Modification of Shape Memory Polymer Foams Using Tungsten, Aluminum Oxide, and Silicon Dioxide Nanoparticles.

Shape memory polymer (SMP) foams were synthesized with three different nanoparticles (tungsten, silicon dioxide, and aluminum oxide) for embolization of cerebral aneurysms. Ultra-low density SMP foams have previously been utilized for aneurysm occlusion, resulting in a rapid, stable thrombus. However, the small cross section of foam struts can potentially lead to fracture and particulate generation, which would be a serious adverse event for an embolic device. The goal of this study was to improve the mechanical properties of the system by physically incorporating fillers into the SMP matrix. Thermal and mechanical characterization suggested minimal changes in thermal transition of the SMP nanocomposites and improved mechanical strength and toughness for systems with low filler content. Actuation profiles of the three polymer systems were tuned with filler type and content, resulting in faster SMP foam actuation for nanocomposites containing higher filler content. Additionally, thermal stability of the SMP nanocomposites improved with increasing filler concentration, and particulate count remained well below accepted standard limits for all systems. Extraction studies demonstrated little release of silicon dioxide and aluminum oxide from the bulk over 16 days. Tungstun release increased over the 16 day examination period, with a maximum measured concentration of approxiately 2.87 µg/mL. The SMP nanocomposites developed through this research have the potential for use in medical devices due to their tailorable mechanical properties, thermal resisitivity, and actuation profiles.

Repeated fear-induced diurnal rhythm disruptions predict PTSD-like sensitized physiological acute stress responses in F344 rats.

AIM: To identify objective factors that can predict future sensitized stress responses, thus allowing for effective intervention prior to developing sensitization and subsequent stress-related disorders, including post-traumatic stress disorder (PTSD). METHODS: Adult male F344 rats implanted with biotelemetry devices were exposed to repeated conditioned fear or control conditions for 22 days followed by exposure to either no, mild or severe acute stress on day 23. Diurnal rhythms of locomotor activity (LA), heart rate (HR) and core body temperature (CBT) were biotelemetrically monitored throughout the study. In a subset of rat not implanted, corticosterone and indices of chronic stress were measured immediately following stress. RESULTS: Rats exposed to repeated fear had fear-evoked increases in behavioural freezing and HR/CBT during exposure to the fear environment and displayed indices of chronic stress. Repeated fear produced flattening of diurnal rhythms in LA, HR and CBT. Repeated fear did not sensitize the corticosterone response to acute stress, but produced sensitized HR/CBT responses following acute stress, relative to the effect of acute stress in the absence of a history of repeated fear. Greater diurnal rhythm disruptions during repeated fear predicted sensitized acute stress-induced physiological responses. Rats exposed to repeated fear also displayed flattened diurnal LA and basal increases in HR. CONCLUSIONS: Exposure to repeated fear produces outcomes consistent with those observed in PTSD. The results suggest that diurnal rhythm disruptions during chronic stressors may help predict sensitized physiological stress responses following traumatic events. Monitoring diurnal disruptions during repeated stress may thus help predict susceptibility to PTSD.

Learned helplessness is independent of levels of brain-derived neurotrophic factor in the hippocampus.

