760 IMPROVING THE MANAGEMENT AND DURATION OF RESOLUTION OF ACUTE KIDNEY INJURY IN THE ELDERLY

Introduction

Acute Kidney Injury (AKI) is prevalent in elderly populations due to several factors: polypharmacy, anatomic/physiologic changes of the kidneys associated with aging. AKI can contribute to increased length of stay, morbidity and mortality. This audit sets out to establish if the guidance established by NICE is being followed and how it may be better implemented.

Method

This study audited patients ≥65 years, who were admitted with AKI/developed an AKI during admission. Patients were excluded if they were on renal replacement therapy or under palliative care. Data was collected from case notes and Clinical Work Station. Data collection points used included: senior review within 24 hours; assessment of fluid status; medication review; strict fluid balance; examine for retention +/− catheter; daily U&E and appropriate imaging. Our independent variable was an AKI sticker, this included a revised checklist for above data collection points that was applied to patients’ medical notes. In addition to this, we used posters on appropriate wards which explained the guidance and management of AKI. Awareness was continued by presenting at Care of The Elderly teaching and medical grand round. Then re-audited the following month.

Results

Both cycles involved 45 patients. After implementation, improvements in urine analysis (5%vs35%), assessments of retention (0%vs38%) and assessments of fluid balance (55%vs78%) were seen. In cycle 2, medication was reviewed more frequently, specifically a 30% increase in the review of nephrotoxics. While senior review within 24 hours remains high in both cycles. We measured the outcome by checking the resolution time of AKI. Mean Resolution time was reduced by 1.4 days.

Conclusion

This audit has demonstrated an increase in the optimisation of the management of AKI through ensuring all appropriate interventions and examinations are completed and reducing resolution time by using stickers and the posters.

Hyperosmolar blood-brain barrier opening using intra-arterial injection of hyperosmotic mannitol in mice under real-time MRI guidance

The blood-brain barrier (BBB) is the main obstacle to the effective delivery of therapeutic agents to the brain, compromising treatment efficacy for a variety of neurological disorders. Intra-arterial (IA) injection of hyperosmotic mannitol has been used to permeabilize the BBB and improve parenchymal entry of therapeutic agents following IA delivery in preclinical and clinical studies. However, the reproducibility of IA BBB manipulation is low and therapeutic outcomes are variable. We demonstrated that this variability could be highly reduced or eliminated when the procedure of osmotic BBB opening is performed under the guidance of interventional MRI. Studies have reported the utility and applicability of this technique in several species. Here we describe a protocol to open the BBB by IA injection of hyperosmotic mannitol under the guidance of MRI in mice. The procedures (from preoperative preparation to postoperative care) can be completed within ~1.5 h, and the skill level required is on par with the induction of middle cerebral artery occlusion in small animals. This MRI-guided BBB opening technique in mice can be utilized to study the biology of the BBB and improve the delivery of various therapeutic agents to the brain.

Deuterium oxide as a contrast medium for real-time MRI-guided endovascular neurointervention

Rationale: Endovascular intervention plays an important role in the treatment of various diseases, in which MRI-guidance can potentially improve precision. However, the clinical applications of currently available contrast media, including Gadolinium-based contrast agents and superparamagnetic iron oxide particles (SPIO), are hindered by safety concerns. In the present study, we sought to develop D2O as a novel contrast agent for guiding endovascular neurointervention. Methods: Animal studies were approved by institutional ACUC and conducted using an 11.7 T Bruker Biospec system and a 3T Siemens Trio clinical scanner for rodent and canine imaging, respectively. The locally selective blood brain barrier opening (BBBO) in rat brains was obtained by intraarterial (IA) injection of mannitol. The dynamic T2w* EPI MRI sequence was used to study the trans-catheter perfusion territory by IA administered SPIO before mannitol administration, whereas a dynamic T1w FLASH sequence was used to acquire Gd contrast-enhanced MRI for assessing BBBO after injection of mannitol. The contrast generated by D2O assessed by either EPI or FLASH methods was compared with the corresponding results assessed by SPIO or Gd. The utility of D2O MRI was also demonstrated to guide drug delivery to glioma in a mouse model. Finally, the clinical utility of D2O-MRI was demonstrated in a canine model. Results: Our study has shown that the contrast generated by D2O can be used to precisely delineate trans-catheter perfusion territory in both small and large animals. The perfusion territories determined by D2O-MRI show moderate correlation with those by SPIO-MRI (Spearman coefficient r = 0.5234, P < 0.001). Moreover, our results show that the perfusion territory determined by D2O-MRI can successfully predict the areas with BBBO after mannitol treatment similar to that assessed by Gd-MRI (Spearman coefficient r = 0.6923, P < 0.001). Using D2O-MRI as imaging guidance, the optimal infusion rate in the mouse brain was determined to be 150 µL/min to maximize the delivery efficacy to the tumor without serious off-target delivery to the brain parenchyma. The enhanced drug delivery of antibodies to the brain tumor was confirmed by fluorescence imaging. Conclusion: Our study demonstrated that D2O can be used as a negative MRI contrast medium to guide endovascular neurointervention. The established D2O -MRI method is safe and quantitative, without the concern of contrast accumulation. These qualities make it an attempting approach for a variety of endovascular procedures.

