Fe-based and Al-based alloys is usually limited due to strong formation of the solvent-based solid solution phase. Herein, we report that the GFA of soft magnetic Fe-based alloys (with >70 at.% Fe to ensure large saturation magnetization) could be dramatically improved by doping with only 0.3 at.% Cu which has a positive enthalpy of mixing with Fe. It was found that an appropriate Cu addition could enhance the liquid phase stability and crystallization resistance by destabilizing the α-Fe nano-clusters due to the necessity to redistribute the Cu atoms. However, excessive Cu doping would stimulate nucleation of the α-Fe nano-clusters due to the repulsive nature between the Fe and Cu atoms, thus deteriorating the GFA. Our findings provide new insights into understanding of glass formation in general.

Detecting density variations and nanovoids

A combination of simulated and experimental data has been used to investigate the size range of nanovoids that can be detected in atom probe tomography data. Simulated atom probe tomography data have revealed that nanovoids as small as 1 nm in diameter can be detected in atom probe tomography data with the use of iso-density surfaces. Iso-density surfaces may be used to quantify the size, morphology and number density of nanovoids and other variations in density in atom probe tomography data. Experimental data from an aluminum-yttrium-iron metallic glass ribbon have revealed the effectiveness of this approach. Combining iso-density surfaces with atom maps also permits the segregation of solute to the nanovoids to be investigated. Field ion microscopy and thin section atom maps have also been used to detect pores and larger voids.

WITHDRAWN: A MVSA approach to mine information from APT data

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Atom probe specimen preparation with a dual beam SEM/FIB miller

Dual beam scanning electron microscope/focused ion beam (SEM/FIB) methods complement electropolishing methods and enable specimens to be made from a wider range of materials. Several methods have been developed to fabricate specimens from different forms of materials, including thin ribbons, mechanically ground sheet and fine powders. In addition, FIB-based methods can be used in conjunction with electropolishing methods to improve the shape, surface finish and taper angle of specimens. Several lift-out (LO) methods have been developed for selecting specific microstructural features or other regions of interest such as phases, interfaces, grain boundaries, subsurface or implanted regions and interdendritic regions. These LO methods make use of an in situ nanomanipulator and platinum deposition to transfer and attach the lifted out volume to a post for final annular milling into a needle-shaped specimen. In order to improve the efficiency and to facilitate the LO procedure, some special specimen mounts that hold both the specimen and the support post at the appropriate working distance have been developed.

Performance of local electrodes in the local electrode atom probe

The use of a local electrode in atom probe tomography has enabled higher rates of data acquisition and increased field of view compared to other variants of three-dimensional atom probes, but specimen fracture can result in damage to the local electrode. Specimens and local electrodes were examined before and after analyses that resulted in specimen failure. Most specimens were found to be melted after failure and as a result, material was found deposited onto the surface of the local electrode. Material transfer from the specimen to the local electrode was verified by energy dispersive spectrometry in a scanning electron microscope. After the fracture of brittle materials, some remnants were found embedded in the local electrode. For either failure mode, it is likely that the primary specimen rupture produced a sharp protrusion on the specimen or local electrode and this triggered an electrical discharge or uncontrolled field emission that melted a portion of the specimen. The lifetime of the local electrode was found to be dependent on the shape and position of the debris from the specimen failure rather than the number of ions collected or the number of specimens characterized. Local electrodes with smaller apertures were found to be more susceptible to failure.

TENOR risk score predicts healthcare in adults with severe or difficult-to-treat asthma

The aim of the present study was to predict which patients with severe or difficult-to-treat asthma are at highest risk for healthcare utilisation can be predicted so as to optimise clinical management. Data were derived from 2,821 adults with asthma enrolled in The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens (TENOR) study. Multiple potential predictors were assessed at baseline using a systematic algorithm employing stepwise logistic regression. Outcomes were asthma-related hospitalisations or emergency department (ED) visits within 6 months following baseline. Overall, 239 subjects (8.5%) reported hospitalisation or ED visits at follow-up. Predictors retained after multivariate analysis were as follows: younger age; female sex; non-white race; body mass index > or =35 kg x m(-2); post-bronchodilator per cent predicted forced vital capacity <70%; history of pneumonia; diabetes; cataracts; intubation for asthma; and three or more steroid bursts in the prior 3 months. A final risk score derived from the logistic regression model ranged from 0-18 and was highly predictive (c-index: 0.78) of hospitalisation or ED visits. This tool was re-tested in a prospective validation using outcomes at 12- to 18-months follow-up among the same cohort (c-index: 0.77). The risk score derived is a clinically useful tool for assessing the likelihood of asthma-related hospitalisation or emergency department visits in adults with severe and difficult-to-treat asthma.

Strategies for fabricating atom probe specimens with a dual beam FIB

A FIB-based lift-out method for preparing atom probe specimens at site specific locations such as coarse precipitates, grain boundaries, interphase interfaces, denuded zones, heat affected zones, implanted, near surface and subsurface regions, shear bands, etc. has been developed. FIB-based methods for the fabrication of atom probe specimens from thin ribbons, sheet stock, and powders have been developed.