Reduced levels of brain-derived neurotrophic factor (BDNF) in the hippocampus have been implicated in human affective disorders and behavioral stress responses. The current studies examined the role of BDNF in the behavioral consequences of inescapable stress, or learned helplessness. Inescapable stress decreased BDNF mRNA and protein in the hippocampus of sedentary rats. Rats allowed voluntary access to running wheels for either 3 or 6 weeks prior to exposure to stress were protected against stress-induced reductions of hippocampal BDNF protein. The observed prevention of stress-induced deceases in BDNF, however, occurred in a time course inconsistent with the prevention of learned helplessness by wheel running, which is evident following 6 weeks, but not 3 weeks, of wheel running. BDNF suppression in physically active rats was produced by administering a single injection of the selective serotonin reuptake inhibitor fluoxetine (10 mg/kg) just prior to stress. Despite reduced levels of hippocampal BDNF mRNA following stress, physically active rats given the combination of fluoxetine and stress remained resistant against learned helplessness. Sedentary rats given both fluoxetine and stress still demonstrated typical learned helplessness behaviors. Fluoxetine by itself reduced BDNF mRNA in sedentary rats only, but did not affect freezing or escape learning 24 h later. Finally, bilateral injections of BDNF (1 mug) into the dentate gyrus prior to stress prevented stress-induced reductions of hippocampal BDNF but did not prevent learned helplessness in sedentary rats. These data indicate that learned helplessness behaviors are independent of the presence or absence of hippocampal BDNF because blocking inescapable stress-induced BDNF suppression does not always prevent learned helplessness, and learned helplessness does not always occur in the presence of reduced BDNF. Results also suggest that the prevention of stress-induced hippocampal BDNF suppression is not necessary for the protective effect of wheel running against learned helplessness.

Ascertainment of intimate partner violence using two abuse measurement frameworks.

OBJECTIVE: To estimate prevalence of intimate partner violence (IPV) according to two abuse ascertainment tools, and agreement between the tools. METHODS: 2504 women randomly selected from a health maintenance organization were asked about IPV exposure in their most recent intimate relationship using five questions on physical and sexual abuse, and fear due to partner's threats and controlling behavior from the Behavioral Risk Factor Surveillance Survey (BRFSS) and 10 questions from the Women's Experience with Battering (WEB) scale. IPV prevalence was estimated according to the BRFSS and WEB, and the proportion of women who were WEB+/BRFSS+, WEB-/BRFSS-, WEB-/BRFSS+, and WEB+/BRFSS-. RESULTS: In their most recent relationship, 14.7% of women reported abuse of any type on the BRFSS versus 7.0% on the WEB scale. In direct comparisons of the WEB and BRFSS questions, a higher percentage of abused women reported any IPV on the five BRFSS questions (88.4%) compared to the 10 WEB questions (42.0%). However, both the BRFSS and WEB identified some women as abused that would have been missed by the other instrument. CONCLUSIONS: Intimate partner violence prevalence depends on how women are asked about abuse. Resources permitting, more than one abuse ascertainment strategy (for example, both the BRFSS and WEB questions) should be tried in order to broadly identify as many women as possible who interpret themselves as abused.

Rapid ecotoxicological testing using transformed BF-2 cells incorporating a luminescent reporter gene.

Since there is an ethical need to minimise the experimental use of higher organisms such as fish, especially those used in acute toxicity testing, fish cells are considered to be useful surrogates for fish in toxicity screening. The use of fish cell lines in conventional bioassays such as neutral red retention assays is however labour intensive, lengthy and costly. The use of luminescent reporter genes has been explored in our laboratory. In this study, a transfected BF-2 cell line (BF-2/luc1) was used for rapid toxicity testing on selected chemicals and results were compared with those obtained with in vivo fish testing and in vitro fish cell neutral red retention assays. The effect of temperature on the sensitivity of BF-2/luc1 was also investigated. BF-2/luc1 cells were harvested and suspended in PBS at 2.5-3.0x10(6)cells/ml. Individual aliquots of the suspended cells (40 microl each) were incubated for either 0.5 or 6 h at room temperature (22 degrees C) in the presence or absence of the toxicants. Bioluminescence was assayed using 17.5 microl Brightglo luciferase reagent which lysed the cells and provided the substrate luciferin. Luminescence was measured in a luminometer (Turner TD 20/20). The EC50 values obtained from BF-2/luc1 cells (0.5-6 h) generally compared well with the LC50 values (24-96 h) obtained from the in vivo fish tests on a range of species. The present study also showed that BF-2/luc1 cell sensitivity increased significantly when incubation temperature during toxicant exposure increased from 15 to 35 degrees C. The use of luminescent reporter genes in monitoring fish cells offers the possible advantages of increased sensitivity over the neutral red retention assay and a more rapid test to replace stain based bioassays, and provides a rapid screening method that could reduce the need for acute fish toxicity testing.