New Mechanistic Insights, Novel Treatment Paradigms, and Clinical Progress in Cerebrovascular Diseases

The past decade has brought tremendous progress in diagnostic and therapeutic options for cerebrovascular diseases as exemplified by the advent of thrombectomy in ischemic stroke, benefitting a steeply increasing number of stroke patients and potentially paving the way for a renaissance of neuroprotectants. Progress in basic science has been equally impressive. Based on a deeper understanding of pathomechanisms underlying cerebrovascular diseases, new therapeutic targets have been identified and novel treatment strategies such as pre- and post-conditioning methods were developed. Moreover, translationally relevant aspects are increasingly recognized in basic science studies, which is believed to increase their predictive value and the relevance of obtained findings for clinical application.This review reports key results from some of the most remarkable and encouraging achievements in neurovascular research that have been reported at the 10th International Symposium on Neuroprotection and Neurorepair. Basic science topics discussed herein focus on aspects such as neuroinflammation, extracellular vesicles, and the role of sex and age on stroke recovery. Translational reports highlighted endovascular techniques and targeted delivery methods, neurorehabilitation, advanced functional testing approaches for experimental studies, pre-and post-conditioning approaches as well as novel imaging and treatment strategies. Beyond ischemic stroke, particular emphasis was given on activities in the fields of traumatic brain injury and cerebral hemorrhage in which promising preclinical and clinical results have been reported. Although the number of neutral outcomes in clinical trials is still remarkably high when targeting cerebrovascular diseases, we begin to evidence stepwise but continuous progress towards novel treatment options. Advances in preclinical and translational research as reported herein are believed to have formed a solid foundation for this progress.

Vestibular Implant Imaging

Analogous to hearing restoration via cochlear implants, vestibular function could be restored via vestibular implants that electrically stimulate vestibular nerve branches to encode head motion. This study presents the technical feasibility and first imaging results of CT for vestibular implants in 8 participants of the first-in-human Multichannel Vestibular Implant Early Feasibility Study. Imaging characteristics of 8 participants (3 men, 5 women; median age, 59.5 years; range, 51-66 years) implanted with a Multichannel Vestibular Implant System who underwent a postimplantation multislice CT (n = 2) or flat panel CT (n = 6) are reported. The device comprises 9 platinum electrodes inserted into the ampullae of the 3 semicircular canals and 1 reference electrode inserted in the common crus. Electrode insertion site, positions, length and angle of insertion, and number of artifacts were assessed. Individual electrode contacts were barely discernible in the 2 participants imaged using multislice CT. Electrode and osseous structures were detectable but blurred so that only 12 of the 18 stimulating electrode contacts could be individually identified. Flat panel CT could identify all 10 electrode contacts in all 6 participants. The median reference electrode insertion depth angle was 9° (range, -57.5° to 45°), and the median reference electrode insertion length was 42 mm (range, -21-66 mm). Flat panel CT of vestibular implants produces higher-resolution images with fewer artifacts than multidetector row CT, allowing visualization of individual electrode contacts and quantification of their locations relative to vestibular semicircular canals and ampullae. As multichannel vestibular implant imaging improves, so will our understanding of the relationship between electrode placement and vestibular performance.

SCIDOT-08. CHILDREN’S BRAIN TUMOUR DRUG DELIVERY CONSORTIUM (CBTDDC)

INTRODUCTION

The brain tumour community has seen significant progress in the discovery of new therapeutic targets and anticancer drugs. Unfortunately, advances in how to deliver drugs to the brain lag behind. The blood-brain barrier restricts the entry of many small-molecule drugs and nearly all large molecule drugs that have been developed to treat brain disorders.

