Aligned or misaligned: Are public funding models for speech-language pathology reflecting recommended evidence? An exploratory survey of Australian speech-language pathologists

Government subsidised funding arrangements serve as an essential medium for families to access private speech-language pathology (SLP) services in Australia. This study aimed to investigate whether, from a provider perspective, contemporary public funding models (PFMs) align with best-available scientific evidence for management of children and young persons with swallowing and communication disorders within Australian private-practice settings. This exploratory study was distributed to paediatric speech-language pathologists throughout Australia via an online survey. A total of 121 valid surveys were completed by Australian speech-language pathologists with divergent career experiences. In comparing three familiar PFMs using mixed effects logistic regression models to estimate odds ratios, results indicated that perceived congruence with recommended scientific evidence for SLP management varied across PFMs: the odds of failing to align with scientific evidence was 4.92 times higher for Medicare's Chronic Disease Management Plan (MBS_CDMP) than for the National Disability Insurance Scheme; and 7.40 times higher in comparison to Medicare's Helping Children with Autism initiative. This study is the first to report on (in)congruence between PFMs that provide access to independent Australian SLP services for children and young persons and best available scientific evidence to inform clinical practice. Participants identified that: (a) four out of seven contemporary PFMs were unfamiliar to speech-language pathologists; and (b) MBS_CDMP initiative failed to align with the evidence-base for best scientific SLP management.

POS0656 FRAILTY AND RISK OF ADVERSE OUTCOMES IN BIOLOGIC OR TARGETED-SYNTHETIC DMARD TREATED PATIENTS WITH RHEUMATOID ARTHRITIS

Background

Recently, it has been recognized that frailty and pre-frailty are common in patients with rheumatoid arthritis (RA) [1]. Whether frailty status portends an increased risk of adverse outcomes in patients with RA on biologic or targeted synthetic disease modifying anti-rheumatic drugs (b- or tsDMARDs) remains unknown.

Objectives

To evaluate the association between frailty and adverse outcomes in patients with RA exposed to b- or tsDMARDs.

Methods

Using the IBM/Watson MarketScan Commercial Claims and Encounters Databases, we identified all patients with RA who filled new prescriptions (or received infusions) for TNFα antagonists (TNFi), non-TNFi biologics (rituximab, abatacept, tocilizumab) or Janus Kinase inhibitors (JAKi) between 2008-2019. We used a 1-year lookback period without the use of these drugs to identify new users. The date of the first prescription within these three drug categories was the index date. Patients’ frailty risk score was calculated using the Claims-Based Frailty Index (CFI) [2], which estimates a deficit-accumulation frailty index using International Classification of Diseases codes, Current Procedural Terminology codes, and Healthcare Common Procedure Coding System codes in administrative claims data in the 1-year baseline period. The index ranges from 0 (not at all frail) to 1 (severely frail). The primary outcome was time to serious infections (those requiring hospitalization); secondary outcomes: any infection (outpatient or inpatient encounters) and all-cause hospitalizations.

Patients were followed until 1) outcome occurrence; 2) disenrollment; 3) >90 days elapsed (or >180 days for rituximab) without further fills of the first drug categories; 4) they filled/received infusions of b-/tsDMARDs from a different drug category; or 5) 2 years after index. Cox proportional hazards adjusting for demographics, calendar year, serious and/or opportunistic infections in the 12-months prior to index were used to estimate the adjusted hazard ratios (aHR) and 95% confidence intervals (CIs) for each outcome. In separate model, we additionally adjusted for comorbidity burden, and health care utilization (HCU).

Results

A total of 62,246 patients with RA met our inclusion criteria of whom 50,910 (82%) started TNFi as their first biologic, 9525 (15%) non-TNFi biologics, and 1811 (3%) JAKi. Among these, 3928 (6%) were considered frail. In multivariable analyses, frail patients had higher risk of serious infections compared to non-frail patients (aHR 2.37, 95% CI 2.05-2.74) which decreased to aHR 1.34, 95% CI 1.13-1.58 (Table 1) after adjusting for comorbidity burden and the HCU. Similarly, frailty was associated with increased risk of any infection (aHR 1.18, 95% CI 1.11-1.25), and all-cause hospitalizations (aHR 1.34, 95% CI 1.21-1.49) relative to non-frail individuals.

Table 1.

Multivariable models evaluating the association between frailty status and inpatient infections as the outcome

Variable#Hazard Ratio (95% Confidence Interval)@Hazard Ratio (95% Confidence Interval)Frail2.37 (2.05, 2.74)1.34 (1.13, 1.58)

#Model adjusts for age, sex, major infection requiring inpatient admission in 12 months prior, concomitant baseline drugs such as csDMARDs, glucocorticoids, NSAIDs and opioids

@Model additionally adjusts for Chalrson comorbidy score and healthcare utilization

Conclusion

Frailty is an important predictor for the risk of adverse outcomes among patients with RA treated with b- or tsDMARDs. Our findings underscore the need for considering this parameter in patient evaluations (even among younger patients) in the clinic.

References

[1]Salaffi F et al: Prevalence of frailty and its associated factors in patients with rheumatoid arthritis: a cross-sectional analysis. Clin Rheumatol 2019

[2]Kim DH et al. Validation of a Claims-Based Frailty Index Against Physical Performance and Adverse Health Outcomes in the Health and Retirement Study. J Gerontol A Biol Sci Med Sci 2019

Acknowledgements

I have no acknowledgements to declare.

Disclosure of Interests

None declared

Abstract P5-09-06: Underdiagnosis of HBOC in breast cancer patients: Are genetic testing guidelines a tool or an obstacle?

Background: Pathogenic genetic variants are estimated to occur in 10-15% of all breast cancer patients, with BRCA 1/2 accounting for 40-50% of pathogenic/likely pathogenic (P/LP) variants. However, it is estimated that <30% of breast cancer patients harboring a BRCA 1/2 variant have been identified, with the percentage being much less for ˜20 other breast cancer associated genes. Reasons for this are multifactorial and include complicated and restrictive testing guidelines developed at a time when the cost of testing was high and guidelines for management were limited. Today, cost has plummeted and there are definitive management guidelines for a broader range of genes. We created a community based Registry to determine the incidence of P/LP variants in breast cancer patients who meet and who do not meet the NCCN 2017 genetic testing criteria.

Methods: An IRB-approved multicenter prospective registry was initiated with 20 community and academic sites experienced incancer genetic testing and counseling.

Eligibility criteria included patients with a breast cancer diagnosis who had not been previously tested. Consecutive patients aged 18-90 were consented and underwent an 80 gene panel test (Invitae –Multi-Cancer Panel). The non-inferiority study was powered to detect a difference in P/LP variant rate of 4 percentage points with statistical significance (p<0.05, Fisher's exact test).

HIPAA compliant electronic case report forms collected information on patient diagnosis, test results, and physician recommendations made after test results were received.

Results: Over 1000 patients were enrolled and data from 910 subjects analyzed to date. 50.4% met NCCN criteria and 49.5% did not. Median age for the enrolled patients is 60.5 and ranged from 22-93. 56.0% of patients were recently diagnosed with breast cancer. 10.9% of patients had a history of a prior non breast cancer. Overall, 8.9% of patients had a pathogenicvariant. 9.6% of patients who met NCCN criteria with test results had a P/LP variant. 8.2% of patients who did not meet criteria had a P/LP variant. The difference of positive cases among the two groups is not statistically significant (P = 0.49)

4.9% of patients had pathogenic variants if only an 11 gene standard breast cancer panel was considered.