Ability of parents to recall the injuries of their young children.

OBJECTIVE: To estimate the ability of parents to recall the injuries of their children. DESIGN: Comparison of parent recall with computerized medical records. SETTING: A health maintenance organization in Washington State during 2003. SUBJECTS: Parents of children younger than 6 years. MAIN OUTCOME MEASURES: The ratio of recalled injuries to injuries in computerized data. RESULTS: Telephone interviews were completed with a parent of 1672 young children who had computerized medical data for at least one injury in the last year. Counting the three most recent treated injuries, the 1672 children had 1896 separate new injuries in the year before interview and parents recalled 1150 of these: recall ratio 0.61 (95% confidence interval (CI) 0.58 to 0.63). The recall ratio decreased from 0.82 (95% CI 0.79 to 0.85) for injuries one day before interview to 0.37 (95% CI 0.32 to 0.40) at 365 days before interview. For 341 major injuries the recall ratio was 0.80 (95% CI 0.76 to 0.84), for 202 minor injuries treated in an emergency department or hospital it was 0.77 (95% CI 0.71 to 0.82), for 597 minor injuries treated in urgent care it was 0.70 (95% CI 0.65 to 0.73), and for 756 minor injuries treated in a clinic it was 0.43 (95% CI 0.39 to 0.47). CONCLUSIONS: Recall decreased with time. Recall was best for major injuries, intermediate for minor injuries treated in a hospital, emergency department, or urgent care center, and worst for minor injuries treated in a clinic.

Spectral power density calculations for pulsed Doppler.

Range-gated pulsed Doppler can be used to make localized velocity measurements within a blood vessel. A spectral flow profile can be created by stepping a sufficiently small sample volume across the lumen, but no set of spectra will correspond directly to the true velocity profile. Spectral flow profiles are affected by a complex interplay between different sources of spectral broadening. In this study we developed a systematic theoretical method which allows spectral power density functions to be calculated under a very wide range of conditions, and used it to obtain simulated flow spectra. The model was formulated analytically. It is based on the weighted-volume approach and incorporates, through the concept of a spread function, the intrinsic spectral broadening associated with a focused transducer. It can be applied for arbitrary values of the spread parameter; for non-uniform beam profiles; with maximal (continuous wave-type) or minimal (pulse wave-type) range-gated sample volumes; and for beams that intersect the flow tube axis, or are off centre. Results are presented for a Gaussian beam and parabolic flow. Simulated spectral flow profiles are given which illustrate how a profile's appearance can be altered by the different sources of spectral broadening.

Flow spectra from spectral power density calculations for pulsed Doppler.

Range gated pulsed Doppler can be used to make localized velocity measurements within a blood vessel. Both the transducer and the sample volume are of finite size, and this prohibits the measurement of velocity at a point. A spectral flow profile can be created by stepping a sufficiently small sample volume across the lumen of a vessel. However no such set of spectra will correspond directly to the true velocity profile. In this study we developed a systematic theoretical treatment which allows Doppler spectral power density (SPD) functions to be calculated under a very wide range of conditions. Simulated flow spectra were created from sets of these spectra. The model is based on the beam intensity weighted volume method and incorporates, through the idea of a spread function, Guidi's individual flow line spectrum. Our method can be applied for different spread functions; with beam profiles which are uniform, Gaussian or arbitrarily narrow (needle beam); with range gated sample volumes which can be maximal (CW-type) or minimal (PW-type); and for beams which intersect the flow tube axis, or are off centre. Under all conditions we find the spread function parameter k, equal to the ratio of the central Doppler shift to half the bandwidth, plays a key role. After formulating the model analytically, we sought simplifications to allow results to be obtained from simple, practical formulae. Spread and unspread SPD functions are in most cases given as single integrals which contain measurable physical parameters and can be easily evaluated numerically. Model results are presented for flow spectra of parabolic flow, illustrating the interplay between different factors in determining the appearance of spectral flow profiles.