Circumferential Adjustment of Ultrasound Probe Position to Determine the Optimal Approach to the Internal Jugular Vein: A Noninvasive Geometric Study in Adults

Circumferential adjustment of the position of a two-dimensional ultrasound (US) probe around the neck has been recommended as a strategy for reducing the potential for unintentional common carotid artery puncture during internal jugular venous (IJV) cannulation. We obtained multiple high-resolution US images bilaterally from the necks of 107 adult subjects and analyzed these to determine the degree to which this strategy permits identification of a pathway from the skin to the IJV that minimizes venoarterial overlap while maximizing venous target (angular) width. The method consistently permitted identification of an approach to the IJV superior to that obtainable with any one of four popular surface anatomy-based ("blind") approaches and was even more powerful if used in concert with a US-guided 1) adjustment of the degree of head rotation, 2) choice between a high and low approach, and 3) choice between the right and left IJV. Use of a high-resolution US imaging device also permitted identification of the precise boundaries of additional cervical anatomic structures (nontarget vessels, lymph nodes, and the thyroid gland) potentially relevant to selection of an optimal approach to the IJV.

Some aspects of atom probe specimen preparation and analysis of thin film materials

Some of the factors in the preparation of atom probe specimens of metallic multilayer thin films have been investigated. A series of Ti/Nb multilayer films were sputtered deposited on n-doped Si [001] substrates with either 5 or 0.05Omega cm resistivity. Each wafer was pre-fabricated into a series of 5 microm x 5 microm x approximately 80 microm island posts by photolithography and reactive ion etching. Once the film was grown on the wafer, a Si post was mounted to either a tungsten or stainless steel fine tip needle that was mechanically crimped to a Cu tube for handling. The specimen was then loaded into a Focus Ion Beam instrument where a sacrificial Pt cap was in situ deposited onto the surface of the film and subsequently annularly ion milled into the appropriate geometry. The Pt cap was found to be an effective method in reducing Ga ion damage and implantation into the film during milling. The multilayers deposited on the high resistivity Si exhibited uncontrolled field evaporation which lead to high mass tails in the mass spectra, a reduction in the mass resolution, high background noise, propensity for "flash-failure", and a variation in the apparent layer thickness as the experiment elapsed in time. The multilayers deposited on lower resistivity Si did not suffer from these artifacts.

Atom probe tomography: a technique for nanoscale characterization

Atom probe tomography is a technique for the nanoscale characterization of microstructural features. Analytical techniques have been developed to estimate the size, composition, and other parameters of features as small as 1 nm from the atom probe tomography data. These methods are outlined and illustrated with examples of yttrium-, titanium-, and oxygen-enriched particles in a mechanically alloyed, oxide-dispersion-strengthened steel.

Do learning style and learning environment affect learning outcome?

This study compared learning outcomes of students with different learning styles, as identified by the Kolb Learning Style Inventory indicators, in a traditional in-class environment with those taking the same course via distance education. The above-average scores were evenly distributed, 47% of the in-class group and 43% of the distance group. For three of the four learning styles, there was no relationship to learning outcome or environment. The Diverger group did show a relationship with above-average scores in the distance group (83%). The findings support that the classroom or distance environment did not influence learning outcome. Learning style did not appear to affect learning outcome in either group, except that the Diverger learning style may have a positive relationship to learning in the distance environment.

Analysis conditions of an industrial Al-Mg-Si alloy by conventional and 3D atom probes

Industrial 6016 Al-Mg-Si(Cu) alloys are presently regarded as attractive candidates for heat treatable sheet materials. Their mechanical properties can be adjusted for a given application by age hardening of the alloys. The resulting microstructural evolution takes place at the nanometer scale, making the atom probe a well suited instrument to study it. Accuracy of atom probe analysis of these aluminium alloys is a key point for the understanding of the fine scale microstructural evolution. It is known to be strongly dependent on the analysis conditions (such as specimen temperature and pulse fraction) which have been widely studied for ID atom probes. The development of the 3D instruments, as well as the increase of the evaporation pulse repetition rate have led to different analysis conditions, in particular evaporation and detection rates. The influence of various experimental parameters on the accuracy of atom probe data, in particular with regard to hydride formation sensitivity, has been reinvestigated. It is shown that hydrogen contamination is strongly dependent on the electric field at the specimen surface, and that high evaporation rates are beneficial. Conversely, detection rate must be limited to smaller than 0.02 atoms/pulse in order to prevent drastic pile-up effect.

Fabrication of specimens of metamorphic magnetite crystals for field ion microscopy and atom probe microanalysis

Field ion specimens have been successfully fabricated from samples of metamorphic magnetite crystals (Fe3O4) extracted from a polymetamorphosed, granulite-facies marble with the use of a focused ion beam. These magnetite crystals contain nanometer-scale, disk-shaped inclusions making this magnetite particularly attractive for investigating the capabilities of atom probe field ion microscopy (APFIM) for geological materials. Field ion microscope images of these magnetite crystals were obtained in which the observed size and morphology of the precipitates agree with previous results. Samples were analyzed in the energy compensated optical position-sensitive atom probe. Mass spectra were obtained in which peaks for singly ionized 16O, 56Fe and 56FeO and doubly ionized 54Fe, 56Fe and 57Fe peaks were fully resolved. Manganese and aluminum were observed in a limited analysis of a precipitate in an energy compensated position sensitive atom probe.