The spectrum of mutated genes varied between the two groups, with some overlap.

Conclusions:

There was no statistically significant difference in the number of pathogenic/likely pathogenic variants between those patients who met and those who did not meet NCCN guidelines. Expanded panel testing yields more medically actionable P/LP variants than testing BRCA 1/2 alone or breast cancer panels with 11 genes. This study demonstrates that there will be a significant number of patients with P/LP variants are missed if NCCN guidelines are required for genetic testing. Current NCCN guidelines for the genetic testing of breast cancer patients are an obstacle to identifying patients with P/LP variants and should be removed.

Universal BC Genetic Testing RegistryNCCN Criteria (910 patients analyzed)#/% who have P/LP variants#/% who do not have P/LP variantsPatients who meet guidelines44/459 (9.6%)415/459 (90.4%)Patients who do not meet guidelines37/451 (8.2%)414/451 (91.8%)

Citation Format: Beitsch P, Whitworth P, Baron P, Rosen B, Compagnoni G, Simmons R, Smith LA, Holmes D, Brown E, Gold L, Clark P, Coomer C, Grady I, Barbosa K, Riley L, Kinney M, Lyons S, MacDonald H, Kahn S, Ruiz A, Patel R, Curcio L, Esplin E, Yang S. Underdiagnosis of HBOC in breast cancer patients: Are genetic testing guidelines a tool or an obstacle? [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-09-06.

Abstract P5-09-03: Expanded panel testing superior to BRCA1/2 and breast cancer panel in patients with breast cancer

Background: The testing of hereditary breast and ovarian cancer (HBOC) patients for BRCA1/2 only was established years ago to identify patients with clinically actionable variants and limit the economic burden. However, the cost of genetic testing has plummeted, and the number of breast cancer-risk genes with management guidelines has expanded. We created a community-based registry to test all breast cancer patients. A primary objective of this registry included accruing and comparing patients who did and did not meet NCCN guidelines and determining if providing all breast cancer patients with comprehensive multi-gene panel testing yields additional clinical value than testing BRCA1/2 alone.

Methods: An IRB-approved multicenter prospective registry was initiated with 20 community-based and academic breast sites, selected to insure geographic and ethnic diversity. Consecutive patients ages 18-90 with current or prior breast cancer were offered testing with an 80-gene panel (Invitae, San Francisco, CA). HIPAA-compliant case report forms collected patient diagnosis, test results, and physician recommendations made after test results.

Results: Over 1,000 patients were enrolled and data on 911 have been analyzed to date. Median age of patients is 60.5 (range 22 to 93). 56.0% were recently diagnosed with breast cancer. Of these patients, 50.54% met NCCN criteria, and 49.5% did not. 10.9% had history of a prior non-breast cancer. The pathogenic/likely pathogenic (P/LP) variant rate for patients on a comprehensive 80-gene panel was 8.9%. When restricted to a guidelines-based 11-gene breast cancer panel (BRCA1/2, ATM, CDH1, CHEK2, NBN, NF1, PTEN, STK11, TP53, PALB2), 4.9% had P/LP variants; when limited to BRCA1/2, 1.6% had P/LP variants. Of all patients with P/LP findings, 93% had variants in cancer-risk genes with established management recommendations (Table 1) and 80% had germline variants conferring eligibility for precision medicine-based cancer treatments, such as PARP inhibitors, through actively enrolling clinical trials.

Conclusions: This study demonstrates that comprehensive panel testing of breast cancer patients provides a higher yield of clinically actionable P/LP variants than BRCA1/2 testing alone. Limited panels may miss clinically relevant P/LP variants, leaving risk for preventable cancers undiscovered and unnecessarily restricting patients' treatment options. These results also suggest that variants in tumor suppressor genes, not previously thought related to breast cancer, may contribute to its etiology. A comprehensive panel strategy reveals untapped clinical utility and can impact breast cancer patient care by informing implementation of precision medicine treatment interventions and guiding long-term medical management and surveillance for patients and their family members.

 PatientsVariantsWith breast cancer management guidelines (including variants ATM*, BRCA1*, BRCA2*, CHEK2*, NBN*, NF1, PALB2*, TP53*)45 (56%)46 (55%)With cancer guidelines and clinical management implications (including variants BARD1*, FH, MITF, MSH6*, MUTYH*, PTCH1, RAD50*, RAD51C*, RAD51D*, RB1, RET, VHL)31 (38%)33 (39%)Evidence of actionability accruing (including variants BLM, DIS3L2, RECQL4)5 (6%)5 (6%)Totals8184*P/LP variants in these genes confer potential clinical trial eligibility, e.g. NCT02401347.

Citation Format: Beitsch P, Whitworth P, Baron P, Rosen B, Compagnoni G, Simmons R, Smith LA, Holmes D, Brown E, Gold L, Clark P, Coomer C, Grady I, Barbosa K, Riley L, Kinney M, Lyons S, MacDonald H, Kahn S, Ruiz A, Patel R, Curcio L, Esplin E, Yang S, Michalski S. Expanded panel testing superior to BRCA1/2 and breast cancer panel in patients with breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-09-03.

High prevalence of slight and mild hearing loss across mid-life: a cross-sectional national Australian study

OBJECTIVES

Although presbycusis typically becomes symptomatic only in older age, slight and mild hearing loss may be detectable well before this. We studied current prevalence and characteristics of hearing loss in Australian mid-life adults.

STUDY DESIGN

This was a population-derived national cross-sectional study nested within the Longitudinal Study of Australian Children.

METHODS

A total of 1485 parents/guardians (87.3% female) aged 30-59 years underwent air-conduction audiometry. Hearing loss was defined in three ways to maximize cross-study comparability: high Fletcher index (mean of 1, 2 and 4 kHz; primary outcome relevant to speech perception), lower frequency (mean of 1 and 2 kHz) and higher frequency (mean of 4 and 8 kHz). Multivariable logistic regression examined how losses vary by age, sex and neighbourhood disadvantage.

RESULTS

On high Fletcher index, 27.3% had bilateral and 23.8% unilateral thresholds >15 dB hearing level (HL) (slight or worse), and 4.9% had bilateral and 6.3% unilateral thresholds >25 dB HL (mild or worse). Bilateral higher frequency losses were more common than lower frequency losses for thresholds >15 dB HL (30.9% vs. 26.4%) and >25 dB HL (11.0% vs. 4.6%). Age increased the risk of bilateral speech and higher frequency losses (all P for trend < 0.05), but not lower frequency losses >25 dB HL. Although sex was not associated with speech and lower frequency losses, men were more likely to have bilateral higher frequency losses (e.g. >15 dB HL: odds ratio [OR]: 2.2; 95% confidence interval [CI]: 1.5-3.2, P < 0.001).

CONCLUSIONS

Both slight and mild hearing loss show high and rising prevalence across mid-life. This offers opportunities to prevent progression to reduce the profound later burden of age-related hearing loss.

Does a brief, behavioural intervention, delivered by paediatricians or psychologists improve sleep problems for children with ADHD? Protocol for a cluster-randomised, translational trial

INTRODUCTION

Up to 70% of children with attention-deficit/hyperactivity disorder (ADHD) experience sleep problems. We have demonstrated the efficacy of a brief behavioural intervention for children with ADHD in a large randomised controlled trial (RCT) and now aim to examine whether this intervention is effective in real-life clinical settings when delivered by paediatricians or psychologists. We will also assess the cost-effectiveness of the intervention.