Psychiatric illness and subsequent traumatic brain injury: a case control study.

OBJECTIVE: To determine whether psychiatric illness is a risk factor for subsequent traumatic brain injury (TBI). METHODS: Case control study in a large staff model health maintenance organisation in western Washington State. Patients with TBI, determined by International classification of diseases, 9th revision, clinical modification (ICD-9-CM) diagnoses, were 1440 health plan members who had TBI diagnosed in 1993 and who had been enrolled in the previous year, during which no TBI was ascertained. Three health plan members were randomly selected as control subjects, matched by age, sex, and reference date. Psychiatric illness in the year before the TBI reference date was determined by using computerised records of ICD-9-CM diagnoses, psychiatric medication prescriptions, and utilisation of a psychiatric service. RESULTS: For those with a psychiatric diagnosis in the year before the reference date, the adjusted relative risk for TBI was 1.7 (95% confidence interval (CI) 1.4 to 2.0) compared with those without a psychiatric diagnosis. Patients who had filled a psychiatric medication prescription had an adjusted relative risk for TBI of 1.6 (95% CI 1.2 to 2.1) compared with those who had not filled a psychiatric medication prescription. Patients who had utilised psychiatric services had an adjusted relative risk for TBI of 1.3 (95% CI 1.0 to 1.6) compared with those who had not utilised psychiatric services. The adjusted relative risk for TBI for patients with psychiatric illness determined by any of the three psychiatric indicators was 1.6 (95% CI 1.4 to 1.9) compared with those without any psychiatric indicator. CONCLUSION: Psychiatric illness appears to be associated with an increased risk for TBI.

Methods for conducting systematic reviews of the evidence of effectiveness and economic efficiency of interventions to reduce injuries to motor vehicle occupants.

BACKGROUND: Motor vehicle occupant injury prevention is included in the Guide to Community Preventive Services because of the enormous health impact of these largely preventable injuries. This article describes the methods for conducting systematic literature reviews of interventions for three key injury prevention strategies: increasing child safety seat use, increasing safety belt use, and decreasing alcohol-impaired driving. METHODS: Systematic review methods follow those established for the Guide to Community Preventive Services and include: (1) recruiting a systematic review development team, (2) developing a conceptual approach for selecting interventions and for selecting outcomes that define the success of the interventions, (3) defining and conducting a search for evidence of effectiveness, (4) evaluating and summarizing the body of evidence of effectiveness, (5) evaluating other potential beneficial and harmful effects of the interventions, (6) evaluating economic efficiency, (7) identifying implementation barriers, (8) translating the strength of the evidence into recommendations, and (9) identifying and summarizing research gaps. RESULTS: The systematic review development team evaluated 13 interventions for the three strategic areas. More than 10,000 titles and abstracts were identified and screened; of these, 277 met the a priori systematic review inclusion criteria. Systematic review findings for each of the 13 interventions are provided in the accompanying articles in this supplement. CONCLUSION: The general methods established for conducting systematic reviews for the Guide to Community Preventive Services were successfully applied to interventions to reduce injuries to motor vehicle occupants.

Reviews of evidence regarding interventions to increase use of child safety seats.

BACKGROUND: In 1998, nearly 600 child occupants of motor vehicles aged younger than 4 years died in motor vehicle crashes. Yet approximately 29% of children aged 4 years and younger do not ride in appropriate child safety seat restraints, which, when correctly installed and used, reduce the need for hospitalization in this age group by 69% and the risk of death by approximately 70% for infants and by 47% to 54% for toddlers (aged 1 to 4 years). METHODS: The systematic review development team reviewed the scientific evidence of effectiveness for five interventions to increase child safety seat use. For each intervention, changes in the use of child safety seats or injury rates were the outcome measures evaluated to determine the success of the intervention. Database searching was concluded in March 1998. More than 3500 citations were screened; of these citations, 72 met the inclusion criteria for the reviews. RESULTS: The systematic review process identified strong evidence of effectiveness for child safety seat laws and distribution plus education programs. In addition, community-wide information plus enhanced enforcement campaigns and incentive plus education programs had sufficient evidence of effectiveness. Insufficient evidence was identified for education-only programs aimed at parents, young children, healthcare professionals, or law enforcement personnel. CONCLUSIONS: Evidence is available about the effectiveness of four of the five interventions we reviewed. This scientific evidence, along with the accompanying recommendations of the Task Force elsewhere in this supplement, can be a powerful tool for securing the resources and commitment required to implement these strategies.