Concurrent chronic lymphocytic leukemia cutis and acute myelogenous leukemia cutis in a patient with untreated CLL

Patients who have chronic lymphocytic leukemia (CLL) are known to have a high frequency of second malignant neoplasms. However, acute myelogenous leukemia (AML) occurring concurrent with or after a diagnosis of CLL is extremely rare. In this article we report a case of AML developing in a 55-year-old male with a 6-year history of untreated CLL. The diagnosis was facilitated by touch preparation of a skin punch biopsy specimen. The patient presented with a two-week history of fever, weakness, anasarca, and a skin rash. Physical examination revealed pink to skin-colored firm papules, which coalesced into indurated plaques on his trunk, upper extremities, and face. The lesions, in combination with generalized edema, produced a leonine facies. Touch prep of the biopsy showed medium to large blasts, large monocytoid cells, and numerous small mature lymphocytes, providing the preliminary diagnosis of a second, previously undiagnosed myelomonocytic malignancy in this patient. The initial diagnosis was subsequently confirmed by histologic, cytochemical, immunohistochemical and flow cytometry studies. This is the first reported case of CLL with concurrent AML in which rapid touch prep of a skin punch biopsy facilitated diagnosis.

Immunohistochemical analysis of prostate specific antigen in breast cancer

The presence of immunoreactive prostate-specific antigen (IR-PSA) has been reported in breast cancers and has been suggested to confer a positive prognosis. However, recent large, well-controlled studies have found no significant prognostic value when IR-PSA positivity is examined as an independent variable, even when ultrasensitive immunofluorometric techniques are utilized. The present study, using indirect immunohistochemistry on 75 formalin-fixed, paraffin-embedded breast cancers shows PSA immunoreactivity in only seven of 75 cases (9%), suggesting that PSA positivity in breast carcinoma is not useful as a prognostic or tumor marker with hospital-based methods.

Analysis of anesthesia practice and needs in Louisiana

The Louisiana State University Health Sciences Center Department of Anesthesiology performed an analysis of anesthesia practice and needs within the State of Louisiana. The State of Louisiana currently has approximately 300 practicing anesthesiologists (physicians), 700 certified registered nurse anesthetists (CRNAs), and does not currently utilize anesthesiologist assistants (AAs). Approximately 500,000 anesthesia encounters occur annually in Louisiana. Although there is a recognized critical shortage of anesthesiologists nationally, this document will focus mainly on the issue of mid-level providers of anesthesia services. The overwhelming majority of surgical and obstetric procedures is performed using the anesthesia care team approach both nationally and in the State of Louisiana. Within the anesthesia care team model, the practice of certified registered nurse anesthetists and anesthesiologist assistants are interchangeable, and both would meet the need for mid-level anesthesia providers in the State of Louisiana.

Hydroxyurea therapy for pediatric patients with hemoglobin SC disease

PURPOSE

Hydroxyurea (HU) has laboratory and clinical efficacy in hemoglobin SS (HbSS) disease, but its benefits in hemoglobin SC (HbSC) disease are unknown. A recent adult HbSC disease pilot trial with HU therapy documented a modest laboratory benefit. Our goal was to evaluate the laboratory and clinical responses of selected pediatric patients with severe HbSC disease to HU therapy.

PATIENTS AND METHODS

As part of a retrospective case series, patients were selected from the Duke Pediatric Sickle Cell Program based on the frequency and severity of their vasoocclusive events or an episode of acute chest syndrome. Oral HU therapy was started as a single daily dose and increased to the maximally tolerated dose based on myelosuppression. Laboratory evaluation was performed at baseline and monthly thereafter. Once the maximum tolerated dose was reached, laboratory data were monitored bimonthly.

RESULTS

We treated six severely affected pediatric HbSC patients with HU for a median of 27 months. Mean corpuscular volume increased significantly (+26 fL) without change in hemoglobin concentration (-0.1 g/dL); neutrophils decreased significantly. Percentage of fetal hemoglobin (+8.5%) and percentage of F cells (+35.7%) increased significantly. Two experienced only mild and reversible toxicity.

CONCLUSION

The laboratory responses in our pediatric patients with HbSC disease were striking, with increases in percentage of fetal hemoglobin and percentage of F-cells approaching responses observed in adult and pediatric patients with HbSS disease. All patients improved clinically. Our findings demonstrate that HU therapy benefits pediatric patients with severe HbSC disease, although larger clinical trials of HU therapy in HbSC disease are warranted.

Ultrasound-guided internal jugular venous cannulation: an introduction for non-radiologists to a technique that is here to stay

The availability of relatively low-cost, portable ultrasound units has increased interest among non-radiologists in performing image-guided central venous cannulation, especially in high-risk patients. The essential elements of this relatively simple method of increasing the success and safety of internal jugular cannulation are presented.