METHODS AND ANALYSIS

Children aged 5-12 years with ADHD (n=320) are being recruited for this translational cluster RCT through paediatrician practices in Victoria and Queensland, Australia. Children are eligible if they meet criteria for ADHD, have a moderate/severe sleep problem and meet American Academy of Sleep Medicine criteria for either chronic insomnia disorder or delayed sleep-wake phase disorder; or are experiencing sleep-related anxiety. Clinicians are randomly allocated at the level of the paediatrician to either receive the sleep training or not. The behavioural intervention comprises 2 consultations covering sleep hygiene and standardised behavioural strategies. The primary outcome is change in the proportion of children with moderate/severe sleep problems from moderate/severe to no/mild by parent report at 3 months postintervention. Secondary outcomes include a range of child (eg, sleep severity, ADHD symptoms, quality of life, behaviour, working memory, executive functioning, learning, academic achievement) and primary caregiver (mental health, parenting, work attendance) measures. Analyses will address clustering at the level of the paediatrician using linear mixed effect models adjusting for potential a priori confounding variables.

ETHICS AND DISSEMINATION

Ethics approval has been granted. Findings will determine whether the benefits of an efficacy trial can be realised more broadly at the population level and will inform the development of clinical guidelines for managing sleep problems in this population. We will seek to publish in leading international paediatric journals, present at major conferences and through established clinician networks.

TRIAL REGISTRATION NUMBER

ISRCTN50834814, Pre-results.

Child oral health in migrant families: A cross-sectional study of caries in 1-4 year old children from migrant backgrounds residing in Melbourne, Australia

Early Childhood Caries (ECC) is the most common, preventable disease of childhood. It can affect children's health and wellbeing and children from migrant families may be at greater risk of developing ECC.

OBJECTIVE

To describe ECC in children from migrant families, and explore possible influences.

BASIC RESEARCH DESIGN

Cross-sectional analysis of caries data collected as baseline data for an oral health promotion study.

PARTICIPANTS

The analysis sample included 630 1-4 year-old children clustered within 481 Iraqi, Lebanese and Pakistani families in Melbourne, Australia.

METHOD

Child participants received a community-based visual dental examination. Parents completed a self-administered questionnaire on demographics, ethnicity, and oral health knowledge, behaviour and attitudes.

MAIN OUTCOME MEASURE

Child caries experience. Bivariate associations between oral health behaviours and ethnicity were tested for significance using chi-square. Multivariate logistic regression analyses were performed to identify associations with ECC, adjusting for demographic variables and accounting for clustering by family.

RESULTS

Overall, 34% of children in the sample experienced caries (both non-cavitated and cavitated). For all caries lesions, parent' length of residence in Australia, consumption of sweet drinks and parental education remained as independent predictors of child caries experience. Adding sugar to drinks was an additional risk factor for cavitation. Ethnicity was associated with some individual oral health behaviours suggesting cultural influences on health, however the relationship was not independent of other predictors.

CONCLUSION

Culturally competent oral health promotion interventions should aim to support migrant families with young children, and focus on reducing sweet drink consumption.

Choosing foods for infants: a qualitative study of the factors that influence mothers

BACKGROUND

Examining the experiences of parents making food choices for infants is important because ultimately this influences what infants eat. Infancy is a critical period when food preferences and eating behaviour begin to develop, shaping dietary patterns, growth and health outcomes. There is limited evidence regarding what or why foods are chosen for infants.

OBJECTIVE

To describe the experiences of mothers making food choices for their infant children.

METHODS

Semi-structured interviews with 32 Australian mothers of infants aged four to 15 months from a range of socioeconomic backgrounds. An inductive thematic analysis through a process of constant comparison was conducted on transcribed interviews.

RESULTS

Mothers described many ideas and circumstances which influenced food choices they made for infants. Themes were developed which encapsulate how the wider environment and individual circumstances combine to result in the food choices made for infants. Beliefs, values, norms and knowledge were a central influence on choices. Cost, quality and availabilities of various foods were also key factors. Related to this, and combined with inherent factors such as perishability and infant acceptability, fresh fruits and vegetables were often singled out as an easy or difficult choice. Influences of time, parents' capacities, social connections and different information sources were clearly apparent. Finally infants' own preferences and how parents helped infants with learning to eat were also key influences on food choices.

CONCLUSIONS

Choosing foods for infants is a complex social practice. An ecological framework depicting the multiple influences on what people eat and sociological theory on food choice regarding the role of 'social structure' and 'human agency' are both applicable to the process of choosing foods for infants. Equity issues may be key regarding the degree to which mothers can choose particular foods for infants (e.g. choosing foods which promote health).

An exploration of the views of Australian mothers on promoting child oral health

BACKGROUND

An important role for parents and caregivers in the prevention of dental caries in children is the early establishment of health promoting behaviours. This study aimed to examine mothers' views on barriers and facilitators to promoting child and family oral health.

METHODS

Semi-structured interviews were undertaken with a purposive sample of mothers (n = 32) of young children. Inductive thematic analysis was conducted.

RESULTS

Parental knowledge and beliefs, past experiences and child behaviour emerged as major influences on children's oral health. Child temperament and parental time pressures were identified as barriers to good oral health with various strategies reported for dealing with uncooperative children at toothbrushing time. Parental oral health knowledge and beliefs emerged as positive influences on child oral health; however, while most mothers were aware of the common causes of dental caries, very few knew of other risk factors such as bedtime feeding. Parents' own oral health experiences were also seen to positively influence child oral health, regardless of whether these were positive or negative experiences.

CONCLUSIONS

Understanding parental oral health beliefs is essential to overcoming barriers and promoting enablers for good child oral health. Improving child oral health also requires consideration of child behaviour, family influences, and increasing awareness of lesser-known influencing factors.

Exploring child dental service use among migrant families in metropolitan Melbourne, Australia

BACKGROUND

This study describes and explores factors related to dental service use among migrant children.

METHODS

A cross-sectional analysis of baseline data from Teeth Tales, an exploratory trial implementing a community based child oral health promotion intervention. The sample size and target population was 600 families with 1-4 year old children from Iraqi, Lebanese and Pakistani backgrounds residing in metropolitan Melbourne. Participants were recruited into the study using purposive and snowball sampling techniques.

RESULTS

Most (88%; 550/625) children had never visited the dentist (mean (SD) age 3.06 years (1.11)). In the fully adjusted model the variable most significantly associated with child dental visiting was parent reported 'no reason for child to visit the dentist' (OR = 0.07, p < 0.001). Of those children whose parents reported their child had no reason to visit the dentist, 22% (37/165) experienced dental caries with 8% (13/165) at the level of cavitation.

CONCLUSIONS

Dental service use by migrant preschool children was very low. The relationship between perceived dental need and dental service use is currently not aligned. One in 10 children of select migrant background had visited a dentist, which is in the context of 1 in 3 with dental caries. To improve utilization, health services should consider organizational cultural competence, outreach and increased engagement with the migrant community.

Community-based healthcare costs for children born low birthweight, preterm and/or small for gestational age: data from the Longitudinal Study of Australian Children

AIM

Children born low birthweight, preterm and/or small for gestational age (SGA) sustain substantially increased costs for hospital-based health care and additional educational support in the first few years of life. This is the first study internationally to investigate costs beyond hospital care, to community-based health care and prescription medicines across early and middle childhood with actual cost data, and to examine these costs according to the severity of perinatal risk.