METHODS

Following an international CNS drug delivery workshop in 2016, we were awarded funding from Children with Cancer UK to launch the Children’s Brain Tumour Drug Delivery Consortium (CBTDDC; www.cbtddc.org; @cbtddc).

RESULTS

The CBTDDC launched in 2017 (in Europe and the US) to raise awareness of the challenge of drug delivery in childhood brain tumours, and to initiate and strengthen research collaborations to accelerate the development of drug delivery systems. We ran a Workshop on Drug Delivery to the Brain, attracting 52 delegates from the UK, Belgium, Spain and Portugal. We liaised with UK-based funders over the drug delivery agenda, and with UK policy makers. In the US, we jointly organised the SIGN2019 meeting and we are currently liaising with the leads of Project ‘All In’ DIPG about how we can lend our support to this project. As of June 2019, 150 individuals have registered with the consortium, representing researchers, clinicians, charities, patient groups and industry. These stakeholders represent 70 research institutions, covering 15 countries (France, UK, Italy, Sweden, The Netherlands, USA, Greece, Germany, Belgium, Cuba, Denmark, Spain, Portugal, Israel and Egypt). We host a freely accessible online collaborative research database, containing the details of over 70 researchers.

CONCLUSION

We believe that collaboration between clinicians and multi-disciplinary researchers is vital to solving the brain tumour drug delivery challenge. We hope to raise awareness of the CBTDDC, and to extend our invitation for collaborators to join the consortium, through SCIDOT’s unrivalled drug delivery platform.

Real-Time MRI Guidance for Reproducible Hyperosmolar Opening of the Blood-Brain Barrier in Mice

The blood-brain barrier (BBB) prevents effective delivery of most therapeutic agents to the brain. Intra-arterial (IA) infusion of hyperosmotic mannitol has been widely used to open the BBB and improve parenchymal targeting, but the extent of BBB disruption has varied widely with therapeutic outcomes often being unpredictable. In this work, we show that real-time MRI can enable fine-tuning of the infusion rate to adjust and predict effective and local brain perfusion in mice, and thereby can be allowed for achieving the targeted and localized BBB opening (BBBO). Both the reproducibility and safety are validated by MRI and histology. The reliable and reproducible BBBO we developed in mice will allow cost-effective studies on the biology of the BBB and drug delivery to the brain. In addition, the IA route for BBBO also permits subsequent IA delivery of a specific drug during the same procedure and obtains high targeting efficiency of the therapeutic agent in the targeted tissue, which has great potential for future clinical translation in neuro-oncology, regenerative medicine and other neurological applications.

Imaging the DNA Alkylator Melphalan by CEST MRI: An Advanced Approach to Theranostics

Brain tumors are among the most lethal types of tumors. Therapeutic response variability and failure in patients have been attributed to several factors, including inadequate drug delivery to tumors due to the blood-brain barrier (BBB). Consequently, drug delivery strategies are being developed for the local and targeted delivery of drugs to brain tumors. These drug delivery strategies could benefit from new approaches to monitor the delivery of drugs to tumors. Here, we evaluated the feasibility of imaging 4-[bis(2-chloroethyl)amino]-l-phenylalanine (melphalan), a clinically used DNA alkylating agent, using chemical exchange saturation transfer magnetic resonance imaging (CEST MRI), for theranostic applications. We evaluated the physicochemical parameters that affect melphalan's CEST contrast and demonstrated the feasibility of imaging the unmodified drug by saturating its exchangeable amine protons. Melphalan generated a CEST signal despite its reactivity in an aqueous milieu. The maximum CEST signal was observed at pH 6.2. This CEST contrast trend was then used to monitor therapeutic responses to melphalan in vitro. Upon cell death, the decrease in cellular pH from ∼7.4 to ∼6.4 caused an amplification of the melphalan CEST signal. This is contrary to what has been reported for other CEST contrast agents used for imaging cell death, where a decrease in the cellular pH following cell death results in a decrease in the CEST signal. Ultimately, this method could be used to noninvasively monitor melphalan delivery to brain tumors and also to validate therapeutic responses to melphalan clinically.