The effect of knee angle on the external validity of isometric measures of lower body neuromuscular function

The aim of this study was to evaluate the effect of varying knee angle (120 degrees and 90 degrees) on the external validity of an isometric leg press test with reference to vertical jump performance. Isometric peak force (PF120 and PF90), rate of force development (RFD120 and RFD90), and maximum height reached with a squat jump and counter-movement jump were measured in 14 males. Although RFD120 was significantly correlated with squat jump and counter-movement jump performance (r = 0.71 and 0.69), and the correlations with PF120 approached statistical significance (r = 0.53 and 0.50), neither PF90 nor RFD90 was significantly related to vertical jump performance. Furthermore, although both RFD120 and PF120 were significantly different between the best five and the worst five jumpers, RFD90 and PF90 did not differentiate between individuals' vertical jump performance. We conclude that the choice of joint angle affects the external validity of isometric strength testing. Based on our results, we recommend accurate control of biomechanical specificity and assessment at different angles to find the position at which isometric strength testing is most comfortable.

Clinical features and management of Hadronyche envenomation in man

Using case reports and a review of the literature, the clinical features of envenomation by the genus of Australian funnel web spiders known as Hadronyche, are characterised. Five cases are reported here, including the first life-threatening envenomation by Hadronyche species 14 (the Port Macquarie funnel web). Two severe envenomations by Hadronyche cerberea (the Southern Tree funnel web) and one each by Hadronyche formidabilis (the Northern Tree funnel web) and Hadronyche infensa (the Darling Downs funnel web) are also described. The clinical experience of the authors' provided the five cases described in detail one of which has previously been reported in brief. Eight cases of Hadronyche envenomation from the literature (Medline 1966-1998 and Embase 1980-1998) were analysed in order to draw comparisons between this syndrome and the well described envenomation syndrome of Atrax robustus (the Sydney funnel web). Reports of funnel web spider antivenom use to Commonwealth Serum Laboratories (CSL) between 1995 and June 1998 were also examined. The biology of these dangerous spiders, their geographic distribution, venom characteristics and management issues are addressed. It is concluded that bites from at least six Hadronyche species have produced a life-threatening envenomation syndrome clinically indistinguishable from that of Atrax robustus. Atrax robustus derived antivenom is effective although antivenom requirements may be greater than for Atrax envenomation. Antivenom supplies are limited and sufficient stocks to treat a severe envenomation are unlikely to be found in any one institution. Pressure-immobilisation first aid is effective in delaying onset of envenomation, may enhance local inactivation of venom and early removal can result in rapid clinical deterioration.

Tooth-specific and person-level predictors of 24-month tooth loss among older adults

OBJECTIVES

To describe: (1) the 24-month incidence of tooth loss in a diverse sample of dentate adults; and (2) the clinical, attitudinal, behavioral, and sociodemographic correlates of tooth loss incidence.

METHODS

The Florida Dental Care Study is a prospective longitudinal cohort study of persons who at baseline had at least one tooth, were 45 years or older, and who resided in north Florida. An in-person interview and clinical examination were conducted at baseline and 24-months after baseline, with 6-monthly telephone interviews between those times. A two-level hierarchical generalized linear regression (logit model) was used to quantify tooth-specific and person-level factors simultaneously.

RESULTS

Of the 739 persons who attended for a 24-month examination, 24% lost one or more teeth during follow-up. Tooth loss was more common in persons with dental disease at baseline, incident dental signs or symptoms, those with negative attitudes toward dental care and dental health, those with limited financial resources, older adults, blacks, females, and problem-oriented users of dental care (as distinct from regular attenders). Although disease presence at baseline was a major factor associated with incident tooth loss, most diseased teeth were in fact still present 24 months after baseline.

CONCLUSIONS

Other than periodontal attachment loss, severe tooth mobility, and dental caries, no single factor was a dominant predictor of tooth loss; instead, numerous factors made statistically significant but small contributions to variation in tooth loss. Tooth loss apparently is the result of complex interactions among dental disease, incident dental signs and symptoms, tendency to use dental care in response to specific dental problems, dental attitudes, and ability to afford non-extraction treatment alternatives.

Translational control by an upstream open reading frame in the HER-2/neu transcript

Overexpression of the HER-2 (neu, erbB-2) receptor results in cellular transformation and is associated with a variety of human cancers. Multiple mechanisms, including gene amplification and transcriptional, post-transcriptional, and translational controls contribute to the regulation of HER-2 expression. One of the components of these regulatory mechanisms is a short upstream open reading frame (uORF) in the HER-2 mRNA that represses downstream translation in a variety of cell types. Here we explore the mechanism by which this uORF exerts its inhibitory effect. As judged by comparisons of protein and mRNA abundance and by polysomal distribution analyses, the uORF represses translation of the HER-2 cistron or of a heterologous reporter gene. Despite its conservation among mammalian species, the peptide sequence of the uORF is not required for this inhibitory effect. Rather, the majority of ribosomes that load on the HER-2 mRNA most likely translate the uORF and are then unable to reinitiate at the downstream AUG codon, in part due to the short intercistronic spacing. A minority of ribosomes gain access to the HER-2 initiation codon either by leaky scanning past the upstream AUG codon or by reinitiating after having translated the uORF despite the short intercistronic region. These results suggest that the HER-2 uORF controls synthesis of this oncoprotein by limiting ribosomal access to downstream initiation sites.