Reviews of evidence regarding interventions to increase the use of safety belts.

BACKGROUND: The use of safety belts is the single most effective means of reducing fatal and nonfatal injuries in motor vehicle crashes. If all motor vehicle occupants consistently wore safety belts, an estimated 9553 deaths would have been prevented in 1999 alone. METHODS: The Guide to Community Preventive Services's methods for systematic reviews were used to evaluate the effectiveness of three interventions to increase safety belt use. Effectiveness was assessed on the basis of changes in safety belt use and number of crash-related injuries. RESULTS: Strong evidence was found for the effectiveness of safety belt laws in general and for the incremental effectiveness of primary safety belt laws relative to secondary laws. Strong evidence for the effectiveness of enhanced enforcement programs for safety belt laws was also found. Additional information is provided about the applicability, other effects, and barriers to implementation of these interventions. CONCLUSIONS: These reviews form the basis of the recommendations by the Task Force on Community Preventive Services presented elsewhere in this supplement. They can help decision makers identify and implement effective interventions that fit within an overall strategy to increase safety belt use.

Reviews of evidence regarding interventions to reduce alcohol-impaired driving.

BACKGROUND: Alcohol-related motor vehicle crashes are a major public health problem, resulting in 15,786 deaths and more than 300,000 injuries in 1999. This report presents the results of systematic reviews of the effectiveness and economic efficiency of selected population-based interventions to reduce alcohol-impaired driving. METHODS: The Guide to Community Preventive Services's methods for systematic reviews were used to evaluate the effectiveness of five interventions to decrease alcohol-impaired driving, using changes in alcohol-related crashes as the primary outcome measure. RESULTS: Strong evidence was found for the effectiveness of .08 blood alcohol concentration laws, minimum legal drinking age laws, and sobriety checkpoints. Sufficient evidence was found for the effectiveness of lower blood alcohol concentration laws for young and inexperienced drivers and of intervention training programs for servers of alcoholic beverages. Additional information is provided about the applicability, other effects, and barriers to implementation of these interventions. CONCLUSION: These reviews form the basis of the recommendations by the Task Force on Community Preventive Services presented elsewhere in this supplement. They can help decision makers identify and implement effective interventions that fit within an overall strategy to prevent impaired driving.

The risk of seizures after receipt of whole-cell pertussis or measles, mumps, and rubella vaccine.

BACKGROUND: The administration of the diphtheria and tetanus toxoids and whole-cell pertussis (DTP) vaccine and measles, mumps, and rubella (MMR) vaccine has been associated with adverse neurologic events, including seizures. We studied the relation between these vaccinations and the risk of a first seizure, subsequent seizures, and neurodevelopmental disability in children. METHODS: This cohort study was conducted at four large health maintenance organizations and included reviews of the medical records of children with seizures. We calculated the relative risks of febrile and nonfebrile seizures among 679,942 children after 340,386 vaccinations with DTP vaccine, 137,457 vaccinations with MMR vaccine, or no recent vaccination. Children who had febrile seizures after vaccination were followed to identify the risk of subsequent seizures and other neurologic disabilities. RESULTS: Receipt of DTP vaccine was associated with an increased risk of febrile seizures only on the day of vaccination (adjusted relative risk, 5.70; 95 percent confidence interval, 1.98 to 16.42). Receipt of MMR vaccine was associated with an increased risk of febrile seizures 8 to 14 days after vaccination (relative risk, 2.83; 95 percent confidence interval, 1.44 to 5.55). Neither vaccination was associated with an increased risk of nonfebrile seizures. Analyses of automated data alone gave results similar to the analyses of the data from medical-record reviews. The number of febrile seizures attributable to the administration of DTP and MMR vaccines was estimated to be 6 to 9 and 25 to 34 per 100,000 children, respectively. As compared with other children with febrile seizures that were not associated with vaccination, the children who had febrile seizures after vaccination were not found to be at higher risk for subsequent seizures or neurodevelopmental disabilities. CONCLUSIONS: There are significantly elevated risks of febrile seizures on the day of receipt of DTP vaccine and 8 to 14 days after the receipt of MMR vaccine, but these risks do not appear to be associated with any long-term, adverse consequences.