Salicylic acid analogues as chemical exchange saturation transfer MRI contrast agents for the assessment of brain perfusion territory and blood-brain barrier opening after intra-arterial infusion

The blood-brain barrier (BBB) is a major obstacle for drug delivery to the brain. Predicted, focal opening of the BBB through intra-arterial infusion of hyperosmolar mannitol is feasible, but there is a need to facilitate imaging techniques (e.g. MRI) to guide interventional procedures and assess the outcomes. Here, we show that salicylic acid analogues (SAA) can depict the brain territory supplied by the catheter and detect the BBB opening, through chemical exchange saturation transfer (CEST) MRI. Hyperosmolar SAA solutions themselves are also capable of opening the BBB, and, when multiple SAA agents were co-injected, their locoregional perfusion could be differentiated.

Hormonal evidence supports the theory of selection in utero

OBJECTIVES

Antagonists in the debate over whether the maternal stress response during pregnancy damages or culls fetuses have invoked the theory of selection in utero to support opposing positions. We describe how these opposing arguments arise from the same theory and offer a novel test to discriminate between them. Our test, rooted in reports from population endocrinology that human chorionic gonadotropin (hCG) signals fetal fitness, contributes not only to the debate over the fetal origins of illness, but also to the more basic literature concerned with whether and how natural selection in utero affects contemporary human populations.

METHODS

We linked maternal serum hCG measurements from prenatal screening tests with data from the California Department of Public Health birth registry for the years 2001-2007. We used time series analysis to test the association between the number of live-born male singletons and median hCG concentration among males in monthly gestational cohorts.

RESULTS

Among the 1.56 million gestations in our analysis, we find that median hCG levels among male survivors of monthly conception cohorts rise as the number of male survivors falls.

RESULTS

Elevated median hCG among relatively small male birth cohorts supports the theory of selection in utero and suggests that the maternal stress response culls cohorts in gestation by raising the fitness criterion for survival to birth.

Vein of Galen malformations: epidemiology, clinical presentations, management

The vein of Galen aneurysmal malformation is a congenital vascular malformation that comprises 30% of the pediatric vascular and 1% of all pediatric congenital anomalies. Treatment is dependent on the timing of presentation and clinical manifestations. With the development of endovascular techniques, treatment paradigms have changed and clinical outcomes have significantly improved. In this article, the developmental embryology, clinical features and pathophysiology, diagnostic workup, and management strategies are reviewed.

Intracranial dural arteriovenous fistulas: classification, imaging findings, and treatment

Intracranial DAVFs are pathologic dural-based shunts and account for 10%-15% of all intracranial arteriovenous malformations. These malformations derive their arterial supply primarily from meningeal vessels, and the venous drainage is either via dural venous sinuses or through the cortical veins. DAVFs have a reported association with dural sinus thrombosis, venous hypertension, previous craniotomy, and trauma, though many lesions are idiopathic. The diagnosis is dependent on a high level of clinical suspicion and high-resolution imaging. Cross-sectional imaging techniques by using CT and MR imaging aid in the diagnosis, but conventional angiography remains the most accurate method for complete characterization and classification of DAVFs. The pattern of venous drainage observed on dynamic vascular imaging determines the type of DAVF and correlates with the severity of symptoms and the risk of hemorrhage.

Expression of inflammatory cytokines by adipose tissue from patients with endometrial cancer

Obesity results in increased mortality from many forms of cancer. We looked at the levels of gene expression for TNFalpha, IL-6, IkappaB kinase (inhibitor of NF-kappaB), CD 68 (glycoprotein expressed on macrophages) and leptin in samples of adipose tissue from individuals with endometrial cancer versus patients with benign conditions. This is a prospective study which included patients of a gynecologic oncology group. A piece of omental tissue was harvested from them during surgery. RNA was purified from all samples. Relative amounts of RNA for IkappaB, TNFalpha, IL-6, CD68 and leptin were calculated. Pearson's correlation method was used to correlate RNA levels with BMI. Logistic regression method was used to compare gene expression for cancer and control groups. The total sample size was 56 (24 endometrial cancer and 32 controls). IkappaB, TNFalpha and IL-6 levels increased linearly with increasing BMI in the control group. There was no correlation of IkappaB, TNFalpha, IL-6 or CD-68 levels with cancer status of the patients. Leptin had a weak protective effect against endometrial cancer (odds ratio = 0.92). Obesity is associated with increased expression of certain inflammatory cytokines in the adipose tissue. However, increased levels of these inflammatory markers in the adipose tissue of the omentum are not associated with presence of endometrial cancer.