Consequences of differential residence designations for rural health policy research: the case of infant mortality

In 1991, members of the rural caucus proposed numerous bills designed to attenuate the rural-urban differences in health care delivery and health status. Implicit in the legislative process is the assumption that "rural America" differs systematically from "urban America." However, research has consistently demonstrated that there is not a single rural America but rather, those areas outside of the major metropolitan areas represent a complex mosaic of varying social and environmental settings. Rural communities differ in meaningful ways along a number of socioenvironmental parameters, and accordingly, health status indicators also differ across rural communities. Thus, health outcome statistics averaged across rural communities will often mask important disparities experienced by certain population groups. Policies based on these aggregate indicators may overlook the needs of the most disadvantaged. While a number of measures of rurality have emerged in the last decade, much of the information presented to policy-makers is either too aggregated (i.e., metropolitan-nonmetropolitan) to identify important differences across the range of communities, or it is gathered in agency-specific categories that are not comparable. The central question under examination in the current context is the possibility of distorting the picture of infant health status by aggregating the diverse rural locales of the United States. Empirical results indicate that when considering infant mortality, any rural disadvantage is contingent upon how 'rural' and 'urban' have been defined. Further, the results indicate that conclusions must be conditioned on other important sociodemographic parameters such as region of the country and race.

The role of race and residence in determining stage at diagnosis of breast cancer

Breast cancer kills more than 46,000 women each year. Previous research has found that minorities and those who reside in geographically remote settings are particularly vulnerable. However, virtually no research has been done on the potential "double jeopardy" faced by rural minority women. This research examines (1) the extent to which racial and residential differences contribute to differences in stage at diagnosis; (2) the existence of an interaction between race and residence, which may place black rural women at greater risk; and (3) the influence of both individual and structural characteristics on racial and residential differences. The findings indicate that rural black women are diagnosed with breast cancer much later than are black urban women or whites of either residence. A number of individual and structural variables were influential in predicting stage at diagnosis, yet none of these accounted entirely for racial differences.

The interactive effects of race and ethnicity and mother's residence on the adequacy of prenatal care

Adequate prenatal care is known to reduce the risks of low birth weight and neonatal death, yet nearly one quarter of all women giving birth in the United States receive delayed, inadequate or no prenatal care. This suboptimal use of prenatal care has contributed to rates of low birth weight and neonatal mortality higher than those in most other industrialized nations. This paper examines the relationships among race/ethnicity, residence, maternal sociodemographic and medical risk characteristics, and use of prenatal care in the United States. Using data from the National Maternal and Infant Health Survey, this study found important differences in prenatal care use by race/ethnicity and residence, as well as interactive effects of these variables. Single marital status, nonmetropolitan residence, poverty, low level of education, and no insurance were more strongly associated with inadequate prenatal care for whites and Hispanics than for blacks. Nonmetropolitan residents were more likely to receive inadequate care, regardless of race/ethnicity or sociodemographic characteristics. Predicted probabilities of prenatal care use by race/ethnicity and residence showed that, regardless of risk, nonmetropolitan Hispanic women had the highest probability of obtaining inadequate prenatal care. Results highlight the continued importance of race/ethnicity and rural residence in determining prenatal care use and the need to design interventions targeted to these populations.

The role of medical problems and behavioral risks in explaining patterns of prenatal care use among high-risk women

OBJECTIVE

To examine the associations between maternal medical conditions and behavioral risks and the patterns of prenatal care use among high-risk women.

DATA SOURCE/STUDY DESIGN

Data on over 25,000 high-risk deliveries to African American and white women using multinomial logistic regression to predict the odds of adequate-plus care relative to three other categories of care.

DATA COLLECTION/EXTRACTION METHODS

Data were extracted from records maintained by the University of Florida/Shands Hospital maternity clinic on all deliveries between 1987 and 1994; records for white and for African American women were subset to examine racial differences in medical conditions, health behaviors, and patterns of prenatal care use.

PRINCIPAL FINDINGS

Net of sociodemographic and fertility-related characteristics, African American and white women with late antepartum conditions and hypertension problems had significantly higher odds of receiving adequate-plus care, as well as no care or inadequate care, relative to adequate care. White women with gynecological disease and medical/surgical problems were significantly less likely to receive no care or inadequate care, as were African American women with gynecological disease.

CONCLUSIONS

Maternal medical conditions explain much but not all of the adequate-plus prenatal care use. More than 13 percent of African American women and 20 percent of white women with no reported medical problems or behavioral risks used adequate-plus care. Additional research is needed to understand this excess use and its possibilities in mediating birth outcomes.