HIV prevention in primary care: impact of a clinical intervention.

Discomfort, lack of confidence in skills, and environmental constraints may cause primary care providers to miss opportunities to discuss human immunodeficiency virus (HIV) risk with patients. We used a systems approach to address both intrapersonal and environmental barriers to HIV risk assessment and prevention counseling in a managed care clinical setting. The design was one-group pretest/posttest. The study took place in two primary care clinics of a large Pacific Northwest managed care organization. Participants (n = 49) included physicians, physician assistants, nurse practitioners, registered nurses, and social workers. The intervention included training, clarification of provider/staff roles, assess to tools and materials, and reminders/reinforcers. Outcome measures were provider attitudes, beliefs, outcome expectations, knowledge, confidence in skills, and perceived supports and barriers, measured by written pretest/posttest surveys administered 12 months apart. Seven months after the most intensive part of the intervention, providers' attitudes and beliefs were more favorable to HIV risk assessment and prevention counseling. They were less likely to express frustration with high-risk patients (decrease from 100% to 79% agreement, p = 0.001) and more confident that their advice would be effective with gay men and single adult heterosexuals (p = 0.002 and 0.005, respectively). They reported more confidence in their training in sexual history taking (p = 0.0003) and their skills assessing readiness for change (p = 0.007), and more support in practice environments. This study demonstrated that it is possible to affect important personal and environmental factors that influence primary care providers' HIV prevention behavior using an interactive, real-world systems approach. Further research is needed on providers' impact on patient behavior.

Impact of the change in polio vaccination schedule on immunization coverage rates: a study in two large health maintenance organizations.

OBJECTIVE: In January 1997, one of the most significant changes to United States vaccine policy occurred when polio immunization guidelines changed to recommend a schedule containing inactivated polio vaccine (IPV). There were concerns that parent or physician reluctance to accept IPV into the routine childhood immunization schedule would lead to lowered coverage. We determined whether adoption of an IPV schedule had a negative impact on immunization coverage. DESIGN: A cohort study of 2 large health maintenance organizations (HMOs), Group Health Cooperative and Kaiser Permanente Northern California, was conducted. For analysis at 12 months of age, children who were born between October 1, 1996, and December 31, 1997, and were commercially insured and covered by Medicaid were continuously enrolled; for analysis at 24 months of age, children who were born between October 1, 1996, and June 30, 1997, and were commercially insured and covered by Medicaid were continuously enrolled. The 3 measures of immunization status at 12 and 24 months of age were up-to-date status, cumulative time spent up-to-date, and the number of missed opportunity visits. RESULTS: At both HMOs, children who received IPV were as likely to be up to date at 12 months as were children who received oral poliovirus vaccine (OPV), whereas at Group Health, children who received IPV were slightly more likely to be up to date at 24 months (relative risk: 1.12; 95% confidence interval [CI]: 1.05, 1.19). These findings were consistent for children who were covered by Medicaid. At Kaiser Permanente, children who received IPV spent ~3 fewer days up to date in the first year of life, but this difference did not persist at 2 years of age. At Group Health, children who received IPV were no different from those who received OPV in terms of days spent up to date by 1 or 2 years of age. At Group Health, children who received IPV were less likely to have a missed opportunity by 12 months old (odds ratio [OR] 0.46; 95% CI: 0.31, 0.70), but this finding did not persist at 24 months of age. At Kaiser Permanente, children who received IPV were more likely to have a missed opportunity by 12 months (OR 2.06; 95% CI: 1.84, 2.30), and 24 months of age (OR 1.50; 95% CI: 1.36, 1.67). CONCLUSIONS: The changeover from an all-OPV schedule to one containing IPV had little if any negative impact on vaccine coverage. Use of IPV was associated with a small increase in the likelihood of being up to date at 2 years of age at one of the HMOs and conversely was associated with a small increase in the likelihood of having a missed-opportunity visit in the other HMO.polio, poliomyelitis, vaccination, immunization coverage.