METHOD

In the prospective Longitudinal Study of Australian Children, we followed two cohorts of children from age of 0 to 5 years (no increased perinatal risk, n = 3973; mild risk, n = 442; and moderate-to-high risk, n = 297), and from age of 4 to 9 years (no increased perinatal risk, n = 3629; mild risk, n = 465; and moderate-to-high risk, n = 361). Children were defined as mild risk if born 32-36 weeks, with birthweight 1500-2499 g, and/or SGA (<5-9th percentile), and moderate-to-high risk if born <32 weeks, birthweight <1500 g and/or extremely SGA (<5th percentile). Federal government expenditure (2011 $AUD) on healthcare attendances and prescription medication from birth to 9 years were calculated via data linkage to the Australian Medicare records.

RESULTS

Mean costs per child were A$362 higher (95% CI $156; 568) from 0 to 5 years and A$306 higher (95% CI $137; 475) from 4 to 9 years, for children with any compared with no increased perinatal risk (P < 0.001). At the population level, an additional A$32m was spent per year for children 0-9 years with any relative to no increased perinatal risk.

CONCLUSIONS

Perinatal risk is a major public health issue conferring considerable additional expense to community-based health care, most marked in the first year of life but persisting up to at least 10 years. Even without additionally considering burden, these findings add to the urgency of identifying effective mechanisms to reduce perinatal risk across its full spectrum.

Methodology for the evaluation of the Stephanie Alexander Kitchen Garden program

ISSUES ADDRESSED

Community and school cooking and gardening programs have recently increased internationally. However, despite promising indications, there is limited evidence of their effectiveness. This paper presents the evaluation framework and methods negotiated and developed to meet the information needs of all stakeholders for the Stephanie Alexander Kitchen Garden (SAKG) program, a combined cooking and gardening program implemented in selectively funded primary schools across Australia.

METHODS

The evaluation used multiple aligned theoretical frameworks and models, including a public health ecological approach, principles of effective health promotion and models of experiential learning. The evaluation is a non-randomised comparison of six schools receiving the program (intervention) and six comparison schools (all government-funded primary schools) in urban and rural areas of Victoria, Australia. A mixed-methods approach was used, relying on qualitative measures to understand changes in school cultures and the experiential impacts on children, families, teachers, parents and volunteers, and quantitative measures at baseline and 1 year follow up to provide supporting information regarding patterns of change.

RESULTS

The evaluation study design addressed the limitations of many existing evaluation studies of cooking or garden programs. The multistrand approach to the mixed methodology maintained the rigour of the respective methods and provided an opportunity to explore complexity in the findings. Limited sensitivity of some of the quantitative measures was identified, as well as the potential for bias in the coding of the open-ended questions.

CONCLUSION

The SAKG evaluation methodology will address the need for appropriate evaluation approaches for school-based kitchen garden programs. It demonstrates the feasibility of a meaningful, comprehensive evaluation of school-based programs and also demonstrates the central role qualitative methods can have in a mixed-method evaluation. So what? This paper contributes to debate about appropriate evaluation approaches to meet the information needs of all stakeholders and will support the sharing of measures and potential comparisons between program outcomes for comparable population groups and settings.

Primary healthcare costs associated with sleep problems up to age 7 years: Australian population-based study

OBJECTIVES

In Australian 0-7-year olds with and without sleep problems, to compare (1) type and costs to government of non-hospital healthcare services and prescription medication in each year of age and (2) the cumulative costs according to persistence of the sleep problem.

DESIGN

Cross-sectional and longitudinal data from a longitudinal population study.

SETTING

Data from two cohorts participating in the first two waves of the nationally representative Longitudinal Study of Australian Children.

PARTICIPANTS

Baby cohort at ages 0-1 and 2-3 (n=5107, 4606) and Kindergarten cohort at ages 4-5 and 6-7 (n=4983, 4460).

MEASUREMENTS

Federal Government expenditure on healthcare attendances and prescription medication from birth to 8 years, calculated via linkage to Australian Medicare data, were compared according to parent report of child sleep problems at each of the surveys.

RESULTS

At both waves and in both cohorts, over 92% of children had both sleep and Medicare data. The average additional healthcare costs for children with sleep problems ranged from $141 (age 5) to $43 (age 7), falling to $98 (age 5) to $18 (age 7) per child per annum once family socioeconomic position, child gender, global health and special healthcare needs were taken into account. This equates to an estimated additional $27.5 million (95% CI $9.2 to $46.8 million) cost to the Australian federal government every year for all children aged between 0 and 7 years. In both cohorts, costs were higher for persistent than transient sleep problems.

CONCLUSIONS

Higher healthcare costs were sustained by infants and children with sleep problems. This supports ongoing economic evaluations of early prevention and intervention services for sleep problems considering impacts not only on the child and family but also on the healthcare system.

Effects of continuity of care by a primary midwife (caseload midwifery) on caesarean section rates in women of low obstetric risk: the COSMOS randomised controlled trial

OBJECTIVE

To determine whether primary midwife care (caseload midwifery) decreases the caesarean section rate compared with standard maternity care.

DESIGN

Randomised controlled trial.

SETTING

Tertiary-care women's hospital in Melbourne, Australia.

POPULATION

A total of 2314 low-risk pregnant women.

METHODS

Women randomised to caseload received antenatal, intrapartum and postpartum care from a primary midwife with some care by 'back-up' midwives. Women randomised to standard care received either midwifery or obstetric-trainee care with varying levels of continuity, or community-based general practitioner care.

MAIN OUTCOME MEASURES

PRIMARY OUTCOME

caesarean birth. Secondary outcomes included instrumental vaginal births, analgesia, perineal trauma, induction of labour, infant admission to special/neonatal intensive care, gestational age, Apgar scores and birthweight.

RESULTS

In total 2314 women were randomised-1156 to caseload and 1158 to standard care. Women allocated to caseload were less likely to have a caesarean section (19.4% versus 24.9%; risk ratio [RR] 0.78; 95% CI 0.67-0.91; P = 0.001); more likely to have a spontaneous vaginal birth (63.0% versus 55.7%; RR 1.13; 95% CI 1.06-1.21; P < 0.001); less likely to have epidural analgesia (30.5% versus 34.6%; RR 0.88; 95% CI 0.79-0.996; P = 0.04) and less likely to have an episiotomy (23.1% versus 29.4%; RR 0.79; 95% CI 0.67-0.92; P = 0.003). Infants of women allocated to caseload were less likely to be admitted to special or neonatal intensive care (4.0% versus 6.4%; RR 0.63; 95% CI 0.44-0.90; P = 0.01). No infant outcomes favoured standard care.

CONCLUSION

In settings with a relatively high baseline caesarean section rate, caseload midwifery for women at low obstetric risk in early pregnancy shows promise for reducing caesarean births.

Prevalence of multiple sclerosis in Buenos Aires, Argentina using the capture-recapture method

BACKGROUND

Scarce data exist about multiple sclerosis (MS) prevalence in South America. The objective of the study is to determine the prevalence of MS in a high populated area from Argentina (Greater Buenos Aires Metropolitan area) using the capture-recapture methodology.

METHODS

Greater Buenos Aires is the generic denomination that refers to the megalopolis comprised by the autonomous city of Buenos Aires and the surrounding conurbation of the province of Buenos Aires. The study was carried out taking July 1996 as the prevalence month. We used capture-recapture method to estimate the prevalence of MS cross matching registries from four MS Centers.