Cell type-dependent and -independent control of HER-2/neu translation

Overexpression of the HER-2 oncogene occurs in a variety of human tumors, including 25-30% of breast carcinomas, and has been associated with an adverse prognosis. Amplification of the HER-2 gene is frequently detected in tumors, but by itself may not fully account for HER-2 overexpression since transcriptional and post-transcriptional mechanisms also regulate HER-2 protein synthesis. Our studies reveal that the efficiency of HER-2 translation differs between primary and transformed cells. In primary human fibroblasts and human mammary epithelial cells, the HER-2 mRNA is associated with monosome and small polysome fractions. In contrast, in BT474 and MCF-7 human breast cancer cell lines and in COS-7 cells the mRNA co-sedimented with larger polysomes, indicating that it is more efficiently translated in these transformed cells. Northern analysis revealed no detectable mRNA size difference, and nuclease S1 protection and sequence analyses showed no differences between the HER-2 transcript leader in primary cells compared to transformed human cells. The transcript leader in all cell types contains a short upstream open reading frame that is also conserved in other mammalian species. Transient transfection assays revealed that the HER-2 transcript leader repressed downstream translation approximately five-fold in both primary and transformed cells and mutation of the upstream initiation codon alleviated most of the inhibitory effect. These results indicate that HER2 expression is translationally controlled both by a short upstream open reading frame that represses HER-2 translation in a cell type-independent manner, and by a distinct cell type-dependent mechanism that increases translational efficiency of HER-2 in transformed cells.

Norplant selection and satisfaction among low-income women

OBJECTIVES

This study examined correlates of Norplant selection and satisfaction among low-income women.

METHODS

Interviews were completed in family planning clinics in 4 Florida counties with 1152 Norplant users and 1268 nonusers, with follow-up interviews with a subsample up to 1 year later. Logistic regression models estimated the associations of socio-demographic and medical characteristics with Norplant selection and method satisfaction.

RESULTS

Odds ratios for Norplant selection were significantly greater among women who planned to have children in 5 or more years, those who were "offered" Norplant, those who lived in Palm Beach County, those who were using drugs, and those who were Medicaid clients. Women younger than 17 and those who learned about Norplant from a friend were twice as likely as others to select Norplant. Ninety-two percent of Norplant users were satisfied with the method; women with side effects and those who felt pressure to select a method were significantly less likely than others to be satisfied.

CONCLUSIONS

Norplant provides an acceptable and satisfying method of birth control for many low-income women. Proper counseling about all methods of birth control and about Norplant's side effects remains critical to the appropriate delivery of this method.

Racial differences in adolescent drug use: the impact of religion

Contrary to popular stereotypes, current studies of adolescent populations suggest that Black teens are less likely to use illicit drugs than are White teens. This study investigates the extent to which differences in religiosity are responsible for racial differences in drug use. Using data from a national survey of United States high school seniors, our results indicate that religion does provide some protection from drug use by adolescents. However, religiosity has less of an impact on the drug use of Black adolescents, perhaps as a result of the diverse roles of the Black church.

Mature micromegakaryocytes: an unusual developmental pattern in term infants

We sought to gain perspective on platelet production in the fetus and the newborn by counting and characterizing megakaryocytes from available cord blood. Elutriation was used to isolate circulating megakaryocytes from umbilical arteries and veins obtained at scheduled caesarean sections of nine normal term fetuses. Megakaryocytes were identified by established criteria, their diameters measured, and maturation stages recorded. Large numbers of megakaryocytes, mostly mature, were found in both the umbilical arteries and veins, many times more than previously observed circulating in adult blood. In term infants more than a third of the mature megakaryocytes had unusually decreased nuclear lobation and were dwarf cells with diameters as small as 13 microns, which we considered to be micromegakaryocytes. The atypicality of these small but mature cells is seen as merely a leftward skewing in the development of megakaryocyte ploidies. We believe that in normal fetuses the extent of megakaryocyte ploidization and development is distinctive and probably regulated differently to the adult pattern.

Hispanic subgroup differences in prenatal care

Within SES categories in the United States, racial and ethnic minorities generally fare less well on a variety of health-related indicators than do majority groups. Important differences exist within subgroups, however, and at present, these differences are poorly understood. In this paper we address Hispanic subgroup (Cuban American, Mexican American. Puerto Rican, and Central/South American) differences in utilization of prenatal care. Data from the 1986 and 1987 national Linked Birth/Infant Death files are used to assess patterns of prenatal care utilization across subgroups. Using Kotelchuck's Adequacy of Prenatal Care Utilization Index, we find that when controlling for other factors, Cuban American and Puerto Rican women are more likely to obtain adequate care than are Hispanic women of Mexican or Central/South American origin. Other factors important in understanding utilization patterns include marital status, education level, birthplace, and region of the country. We conclude with a discussion of the relatively weak link between prenatal care and birth outcomes and identify important cultural factors that may be important in understanding why this relationship is not stronger.