Variation in clinician recommendations for multiple injections during adoption of inactivated polio vaccine.

OBJECTIVES: To describe variation in clinician recommendations for multiple injections during the adoption of inactivated poliovirus vaccine (IPV) in 2 large health maintenance organizations (HMOs), and to test the hypothesis that variation in recommendations would be associated with variation in immunization coverage rates. DESIGN: Cross-sectional study based on a survey of clinician practices 1 year after IPV was recommended and computerized immunization data from these clinicians' patients. STUDY SETTINGS: Two large West Coast HMOs: Kaiser Permanente in Northern California and Group Health Cooperative of Puget Sound. OUTCOME MEASURES: Immunization status of 8-month-olds and 24-month-olds cared for by the clinicians during the study. RESULTS: More clinicians at Group Health (82%), where a central guideline was issued, had adopted the IPV/oral poliovirus vaccine (OPV) sequential schedule than at Kaiser (65%), where no central guideline was issued. Clinicians at both HMOs said that if multiple injections fell due at a visit and they elected to defer some vaccines, they would be most likely to defer the hepatitis B vaccine (HBV) for infants (40%). At Kaiser, IPV users were more likely than OPV users to recommend the first HBV at birth (64% vs 28%) or if they did not, to defer the third HBV to 8 months or later (62% vs 39%). In multivariate analyses, patients whose clinicians used IPV were as likely to be fully immunized at 8 months old as those whose clinicians used all OPV. At Kaiser, where there was variability in the maximum number of injections clinicians recommended at infant visits, providers who routinely recommended 3 or 4 injections at a visit had similar immunization coverage rates as those who recommended 1 or 2. At both HMOs, clinicians who strongly recommended all possible injections at a visit had higher immunization coverage rates at 8 months than those who offered parents the choice of deferring some vaccines to a subsequent visit (at Kaiser, odds ratio [OR]: 1.2; 95% confidence interval [CI]: 1.0-1.5; at Group Health, OR: 1.8; 95% CI: 1.1-2.8). CONCLUSIONS: Neither IPV adoption nor the use of multiple injections at infant visits were associated with reductions in immunization coverage. However, at the HMO without centralized immunization guidelines, IPV adoption was associated with changes in the timing of the first and third HBV. Clinical policymakers should continue to monitor practice variation as future vaccines are added to the infant immunization schedule.

PrePare: a program of enhanced prenatal services within health-maintenance organization settings.

This paper presents the conceptual framework and implementation strategies of a relationship-focused behavioral intervention for pregnant women and their families. The program, PrePare ('Prenatal Parenting'), was designed as a prenatal precursor to the pediatric health care model, Healthy Steps. PrePare includes preventive intervention elements that address parents' universal concerns about pregnancy and parenthood, as well as specific activities to support optimum pregnancy health and reduce high-risk behaviors. As described here, the program is embedded within a large not-for-profit health-maintenance organization (HMO). Delivery of the prenatal component is carried out by Healthy Steps interventionists through three home visits and telephone follow-up during mothers' second and third trimesters of pregnancy. An evaluation of program outcomes is underway. The design compares three groups of families, those who receive PrePare followed by Healthy Steps, Healthy Steps alone and a usual HMO-practice comparison. It is hypothesized that initiating expanded services during the prenatal period will lead to increases in reported patient satisfaction, provider satisfaction and organizational efficiency within the health care delivery system.