Endovascular management of vein of Galen aneurysmal malformations. Influence of the normal venous drainage on the choice of a treatment strategy

INTRODUCTION

Vein of Galen arteriovenous malformations (VGAM) are rare intracranial vascular lesions mostly involving young children. Endovascular therapy is the current standard of care. Albeit interventional techniques have greatly reduced the once dismal vital and functional prognoses previously associated with these lesions, the treatment of VGAMs remains a complex therapeutic challenge.

DISCUSSIONS

This article reviews the available endovascular options for VGAM therapy, emphasizing three points that we have identified as critical in our practice for the establishment of a treatment strategy: (1) the importance of the deep cerebral venous anatomy, in particular the existence of normal drainage through the Galenic system in spite of the VGAM; (2) the concept of treatment staging, for arterial as well as for venous interventions; and (3) the definition of a therapeutic goal that can be attained at a reasonable cost in terms of complication risks and functional outcome.

Acupuncture-point stimulation for chemotherapy-induced nausea or vomiting

BACKGROUND

There have been recent advances in chemotherapy-induced nausea and vomiting using 5-HT(3) inhibitors and dexamethasone. However, many still experience these symptoms, and expert panels encourage additional methods to reduce these symptoms.

OBJECTIVES

The objective was to assess the effectiveness of acupuncture-point stimulation on acute and delayed chemotherapy-induced nausea and vomiting in cancer patients.

SEARCH STRATEGY

We searched MEDLINE, EMBASE, PsycLIT, MANTIS, Science Citation Index, CCTR (Cochrane Controlled Trials Registry), Cochrane Complementary Medicine Field Trials Register, Cochrane Pain, Palliative Care and Supportive Care Specialized Register, Cochrane Cancer Specialized Register, and conference abstracts.

SELECTION CRITERIA

Randomized trials of acupuncture-point stimulation by any method (needles, electrical stimulation, magnets, or acupressure) and assessing chemotherapy-induced nausea or vomiting, or both.

DATA COLLECTION AND ANALYSIS

Data were provided by investigators of the original trials and pooled using a fixed effect model. Relative risks were calculated on dichotomous data. Standardized mean differences were calculated for nausea severity. Weighted mean differences were calculated for number of emetic episodes.

MAIN RESULTS

Eleven trials (N = 1247) were pooled. Overall, acupuncture-point stimulation of all methods combined reduced the incidence of acute vomiting (RR = 0.82; 95% confidence interval 0.69 to 0.99; P = 0.04), but not acute or delayed nausea severity compared to control. By modality, stimulation with needles reduced proportion of acute vomiting (RR = 0.74; 95% confidence interval 0.58 to 0.94; P = 0.01), but not acute nausea severity. Electroacupuncture reduced the proportion of acute vomiting (RR = 0.76; 95% confidence interval 0.60 to 0.97; P = 0.02), but manual acupuncture did not; delayed symptoms for acupuncture were not reported. Acupressure reduced mean acute nausea severity (SMD = -0.19; 95% confidence interval -0.37 to -0.01; P = 0.04) but not acute vomiting or delayed symptoms. Noninvasive electrostimulation showed no benefit for any outcome. All trials used concomitant pharmacologic antiemetics, and all, except electroacupuncture trials, used state-of-the-art antiemetics.

AUTHORS' CONCLUSIONS

This review complements data on post-operative nausea and vomiting suggesting a biologic effect of acupuncture-point stimulation. Electroacupuncture has demonstrated benefit for chemotherapy-induced acute vomiting, but studies combining electroacupuncture with state-of-the-art antiemetics and in patients with refractory symptoms are needed to determine clinical relevance. Self-administered acupressure appears to have a protective effect for acute nausea and can readily be taught to patients though studies did not involve placebo control. Noninvasive electrostimulation appears unlikely to have a clinically relevant impact when patients are given state-of-the-art pharmacologic antiemetic therapy.

Cystic fibrosis screening in newborns: results from existing programs

Newborn screening for cystic fibrosis (CF) provides early identification and initiation of treatment to infants with this fatal and often misdiagnosed genetic disease. Although reports of health benefits continue to mount from decade-old screening programs in Wisconsin, France, and Australia, newborn screening for CF is still a highly debated topic in genetic policy development. This article summarizes the literature published between May 2000 and April 2001 regarding the health benefits, risks, cost-effectiveness, and programmatic issues of newborn screening for CF. The literature consistently shows evidence of benefits and lack of harm from newborn screening for CF.