Frequency and risk factors for voice problems in teachers of singing and control subjects

Using a questionnaire format, 125 teachers of singing and 49 control subjects indicated whether they had a current or past voice problem, and provided information about their demographic characteristics, voice use patterns, and medication use. The results revealed similar rates of current voice problems reported by the two subject groups. However, teachers of singing were considerably more likely to report ever having had a voice problem than controls (64 vs. 33%). Risk factors were similar for the two groups. Dehydrating medications and a report of a past voice problem both increased the likelihood of perceiving a current problem, by a factor of three and five, respectively. Females were twice as likely to report a past voice problem as males, and younger subjects were slightly more likely to report a past problem as compared with older subjects. The implications of the findings are discussed from a theoretical as well as pragmatic perspective.

Prenatal care use in nonmetropolitan and metropolitan America: racial/ethnic differences

Pregnant women in nonmetropolitan communities are believed to use prenatal care services at lower rates than are metropolitan residents due to higher levels of poverty, lower levels of insurance coverage, and declining numbers of local hospitals and physicians. Yet scarce data exist on actual patterns of prenatal care use in nonmetropolitan areas. This study provides national estimates of prenatal care use among African American, White, and Hispanic women who delivered in 1988 in non-metropolitan and metropolitan areas of the United States. This study finds that nonmetropolitan residents are no more likely than metropolitan residents to go without care, to enter care late, or to make fewer visits. Nonmetropolitan residents are more likely to receive "inadequate" prenatal care as measured by the Kotelchuck Adequacy of Prenatal Care Utilization Index, with Hispanic residents having the highest rates of inadequate care. These findings are consistent with recent state-level reports, and they suggest the need to target prenatal care policies for populations in greatest need.

Variations in rural hospital costs: effects of market concentration and location

This article explores two neglected questions: (1) Does the relationship between hospital concentration and costs vary between urban and rural markets? and (2) Do hospital costs in non-metropolitan areas vary with rurality? Covariance model results using 1992 data reveal that: (1) Although metropolitan and urban markets exhibit a negative relationship between hospital average costs and market concentration, non-metropolitan and rural markets fail to exhibit any relationship between costs and concentration; and (2) among non-metropolitan hospitals, only hospitals located in single-hospital communities have lower costs than their counterparts in multiple-hospital communities, once other factors are held constant.

The micronuclear gene encoding beta-telomere binding protein in Oxytricha nova

The micronuclear version of the gene encoding beta-telomere binding protein (beta-TBP) in Oxytricha nova has been sequenced and compared to the macronuclear beta-TBP gene, previously described. The micronuclear gene contains three AT-rich internal eliminated sequences (IES) of 37, 40, and 43 bp and four macronuclear destined sequences (MDS). The IES interrupt the gene once near the 5' end of the coding region and twice in the 3' trailer downstream from the TGA stop codon. The sequences of the micronuclear and macronuclear genes are colinear. Thus, the micronuclear beta-TBP gene is not scrambled, which contrasts with the highly scrambled state among the 14 MDS in the micronuclear alpha-TBP gene.

The triple-helical region of human type XIX collagen consists of multiple collagenous subdomains and exhibits limited sequence homology to alpha 1(XVI)

We previously isolated a clone from a human rhabdomyosarcoma (RH) cDNA library coding for a collagen chain different from those constituting the 18 reported types (Myers, J. C., Sun, M. J., D'Ippolito, J. A., Jabs, E. W., Neilson, E. G., and Dion, A. S. (1993) Gene (Amst.) 123, 211-217). The sequence translated to a 186-amino acid noncollagenous region, a 524-residue three-subdomain collagenous region, and a presumed 8-amino acid COOH-terminal peptide. To further elucidate the primary structure of this collagen, we have now determined the sequence of additional cDNA clones. Overlapping 3' clones, found to diverge exactly where the noncollagenous 8-residue COOH sequence began, encode two additional collagenous subdomains of 168 and 70 residues and a 19-residue COOH-terminal peptide. Analysis of genomic DNA spanning the region in question revealed several 45- and 51-base pair exons linked by 4 introns totaling over 5 kilobases (kb). A 2-kb intron, absent from the clones coding for the extended collagenous region, was used in Northern blot hybridization to detect an apparently prevalent splicing intermediate 2 kb larger than the major 12.4-kb RH transcript. Therefore, the triple-helical region of this collagen chain is likely to be composed of 832 amino acids divided into five collagenous subdomains separated by 20-44 residue interruptions. Two interruptions are similar in sequence and position to those located in the type XVI chain. Furthermore, the arrangement of 2 cysteines near the COOH terminus and two imperfections in collagenous subdomain 1 are conserved in the related subclass composed of type IX, XII, XIV, and XVI collagens. However, in contrast to the COOH-terminal interchain bridging in this latter collagen group, molecular modeling strongly predicts that the cysteines in RH collagen participate in intrachain disulfide bonds. Taken together, the data clearly show that RH collagen does not represent another chain of one of the known collagen types. We propose that it be designated the alpha 1 chain of type XIX collagen.