RESULTS

A total of 803 registries were obtained from the four lists. Log-linear model for capture-recapture method was used to analyze the data. The population of the area based on the 1990 census was 12,594,974; the number of MS cases estimated amongst sources interactions were between 1833 and 2359; the prevalence estimated ranged from 14 to 19.8 cases per 100,000 inhabitants.

CONCLUSIONS

This is the first study to provide epidemiological data on the prevalence of MS in a large population in Argentina (Greater Buenos Aires Metropolitan area). Further epidemiological studies will clarify the true prevalence of MS in South America.

Site of the ischemic penumbra as a predictor of potential for recovery of functions

BACKGROUND AND PURPOSE

Diffusion-perfusion mismatch has been used to estimate salvageable tissue and predict potential for recovery in acute stroke. Location of the salvageable tissue may be as important as volume or percentage in predicting potential for recovery of specific functions. Impaired naming, a common and disabling deficit after left hemisphere stroke, is often associated with tissue dysfunction of left Brodmann area (BA) 37, posterior inferior temporal cortex. We tested the hypothesis that the presence of diffusion-perfusion mismatch within left BA 37 predicts probability and extent of short-term improvement of naming.

METHODS

One hundred five patients with acute left hemisphere ischemic stroke had diffusion-weighted imaging, perfusion-weighted imaging, a test of picture naming, and other language tests at admission and 2 to 4 days later. Linear regression was used to determine whether diffusion-perfusion mismatch in any BA in language cortex, total volume of mismatch, or diffusion or perfusion abnormality predicted degree of improvement in naming by days 3 to 5.

RESULTS

The presence of >20% diffusion-perfusion mismatch in left BA 37 and total volumes of diffusion and perfusion abnormality at day 1 each independently predicted degree of improvement in naming. Mismatch in this area did not predict the degree of improvement in other language tests or the NIH Stroke Scale in this study.

CONCLUSIONS/RELEVANCE

Diffusion-perfusion mismatch in left Brodmann area 37 was strongly associated with acute improvement in naming, independently of volume or percentage of total mismatch or diffusion or perfusion abnormality. These data indicate that mismatch in a particular area is a marker of salvageable tissue and an important predictor of potential for recovery of functions that depend on that area. Location of mismatch before treatment may help to predict potential benefits of reperfusion.

Argentine Patagonia: prevalence and clinical features of multiple sclerosis

There are few studies reporting multiple sclerosis prevalence rates in the Buenos Aires region, Argentina (latitude 34°S) (between 12–18.5/100 000 inhabitants), and no studies have been performed in the larger region between parallels 36° and 55°S. The aim of this study is to determine the prevalence rates and clinical features of multiple sclerosis in residents of the Argentine Patagonia. Four cities from the region were selected for this study, giving a sample population of 417 666 inhabitants (~24% of the total Patagonia population). 1st March 2002 was determined as prevalence day. Patients were ascertained using multiple case-finding methods. The point prevalence rate was 17.2/100 000 (17.2 age-adjusted to the world population). Prevalence rates were higher for women than for men, 22.1 versus 12.2/100 000 inhabitants (21.4 versus 12.7 sex-adjusted to the world population). The study population was mainly of European descent and mestizoes. Clinical features were similar to those reported in other countries. This study shows that Argentine Patagonia is a medium-risk area with no south–north gradient between parallels 55° and 36°S. The Patagonia population shows recent internal migration that makes it difficult to determine whether the exposure to potential risk factors has been long enough to modify the disease incidence.

Theoretical principles of in vitro selection using combinatorial nucleic acid libraries

A new paradigm for drug discovery and biological research has developed from technologies that integrate combinatorial chemistry with rounds of selection and amplification, a technique called in vitro selection or systematic evolution of ligands by exponential enrichment (SELEX). This overview unit discusses nucleic acid libraries that can be used, affinity probability distributions, an equilibrium model for SELEX, and optimal conditions including concentrations and signal-to-noise ratios.

Outcome data from the LEAP (Live, Eat and Play) trial: a randomized controlled trial of a primary care intervention for childhood overweight/mild obesity

OBJECTIVES

To reduce gain in body mass index (BMI) in overweight/mildly obese children in the primary care setting.

DESIGN

Randomized controlled trial (RCT) nested within a baseline cross-sectional BMI survey.

SETTING

Twenty nine general practices, Melbourne, Australia.

PARTICIPANTS

(1) BMI survey: 2112 children visiting their general practitioner (GP) April-December 2002; (2) RCT: individually randomized overweight/mildly obese (BMI z-score <3.0) children aged 5 years 0 months-9 years 11 months (82 intervention, 81 control).

INTERVENTION

Four standard GP consultations over 12 weeks, targeting change in nutrition, physical activity and sedentary behaviour, supported by purpose-designed family materials.

MAIN OUTCOME MEASURES

Primary: BMI at 9 and 15 months post-randomization. Secondary: Parent-reported child nutrition, physical activity and health status; child-reported health status, body satisfaction and appearance/self-worth.

RESULTS

Attrition was 10%. The adjusted mean difference (intervention-control) in BMI was -0.2 kg/m(2) (95% CI: -0.6 to 0.1; P=0.25) at 9 months and -0.0 kg/m(2) (95% CI: -0.5 to 0.5; P=1.00) at 15 months. There was a relative improvement in nutrition scores in the intervention arm at both 9 and 15 months. There was weak evidence of an increase in daily physical activity in the intervention arm. Health status and body image were similar in the trial arms.

CONCLUSIONS

This intervention did not result in a sustained BMI reduction, despite the improvement in parent-reported nutrition. Brief individualized solution-focused approaches may not be an effective approach to childhood overweight. Alternatively, this intervention may not have been intensive enough or the GP training may have been insufficient; however, increasing either would have significant cost and resource implications at a population level.

Impaired neurovascular coupling by transhemispheric diaschisis in rat cerebral cortex

In acute brain disorders, elimination of the excitatory output from an injured brain region reduces activity in connecting brain regions remote from the lesion site (i.e., diaschisis). The authors examined the effect of functional ablation of the left cerebral cortex by cortical spreading depression (CSD) or topical application of tetrodotoxin on single cell spiking activity, baseline CBF, and neurovascular coupling in the right rat sensory cortex. CSD or tetrodotoxin in left cortex reduced the right cortical spontaneous spike rate by 36% and 45%, respectively. Baseline CBF in the right cortex was unaffected by a left-sided CSD, but decreased by 12% for left cortical application of tetrodotoxin. This suggested dissociation between spontaneous spiking activity and basal CBF. Left in-fraorbital nerve stimulation evoked local field potentials in right cerebral cortex that were reduced in amplitude by 19% for left CSD and by 23% for left tetrodotoxin application. The corresponding declines in the evoked CBF responses were 42% for CSD and 23% for tetrodotoxin. Vascular reactivity to adenosine remained unchanged in right cortex. Thus, transhemispheric diaschisis produced a pronounced decrease in the spontaneous spike rate accompanied by no reduction or a small reduction in basal CBF, and an attenuation in amplitudes of evoked synaptic responses and corresponding rises in CBF. The findings suggest that disturbed neurovascular coupling may contribute to the disturbance in brain function in acute transhemispheric diaschisis.