The relationship of neighborhood socioeconomic characteristics to birthweight among 5 ethnic groups in California

OBJECTIVES

This study sought to examine relationships between neighborhood socioeconomic characteristics and birthweight, accounting for individual socioeconomic characteristics, among 5 ethnic groups.

METHODS

Birth records were linked to census block-group data for 22 304 women delivering infants at 18 California hospitals during 1994-1995. Information on income and additional factors was obtained from a surveyed subset of 8457 women. Neighborhood levels of poverty, unemployment, and education were examined.

RESULTS

After adjustment for mothers' individual socioeconomic characteristics and other risk factors, less-favorable neighborhood socioeconomic characteristics were associated with lower birthweight among Blacks and Asians. No consistent relationship between neighborhood socioeconomic characteristics and birthweight was found among Whites, US-born Latinas, or foreign-born Latinas overall, but birthweight increased with less-favorable neighborhood socioeconomic characteristics among foreign-born Latinas in high-poverty or high-unemployment neighborhoods. These findings were not explained by measured behavioral or cultural factors.

CONCLUSIONS

In addition to individual socioeconomic characteristics, living in neighborhoods that are less socioeconomically advantaged may differentially influence birthweight, depending on women's ethnicity and nativity.

Access to care for children of the working poor

CONTEXT

Recent evidence suggests that children in working poor families lack health resources, placing them at risk for inadequate access to care.

OBJECTIVES

To examine financial and nonfinancial access and utilization of health services among children in working poor families, and to compare these data with those of children from both nonworking poor and moderate to affluent families.

DESIGN

A cross-sectional study of 13 785 children younger than 18 years.

PARTICIPANTS

Subjects from the 1997 National Health Interview Survey.

MAIN OUTCOME MEASURES

Prevalence and continuity of health insurance coverage, of delayed or missed care, and of unmet care needs; presence and type of usual source of care; and the amount of visits to physicians, emergency departments, and hospitals.

RESULTS

Compared with children of nonworking poor parents and moderate to affluent children, more working poor children were uninsured (22% vs 12% and 5%, respectively; P<.01) and experienced disruptions in insurance coverage (P<.01). After adjusting for other covariates, disparities in insurance coverage and continuity persisted, as did delays in care and unmet care needs; these delays were far higher for the working poor. Although these children had access to a regular source of care and had utilization rates comparable with those of other poor children, they differed markedly from moderate to affluent children on structural access and utilization (adjusted odds ratios, 1.5-3.4).

CONCLUSIONS

Children in working poor families experience far more barriers to care than other children. Health insurance expansions through the Children's Health Insurance Program and Medicaid, which reduce financial and nonfinancial barriers to care, may help correct these disparities.

Multilevel analyses of neighbourhood socioeconomic context and health outcomes: a critical review

PURPOSE

Interest in the effects of neighbourhood or local area social characteristics on health has increased in recent years, but to date the existing evidence has not been systematically reviewed. Multilevel or contextual analyses of social factors and health represent a possible reconciliation between two divergent epidemiological paradigms-individual risk factor epidemiology and an ecological approach.

DATA SOURCES

Keyword searching of Index Medicus (Medline) and additional references from retrieved articles.

STUDY SELECTION

All original studies of the effect of local area social characteristics on individual health outcomes, adjusted for individual socioeconomic status, published in English before 1 June 1998 and focused on populations in developed countries.

DATA SYNTHESIS

The methodological challenges posed by the design and interpretation of multilevel studies of local area effects are discussed and results summarised with reference to type of health outcome. All but two of the 25 reviewed studies reported a statistically significant association between at least one measure of social environment and a health outcome (contextual effect), after adjusting for individual level socioeconomic status (compositional effect). Contextual effects were generally modest and much smaller than compositional effects.

CONCLUSIONS

The evidence for modest neighbourhood effects on health is fairly consistent despite heterogeneity of study designs, substitution of local area measures for neighbourhood measures and probable measurement error. By drawing public health attention to the health risks associated with the social structure and ecology of neighbourhoods, innovative approaches to community level interventions may ensue.

Unfriendly shores: how immigrant children fare in the U.S. health system

The proliferation of poor immigrant children in the United States raises concern about their high uninsurance rates and access to care. We examined the joint effects of health insurance status and place of birth on use of health services by children of the working poor. Of foreign-born children, 52 percent were uninsured and 66 percent had a regular care source, compared with 20 percent and 92 percent, respectively, of native-born children. Foreign-born uninsured children were less likely than their native-born peers were to have a regular care source or to have sought care. Health insurance and immigration policies must act in concert to increase health care access for foreign-born children.