Expression of glycosylated and nonglycosylated human transferrin in mammalian cells. Characterization of the recombinant proteins with comparison to three commercially available transferrins

The coding sequence for human serum transferrin was assembled from restriction fragments derived from a full-length cDNA clone isolated from a human liver cDNA library. The assembled clone was inserted into the expression vector pNUT and stably transfected into transformed baby hamster kidney (BHK) cells, leading to secretion of up to 125 mg/L recombinant protein into the tissue culture medium. As judged by mobility on NaDodSO4-PAGE, immunoreactivity, spectral properties (indicative of correct folding and iron binding), and the ability to bind to receptors on a human cell line, initial studies showed that the recombinant transferrin, is identical to three commercial human serum transferrin samples. Electrospray mass spectrometry (ESMS), anion-exchange chromatography, and urea gel analysis showed that the recombinant protein has an extremely complex carbohydrate pattern with 16 separate masses ranging from 78,833 to 80,802 daltons. Mutation of the two asparagine carbohydrate linkage sites to aspartic acid residues led to the expression and secretion of up to 25 mg/L nonglycosylated transferrin. ESMS, anion-exchange chromatography, and urea gel analysis showed a single molecular species that was consistent with the expected theoretical mass of 75,143 daltons. In equilibrium binding experiments, the nonglycosylated mutant bound to HeLa S3 cells with the same avidity and to the same extent as the glycosylated protein and the three commercial samples. These studies demonstrate conclusively that carbohydrate has no role in this function.

The effectiveness of Florida's "Improved Pregnancy Outcome" program

The development of a national program to assure access to prenatal care for all women, regardless of income, is believed to be an effective means of reducing low birthweight and neonatal mortality in the U.S. Yet scarce empirical evidence concerning the effectiveness of large-scale prenatal care programs is available. This paper summarizes an evaluation of a statewide public prenatal care program which grew out of the federal Improved Pregnancy Outcome (IPO) project. Using linked birth and infant death-certificate data, and IPO program records from a four-year period (1985-1988), this study compares the neonatal mortality rates of participants of Florida's IPO program with those of a matched comparison group. The results indicate an inverse relationship between IPO participation and the risk of neonatal mortality in a low-income population. These findings suggest that large-scale prenatal care programs can be effective in improving birth outcomes.

Uncompensated care provided by private practice physicians in Florida

While a great deal of attention has been paid in recent years to establishing the magnitude and characteristics of uncompensated care in hospitals, comparatively little research has been undertaken to study physician uncompensated care. This article reports the results of a prospective patient-specific study of uncompensated care in Florida. Of 4,042 cases examined, 26.2 percent had charges voluntarily reduced below the usual and customary charge at the time of service. However, only 13.5 percent of those reductions were attributed to charity. Overall, 10.4 percent of the total billed amount was left unresolved. When payment source was considered, it was found that self-pay patients accounted for 30.6 percent of the cases but accounted for 52.0 percent of the unresolved amounts. Further analysis indicated that the self-pay patients were 35.5 times more likely to leave an outstanding balance than individuals with some type of insurance coverage. Odds of unresolved balances were also calculated as a function of income, specialty type, practice size, and type of visit.

Extracorporeal membrane oxygenation therapy in neonates with septic shock

Neonatal septic shock has significant morbidity and mortality with current therapeutic measures. At Children's National Medical Center, from June 1984 to October 1986, 10 of 100 patients treated with venoarterial extracorporeal membrane oxygenation (ECMO) had a documented diagnosis of septic shock. All of these infants fulfilled criteria consistent with 80% mortality using conventional intensive medical management. However, the survival rate for the septic neonates in this study was 100%. Compared with other groups of infants treated with ECMO, these septic neonates required significantly more ventilatory support after ECMO and had a higher incidence of chronic lung disease (30% v 12%). The septic neonates were also at higher risk for intracranial hemorrhage than the other infants treated with ECMO (40% v 26%). The necessity for prolonged intubation after ECMO for patients with septic shock suggests that this condition may be associated with additional structural damage not seen with meconium aspiration syndrome or respiratory distress syndrome. Nevertheless, for neonatal patients with septic shock unresponsive to conventional medical management, ECMO must be considered a viable alternative treatment.

Determinants of primary caregiver stress and burden: area of residence and the caregiving networks of frail elders

This research examines the association among characteristics of the caregiving network, primary caregiver stress and burden, and area of residence. The purpose is two-fold: to determine whether the structure of the relationship between the caregiving network, and stress and burden is uniform across rural, small city, and urban samples; and, to assess whether stress and burden are explained by a similar set of variables within area of residence categories. The data are drawn from a matched sample of 1,388 impaired elders and their primary caregivers from the 1982 National Long-Term Care Survey and the National Survey of Informal Caregivers. In general, the analysis shows that several characteristics of the care-receiver and the primary caregiver have a differential effect on stress and burden across residential categories, and that, within rural, small city, and urban samples, the determinants of stress and burden are not homogeneous. When the frail elder is able to reciprocate by doing chores, babysitting, or providing some other type of assistance for the primary caregiver, however, both stress and burden are reduced in all three residential categories. Similarly, the increased provision of assistance with instrumental activities of daily living by the primary caregiver uniformly increases stress and burden. These findings suggest that interventions designed to alleviate primary caregiver stress and burden may be able to have some common components, but may also need to be tailored in some ways to specific residential environments.