Context sensitivity of activity-dependent increases in cerebral blood flow

Functional neuroimaging in humans is used widely to study brain function in relation to human disease and cognition. The neural basis of neuroimaging signals is probably synaptic activity, but the effect of context, defined as the interaction between synaptic inhibition, excitation, and the electroresponsive properties of the targeted neurons, is not well understood. We examined here the effect of interaction of synaptic excitation and net inhibition on the relationship between electrical activity and vascular signals in the cerebellar cortex. We show that stimulation of the net inhibitory parallel fibers simultaneously with stimulation of the excitatory climbing fibers leads to a further rise in total local field potentials (LFP) and cerebral blood flow (CBF) amplitudes, not a decrease, as predicted from theoretical studies. However, the combined stimulation of the parallel and climbing fiber systems produced changes in CBF and LFP that were smaller than their algebraic sum evoked by separate stimulation of either system. This finding was independent of the starting condition, i.e., whether inhibition was superimposed on a state of excitation or vice versa. The attenuation of the increases in LFP and CBF amplitudes was similar, suggesting that synaptic activity and CBF were coupled under these conditions. The result might be explained by a relative neuronal refractoriness that relates to the intrinsic membrane properties of Purkinje cells, which determine the recovery time of these cells. Our work implies that neuronal and vascular signals are context-sensitive and that their amplitudes are modulated by the electroresponsive properties of the targeted neurons.

Neuronal deactivation explains decreased cerebellar blood flow in response to focal cerebral ischemia or suppressed neocortical function

Functional neuroimaging in humans with acute brain damage often reveals decreases in blood flow and metabolism in areas unaffected by the lesion. This phenomenon, termed diaschisis, is presumably caused by disruption of afferent excitatory input from the lesioned area to other brain regions. By characterizing its neurophysiological basis, we used cerebellar diaschisis to study the relationship between electrical activity and blood flow during decreased neuronal activity. Here we show that focal cerebral ischemia in rats causes diaschisis in the cerebellar cortex characterized by pronounced decreases in Purkinje cell spiking activity and small decreases in cerebellar blood flow. The findings were explained by decreased excitatory input to the cerebellar cortex, i.e., deactivation, as cerebellar neuronal excitability and vascular reactivity were preserved. Functional ablation of the cerebral cortex by either spreading depression or tetrodotoxin reproduced the changes in cerebellar function with complete recovery of Purkinje cell activity and cerebellar blood flow concomitant with recovery of neocortical function. Decreases of activity involving the contralateral frontal cortex produced the largest decrease in cerebellar electrical activity and blood flow. Our data suggest that deactivation explains the decreases in blood flow and metabolism in cerebellar diaschisis observed in human neuroimaging studies. Decreases in spiking activity were 3-7 times larger than the respective decreases in flow. Therefore, under pathological conditions, neuroimaging methods based on hemodynamic signals may only show small changes, although the underlying decrease in neuronal activity is much larger.

Systematic review of randomised controlled trials of sildenafil (Viagra) in the treatment of male erectile dysfunction

BACKGROUND

Sildenafil (Viagra), a new oral drug for the treatment of erectile dysfunction, was licensed for use across Europe in 1998.

AIM

To examine the effectiveness and safety of sildenafil as an oral treatment for erectile dysfunction.

DESIGN OF STUDY

Systematic review and meta-analysis.

SETTING

All published or unpublished randomised controlled trials comparing sildenafil with a placebo or alternative therapies.

METHOD

Published studies were sought by computerised searches of electronic databases using the keywords 'sildenafil' and 'Viagra'. A hand search was also done of the British Medical Journal, Lancet, Journal of the American Medical Association, New England Journal of Medicine, British journal of General Practice, Drug, Inpharma and Scrip. An assessment of quality of all identified studies and data extraction was undertaken independently by two researchers. Results were combined in a meta-analysis where appropriate, using RevMan version 3.

RESULTS

Twenty-one trials were identified. All trials showed a statistically significant improvement in erectile or sexual function in patients using sildenafil compared with a placebo. A meta-analysis of 16 trials reporting a global efficacy response showed that men were 3.57 (95% CI = 2.93-4.43) times as likely to have improved erections on sildenafil compared with those on a placebo. The number needed to treat to have one man with improved erections was two. The drug has a relatively safe side-effect profile.

CONCLUSIONS

Available research shows that sildenafil is an effective treatment for male erectile dysfunction. Many trial participants had some baseline erectile function and it is probable that in clinical practice, where the erectile function tends to be more impaired, the number needed to treat may be higher.

No Evidence for Early Decrease in Blood Oxygenation in Rat Whisker Cortex in Response to Functional Activation

Using optical methods through a closed cranial window over the rat primary sensory cortex in chloralose/urethane-anesthetized rats we evaluated the time course of oxygen delivery and consumption in response to a physiological stimulus (whisker deflection). Independent methodological approaches (optical imaging spectroscopy, single fiber spectroscopy, oxygen-dependent phosphorescence quenching) were applied to different modes of whisker deflection (single whisker, full whisker pad). Spectroscopic data were evaluated using different algorithms (constant pathlength, differential pathlength correction). We found that whisker deflection is accompanied by a significant increase of oxygenated hemoglobin (oxy-Hb), followed by an undershoot. An early increase in deoxygenated hemoglobin (deoxy-Hb) proceeded hyperoxygenation when spectroscopic data were analyzed by constant pathlength analysis. However, correcting for the wavelength dependence of photon pathlength in brain tissue (differential pathlength correction) completely eliminated the increase in deoxy-Hb. Oxygen-dependent phosphorescence quenching did not reproducibly detect early deoxygenation. Together with recent fMRI data, our results argue against significant early deoxygenation as a universal phenomenon in functionally activated mammalian brain. Interpreted with a diffusion-limited model of oxygen delivery to brain tissue our results are compatible with coupling between neuronal activity and cerebral blood flow throughout stimulation, as postulated 110 years ago by C. Roy and C. Sherrington (1890, J. Physiol. 11:85--108).

The effectiveness of the levonorgestrel-releasing intrauterine system in menorrhagia: a systematic review

OBJECTIVE

To determine whether the levonorgestrel-releasing intrauterine device (LNG-IUS), licensed at present for contraceptive use, may reduce menstrual blood loss with few side effects. If effective, surgery could be avoided with consequent resource savings.

METHODS

A systematic review addressing the effectiveness and cost effectiveness of the LNG-IUS for menorrhagia was undertaken.

RESULTS

Five controlled trials and five case series were found which measured menstrual blood loss. Nine studies recorded statistically significant average menstrual blood loss reductions with LNG-IUS (range 74%-97%). Another showed reduction in menstrual disturbance score. The LNG-IUS was more effective than tranexamic acid, but slightly less effective than endometrial resection at reducing menstrual blood loss. In one study, 64% of women cancelled surgery at six months, compared with 14% of control group women. In another, 82% were taken off surgical waiting lists at one year. No cost effectiveness studies were found.

DISCUSSION

Small studies of moderate quality indicate the LNG-IUS is an effective treatment for menorrhagia. Costs may be less than for tranexamic acid in primary and secondary care. Although its use may reduce surgical waiting lists, cost effectiveness assessment requires longer follow up.

CONCLUSION

Effectiveness and cost effectiveness relative to other treatments and the effect on surgical waiting lists can only be established in larger trials measuring patient-centred outcomes in women with menorrhagia.

Physical model for the spectroscopic analysis of cortical intrinsic optical signals

We used Monte Carlo simulations and the diffusion approximation to estimate correction terms for the analysis of reflectance spectra of cortical intrinsic optical signals. These corrections depend on scattering and absorption properties, i.e. they are dependent on assumptions on the tissue blood content and oxygen saturation. The analysis was applied to reflectance spectra acquired during whisker barrel stimulation in the rat where attenuation spectra were converted to changes in oxygenated and deoxygenated haemoglobin concentration. The description of the experimental data as judged by the residual and sensitivity to variations of wavelength was considerably improved when the correction terms were included. Inclusion of the correction does have a considerable impact on the time course of deoxyhaemoglobin concentration changes. In contrast to the calculation without correction terms, there is no indication for an early increase in deoxyhaemoglobin ('early dip'). This finding might further current interpretation of the coupling between neuronal activation and oxygen extraction and supply.