The validity of information on "race" and "Hispanic ethnicity" in California birth certificate data

OBJECTIVE

To evaluate the validity of racial/ethnic information in California birth certificate data.

DATA SOURCES

Computerized birth certificate data and postpartum interviews with California mothers.

STUDY DESIGN AND DATA COLLECTION

Birth certificates were matched with face-to-face structured postpartum interviews with 7,428 mothers to compare racial/ethnic information between the two data sources. Interviews were conducted in Spanish or English during delivery stays at 16 California hospitals, 1994-1995.

PRINCIPAL FINDINGS

The sensitivity of racial/ethnic classification in birth certificate data was very high (94 percent to 99 percent) for African Americans, Asians/Pacific Islanders, Europeans/Middle Easterners, and Latinas (Hispanics). For Native Americans, however, the sensitivity was only 54 percent. The positive predictive value of birth certificate classification of race/ethnicity was high for all racial/ethnic groups (96 percent to 97 percent).

CONCLUSIONS

Despite limited training of birth clerks, the maternal racial/ethnic information in California birth certificate data appears to be a valid measure of self-identified race and Hispanic ethnicity for groups other than Native Americans.

Barriers to timely prenatal care among women with insurance: the importance of prepregnancy factors

OBJECTIVE

This study, designed to avoid methodologic limitations of previous research, aimed to identify the important noninsurance barriers to timely prenatal care.

METHODS

We identified a subsample of a cross-sectional statewide representative postpartum survey conducted in California during 1994-1995, focusing on 3071 low-income women with Medi-Cal or private coverage throughout pregnancy.

RESULTS

Twenty-eight percent of those women had untimely care, although only 6% were unaware of their pregnancies during the first trimester. Controlling for numerous sociodemographic factors; knowledge, attitudes, beliefs, and behaviors; stressful life circumstances; and logistic obstacles that might deter seeking or receiving care, the following risk factors for untimely care were significant and experienced by more than one fifth of women: unwanted or unplanned pregnancy (affecting 43% and 66% of women, respectively), no regular provider before pregnancy (affecting 22% of women), and no schooling beyond high school (affecting 76% of women). Transportation problems, affecting 8% of women, appeared to be the only significant logistic barrier to timely care.

CONCLUSION

Improving timeliness of prenatal care among low-income women with third-party coverage is likely to require broad social and health policies that focus on factors affecting women before pregnancy. Assistance with transportation could contribute to more timely care for some low-income women, but programs focusing primarily on other noninsurance barriers during pregnancy might not substantially improve the timeliness of care, at least among low-income women with third-party coverage.

Does membrane lipid profile explain chilling sensitivity and membrane lipid phase transition of spermatozoa and oocytes?

Ram, fowl and bee spermatozoa, and oocytes of cows and zebrafish were used to study lipid membrane profiles, chilling sensitivity and lipid-phase transitions. The integrity of the membranes was determined by carboxyfluorescein diacetate (CFDA) staining following exposure for 15 minutes to low temperatures. Ram and fowl spermatozoa showed different degrees of loss of membrane integrity. Surprisingly, bee spermatozoa did not show any sensitivity to chilling, and their membranes remained intact down to 0 degree C. In bovine oocytes (at the GV stage) chilling injury was very severe at 16 degree C (membrane integrity decreased by 50%). Lipid phase transition (LPT) and membrane fluidity, which were evaluated by Fourier transform infrared (FTIR) microscopy, and fluorescence polarisation, showed phase transitions at the same temperatures as caused damage (between 30 and 12 degree C). The membrane lipid profiles showed high concentrations of polyunsaturated fatty acids (PUFA) in cold-sensitive ram spermatozoa and zebrafish oocytes, but the ratio between PUFA and saturated fatty acids was highest in cold-resistant bee spermatozoa and lowest in cold-sensitive bovine oocytes. These results suggest a close relationship among cold susceptibility, lipid phase transition and lipids profile in animal gametes.

Chilling sensitivity in zebrafish (Brachydanio rerio) oocytes is related to lipid phase transition

Oocytes of zebrafish were used to study chilling sensitivity and membrane lipid phase transitions in tropical fish. The oocytes were divided into two groups: small (without yolk, <0.1mm) and large (with yolk, >0.1mm). After exposure of the oocytes to different temperatures (25, 22, 19, 16, 12, 8, 0, -8+0.5 degree C) for 15 minutes, the integrity of their membranes was determined by carboxyfluorescein diacetate (CFDA) staining. At 16 and 12 degree C, damage was maximum (membrane integrity decreased by 50%) for small and large sizes, respectively. Lipid phase transition (LPT), which was evaluated using Fourier transform infrared (FTIR) microscopy, indicated phase transitions at the same temperatures at which damage was maximal (between 22 and 12 degree C).In another series of experiments, the chilling sensitivity of oocytes taken from zebrafish which had been held at 16 degree C for different periods of time (0, 15, 30, 60 minutes) was determined as described above. In small oocytes membrane integrity decreased after 15 minutes, and in large oocytes integrity decreased after 30 minutes. Chilling sensitivity was also measured in oocytes from zebrafish that had been held at 16 degree C for 30 minutes and then rewarmed to 28 degree C for 2 hours. Despite this recovery period, the integrity of the oocytes remained low. We suggest that chilling sensitivity in zebrafish oocytes is related to lipid phase transition of their membranes and starts at 10 degree C below the physiological temperature

Kinetic and temporal factors influence chilling injury to germinal vesicle and mature bovine oocytes

In this study we examined the effects of low, above freezing temperatures on the viability and functionality of bovine oocytes. Germinal vesicle (GV) stage and in vitro matured oocytes (MII) were exposed to various combinations of time (15 and 60 min) and temperature (4, 16, 23, and 39 degrees C). After being treated, the ability of oocytes to undergo maturation and fertilization in vitro was examined, as well as their viability assayed by two fluorescent probes, fluorescein diacetate (FDA) and 5-carboxyfluorescein diacetate (cFDA). Cooling GV oocytes to 16 degrees C for 15 min reduced the fertilization rate by more than 40%, compared with those left at 39 degrees C. Surprisingly, cooling oocytes to 4 degrees C reduced the fertilization rate by only 10% compared with control. Exposing GV oocytes to temperatures below 23 degrees C reduced their viability. Similar to the reduction in fertilization, the viability of GV oocytes after exposure to 16 degrees C was reduced by more than 50%, whereas exposure to 4 degrees C reduced it by only 9%. Viability measurements using FDA and cFDA gave comparable results and showed a similar trend. The viability of MII oocytes and of GV oocytes pretreated with butylated hydroxytoluene, following exposure to low temperatures, was higher compared with that of GV controls. We interpret these results as indicating chilling effects on membrane integrity. Improving the chilling resistance of bovine oocytes may facilitate their short- and long-term preservation.

The role of Medicaid in ensuring children's access to care

CONTEXT

Congress enacted a series of laws beginning in the mid 1980s to expand Medicaid eligibility for children, especially those in poor families. As a result, Medicaid enrollment of children has nearly doubled over the past decade.

OBJECTIVE

To assess the effectiveness of Medicaid in improving access to and use of health services by poor children.

DESIGN

Analysis of cross-sectional survey data from the 1995 National Health Interview Survey. Poor children with Medicaid were compared to poor children without insurance and nonpoor children with private insurance.

SETTING AND PARTICIPANTS

A total of 29711 children younger than 18 years (3716 poor children with Medicaid, 1329 poor children without insurance, 14609 nonpoor children with private insurance, and 10057 children with other combinations of poverty and insurance status) included in a nationally representative stratified probability sample of the US noninstitutionalized population.

MAIN OUTCOME MEASURES

Usual source of care, access to a regular clinician, unmet health needs, and use of physician services.

RESULTS

Poor children with Medicaid compared to poor children without health insurance experienced superior access across all measured dimensions of health care, including presence of a usual source of care (95.6% vs 73.8%), frequency of unmet health needs (2.1 % vs 5.9%), and use of medical services (eg, > or =1 physician contact in past year) (83.9% vs 60.7%). Poor children with Medicaid compared to nonpoor children with private insurance used similar levels of physician services (83.9% vs 84%), but were more likely to have unmet health needs (2.1 % vs 0.6%) and were less likely to have a usual source of care (95.6% vs 97.4%).

CONCLUSION

Medicaid is associated with improvements in access to care and use of services. However, there remains room for improvement when Medicaid is judged against private health insurance. The Balanced Budget Act of 1997 contains several Medicaid provisions that could stimulate further improvements in access for poor children.