Mater, a maternal effect gene required for early embryonic development in mice

Maternal effect genes produce mRNA or proteins that accumulate in the egg during oogenesis. We show here that Mater, a mouse oocyte protein dependent on the maternal genome, is essential for embryonic development beyond the two-cell stage. Females lacking the maternal effect gene Mater are sterile. Null males are fertile.

Interactions of Escherichia coli RNA with bacteriophage MS2 coat protein: genomic SELEX

Genomic SELEX is a method for studying the network of nucleic acid-protein interactions within any organism. Here we report the discovery of several interesting and potentially biologically important interactions using genomic SELEX. We have found that bacteriophage MS2 coat protein binds several Escherichia coli mRNA fragments more tightly than it binds the natural, well-studied, phage mRNA site. MS2 coat protein binds mRNA fragments from rffG (involved in formation of lipopolysaccharide in the bacterial outer membrane), ebgR (lactose utilization repressor), as well as from several other genes. Genomic SELEX may yield experimentally induced artifacts, such as molecules in which the fixed sequences participate in binding. We describe several methods (annealing of oligonucleotides complementary to fixed sequences or switching fixed sequences) to eliminate some, or almost all, of these artifacts. Such methods may be useful tools for both randomized sequence SELEX and genomic SELEX.

Preference measurement using conjoint methods: an empirical investigation of reliability

The application of conjoint measurement to the field of health economics is relatively new, although there is growing interest and there have been a number of studies undertaken recently. Wider acceptance of the technique requires methodological issues concerning both reliability and validity to be addressed. This paper reports an empirical investigation of the test-retest reliability of the discrete choice conjoint measurement approach in health care. This investigation of conjoint reliability was framed using the clinical context of investigation and treatment of knee injuries. A high level of reliability at both the input data and results levels was demonstrated.

Aptamers as therapeutic and diagnostic agents

Aptamers are oligonucleotides derived from an in vitro evolution process called SELEX. Aptamers have been evolved to bind proteins which are associated with a number of disease states. Using this method, many powerful antagonists of such proteins have been found. In order for these antagonists to work in animal models of disease and in humans, it is necessary to modify the aptamers. First of all, sugar modifications of nucleoside triphosphates are necessary to render the resulting aptamers resistant to nucleases found in serum. Changing the 2'OH groups of ribose to 2'F or 2'NH2 groups yields aptamers which are long lived in blood. The relatively low molecular weight of aptamers (8000-12000) leads to rapid clearance from the blood. Aptamers can be kept in the circulation from hours to days by conjugating them to higher molecular weight vehicles. When modified, conjugated aptamers are injected into animals, they inhibit physiological functions known to be associated with their target proteins. A new approach to diagnostics is also described. Aptamer arrays on solid surfaces will become available rapidly because the SELEX protocol has been successfully automated. The use of photo-cross-linkable aptamers will allow the covalent attachment of aptamers to their cognate proteins, with very low backgrounds from other proteins in body fluids. Finally, protein staining with any reagent which distinguishes functional groups of amino acids from those of nucleic acids (and the solid support) will give a direct readout of proteins on the solid support.

The use of aptamers in large arrays for molecular diagnostics

BACKGROUND

Aptamers are single-stranded oligonucleotides derived from an in vitro evolution protocol called systematic evolution of ligands by exponential enrichment (SELEX). They bind tightly and specifically to target molecules; most aptamers to proteins bind with Kds (equilibrium dissociation constant) in the range of 1 pM to 1 nM.

METHODS AND RESULTS

The SELEX protocol has been automated; therefore, hundreds to thousands of aptamers can be made in an economically feasible fashion. Blood and urine can be analyzed on chips that capture and quantitate proteins. SELEX has been adapted to the use of 5-bromo (5-Br) and 5-iodo (5-I) deoxyuridine residues. These halogenated bases can be specifically cross-linked to proteins. Selection pressure during in vitro evolution can be applied for both binding specificity and specific photo-cross-linkability. These are sufficiently independent parameters to allow one reagent, a photo-cross-linkable aptamer, to substitute for two reagents, the capture antibody and the detection antibody, in a typical sandwich array. After a cycle of binding, washing, cross-linking, and detergent washing, proteins will be specifically and covalently linked to their cognate aptamers.

CONCLUSIONS

Because no other proteins are present on the chips, protein-specific stain will now show a meaningful array of pixels on the chip. Learning algorithms and retrospective studies should lead to a robust, simple, diagnostic chip.

Using the continuous quality improvement process to safely lower the cesarean section rate

BACKGROUND

In 1994 a five-year prospective observational study (including 38,541 singleton live-born deliveries) based on maternal and neonatal hospital administrative discharge data for DRGs 370-375 was launched at Cedars Sinai Medical Center (CSMC) in Los Angeles. In 1993 a cesarean section (C-section) reduction task force was first convened and several interventions were conducted and monitored during a two-year period. In 1995 CSMC joined the Institute for Healthcare Improvement's (IHI's) national collaborative on lowering C-section rates.

RESULTS

The first intervention involved physician education (grand rounds) and occurred during the preintervention baseline period. Providing physician-specific data had been implemented before participation in the IHI collaborative. Two other interventions were implemented before the collaborative versus 13 interventions after. The C-section rate decreased from 26.0% in the baseline period in 1993 to 20.5% in 1997, a 21.2% reduction. During the postintervention period, the C-section rate increased to 23.5%. There was no statistically or clinically significant increase in clavicular fractures, brachial plexus injuries, or cerebral hemorrhage in the four study years, compared to the baseline period.

DISCUSSION

It is possible to safely reduce C-section delivery rates. Activities are now under way to involve additional private physician leaders in the continuous quality improvement effort. Although the small increase in the C-section rate during the postintervention period may represent statistical variation, and in itself may not be clinically significant, it supports the thesis that ongoing, continuous organizational support is required to achieve and maintain gains.

Incorporation of mouse zona pellucida proteins into the envelope of Xenopus laevis oocytes

All vertebrate eggs have extracellular matrices, referred to as the zona pellucida in Mus musculus and the vitelline envelope in Xenopus laevis. The mouse zona, composed of three sulfated glycoproteins (ZP1, ZP2, ZP3), is critical for fertilization and early development, and mice lacking a zona pellucida produce no live offspring. The primary structures of mouse ZP1 (623 amino acids), ZP2 (713 amino acids) and ZP3 (424 amino acids) have been deduced from full-length cDNAs, but posttranslational modifications result in mature zona proteins with molecular masses of 200-180 kDa, 140-120 kDa, and 83 kDa, respectively. The vitelline envelope forms a similar structure around Xenopus eggs and contains three glycoproteins that are structurally related (39-48% amino acid similarity) to the three mouse zona proteins. To investigate whether the structural semblances are sufficient to allow incorporation of the mouse zona proteins into the Xenopus vitelline envelope, capped synthetic mRNAs encoding ZP1, ZP2, and ZP3 proteins were injected into the cytoplasm of stage VI Xenopus oocytes. After 20 h of incubation the oocytes were harvested, and posttranslationally modified zona proteins were detected with monoclonal antibodies specific to mouse ZP1, ZP2, and ZP3. The oocytes were imaged with confocal microscopy to detect individual zona proteins in the extracellular matrix of the oocytes, and this localization was confirmed biochemically. Thus the mouse zona proteins appear to have been sufficiently conserved through 350 million years of evolution to be incorporated into the extracellular envelope surrounding Xenopus eggs.

Perivascular nerves contribute to cortical spreading depression-associated hyperemia in rats

We investigated the contribution of perivascular nerves and neurotransmitters to cortical spreading depression (CSD)-associated hyperperfusion in the rat. Chronic transection of the nasociliary nerve (NCN, 2 wk before) decreased ipsilateral CSD-associated hyperperfusion by 23 +/- 13% (mean +/- SD; n = 5, P < 0.05), whereas acute transection of the NCN or sham surgery had no effect (n = 8). When the NCN and parasympathetic nerve fibers (PSN) were both chronically transected, CSD hyperperfusion was attenuated by 55 +/- 19% (n = 5, P < 0.05). Cerebrovascular reactivity to hypercapnia was not significantly affected. Brain topical superfusion of the muscarinic receptor antagonist atropine (10(-4) M) caused a reduction of CSD hyperperfusion by 41 +/- 13% (n = 5, P < 0.05). The competitive blockade of calcitonin gene-related peptide (CGRP) receptors by CGRP-(8-37) (5 x 10(-7) M) afforded a decrease by 49 +/- 19% (n = 5, P < 0.05), without affecting CO2 reactivity (n = 4). The combined application of both CGRP-(8-37) and atropine further attenuated CSD hyperperfusion (by 69 +/- 17%, n = 5, P < 0.05). After chronic NCN and PSN transection brain topical superfusion of CGRP-(8-37) (5 x 10(-7) M) reduced CSD hyperperfusion slightly by 9.5 +/- 5% (n = 3). Atropine (10(-4) M) afforded a decrease by 17 +/- 6% (n = 3). These reductions were not statistically significant. We conclude that CSD-associated hyperperfusion is mediated in part by a depolarization of trigeminal sensory and parasympathetic nerve fibers, resulting in a release of vasoactive trigeminal and parasympathetic neurotransmitters.

The mathematics of SELEX against complex targets

We have developed a computer model for the simulation of simultaneous SELEX against multiple targets. The model assumes equilibrium behavior for the formation of binary ligand:target complexes, and that there is no ligand:ligand or target:target interaction. Target concentrations, ligand concentrations, and affinity distributions of the initial ligand pool for each individual target may be set by the user. We have used this program to gain an understanding of how the presence of multiple targets affects the selection process. In most cases, we find that SELEX is capable of generating different ligands for the different targets in a heterogeneous mixture, regardless of large variations in target concentrations and ligand:target affinities. A low relative partitioning efficiency (the efficiency with which ligands complexed with a target are separated from free ligands) for a target in a mixture gives a greatly reduced rate of selection of high-affinity ligands to that target. The ratio of each high-affinity ligand to its individual target within a pool of ligands selected for binding against a mixture of targets is approximately proportional to the concentration of the target multiplied by the ligand:target partitioning efficiency.

High affinity ligands from in vitro selection: complex targets

Human red blood cell membranes were used as a model system to determine if the systematic evolution of ligands by exponential enrichment (SELEX) methodology, an in vitro protocol for isolating high-affinity oligonucleotides that bind specifically to virtually any single protein, could be used with a complex mixture of potential targets. Ligands to multiple targets were generated simultaneously during the selection process, and the binding affinities of these ligands for their targets are comparable to those found in similar experiments against pure targets. A secondary selection scheme, deconvolution-SELEX, facilitates rapid isolation of the ligands to targets of special interest within the mixture. SELEX provides high-affinity compounds for multiple targets in a mixture and might allow a means for dissecting complex biological systems.

Cortical spreading depression-associated hyperemia in rats: involvement of serotonin

We investigated whether the vasoactive neurotransmitter serotonin (5-HT) is involved in cortical spreading depression (CSD)-associated hyperemia in the rat. We focused on the 5-HT2 receptor, which is engaged in 5-HT induced small arteriolar relaxation in cats, as well as on the 5-HT1D/1B receptor, the binding site of the potent antimigraine drug sumatriptan. In male barbiturate anaesthetized Wistar rats (n=25) CSDs were elicited by brain topical application of 1 M KCl, and the DC-potential and regional cerebral blood flow (rCBF, by Laser Doppler flowmetry) were measured over the same hemisphere through dura and thinned bone, respectively. Intravenous application of 8 mg/kg of the 5-HT2A/2C receptor antagonist ritanserin (group I; n=8) significantly reduced the hyperperfusion amplitude during CSD by approximately 44% (p<0.05, from 342+/-124 to 194+/-97%, baseline before CSD=100%), and prolonged its duration by approx. 30%. Vehicle alone (group II; n=4) did not affect CSD hyperperfusion. The highly selective 5-HT1D/1B receptor agonist 311C90 was given in two doses: 100 micrograms/kg i.v. (n=5) had no effect on CSD hyperperfusion, while 800 micrograms/kg (n=5) increased hyperperfusion significantly (p<0.05, from 224+/-86 to 310+/-148%). We conclude that serotonin is, probably via 5-HT2 receptors, involved in the modulation of the regional cerebral blood flow increase during CSD. Novel highly selective receptor antagonists may help to discriminate the differential contribution of various 5-HT receptor subspecies.

SELEX and the evolution of genomes

The interrupted genome structures of complex multicellular organisms have most likely changed the evolution of the regulation of metabolism and development. Wasted intron sequences make regulation of gene expression in (for example) mammals appear to be unnecessarily complicated. The recent discoveries that globular RNA molecules are very much like the antigen-combining sites of antibodies suggest that intronic RNA may be used to help solve the problems raised by this complexity.

RNA aptamers to the peptidyl transferase inhibitor chloramphenicol

BACKGROUND

The problem of how macromolecules adopt specific shapes to recognize small molecules in their environment is readily addressed through in vitro selections (the SELEX protocol). RNA-antibiotic interactions are particularly attractive systems for study because they provide an opportunity to expand our understanding of molecular recognition by RNA and to facilitate ribosomal modeling. Specifically, the antibiotic chloramphenicol (Cam) naturally binds bacterial ribosomes in the 'peptidyl transferase loop' of 23S ribosomal RNA to inhibit peptide bond formation.

RESULTS

We identified Cam-binding RNA molecules ('aptamers') from two independent initial random RNA populations. Boundary determinations, ribonuclease S1 sensitivity analyses and the activity of truncated minimal RNAs identified a structural motif that is shared by sequences from both selections. The pseudosymmetric motif consists of a highly conserved central helix of five to six base pairs flanked by A-rich bulges and additional helices. Addition of Cam prior to ribonuclease S1 protected nucleotides in the conserved cores from cleavage. Reselection from a pool of mutated variants of the minimal aptamer further refined the sequence requirements for binding. Finally, we used proton nuclear magnetic resonance (NMR) to establish a 1:1 RNA: Cam stoichiometry of the complex. Both the protection and NMR data both show that Cam stabilizes the active fold of this aptamer.

CONCLUSIONS

There are many different RNA sequences that can bind Cam. The Cam aptamers that we examined have a well-defined secondary structure with a binding pocket that appears to be stabilized by Cam. This RNA motif superficially resembles the Cam-binding site in 23S rRNA, although further work is needed to establish the significance of these similarities.