Croix B, Caron KM. Orphan G-Protein Coupled Receptor GPRC5B Is Critical for Lymphatic Development

Numerous studies have focused on the molecular signaling pathways that govern the development and growth of lymphatics in the hopes of elucidating promising druggable targets. G protein-coupled receptors (GPCRs) are currently the largest family of membrane receptors targeted by FDA-approved drugs, but there remain many unexplored receptors, including orphan GPCRs with no known biological ligand or physiological function. Thus, we sought to illuminate the cadre of GPCRs expressed at high levels in lymphatic endothelial cells and identified four orphan receptors: GPRC5B, AGDRF5/GPR116, FZD8 and GPR61. Compared to blood endothelial cells, GPRC5B is the most abundant GPCR expressed in cultured human lymphatic endothelial cells (LECs), and in situ RNAscope shows high mRNA levels in lymphatics of mice. Using genetic engineering approaches in both zebrafish and mice, we characterized the function of GPRC5B in lymphatic development. Morphant gprc5b zebrafish exhibited failure of thoracic duct formation, and Gprc5b^-/- mice suffered from embryonic hydrops fetalis and hemorrhage associated with subcutaneous edema and blood-filled lymphatic vessels. Compared to Gprc5^+/+ littermate controls, Gprc5b^-/- embryos exhibited attenuated developmental lymphangiogenesis. During the postnatal period, ~30% of Gprc5b^-/- mice were growth-restricted or died prior to weaning, with associated attenuation of postnatal cardiac lymphatic growth. In cultured human primary LECs, expression of GPRC5B is required to maintain cell proliferation and viability. Collectively, we identify a novel role for the lymphatic-enriched orphan GPRC5B receptor in lymphangiogenesis of fish, mice and human cells. Elucidating the roles of orphan GPCRs in lymphatics provides new avenues for discovery of druggable targets to treat lymphatic-related conditions such as lymphedema and cancer.

Dermal Lymphatic Capillaries Do Not Obey Murray's Law

Lymphatic vessels serve as a major conduit for the transport of interstitial fluid, immune cells, lipids and drugs. Therefore, increased knowledge about their development and function is relevant to clinical issues ranging from chronic inflammation and edema, to cancer metastasis to targeted drug delivery. Murray's Law is a widely-applied branching rule upheld in diverse circulatory systems including leaf venation, sponge canals, and various human organs for optimal fluid transport. Considering the unique and diverse functions of lymphatic fluid transport, we specifically address the branching of developing lymphatic capillaries, and the flow of lymph through these vessels. Using an empirically-generated dataset from wild type and genetic lymphatic insufficiency mouse models we confirmed that branching blood capillaries consistently follow Murray's Law. However surprisingly, we found that the optimization law for lymphatic vessels follows a different pattern, namely a Murray's Law exponent of ~1.45. In this case, the daughter vessels are smaller relative to the parent than would be predicted by the hypothesized radius-cubed law for impermeable vessels. By implementing a computational fluid dynamics model, we further examined the extent to which the assumptions of Murray's Law were violated. We found that the flow profiles were predominantly parabolic and reasonably followed the assumptions of Murray's Law. These data suggest an alternate hypothesis for optimization of the branching structure of the lymphatic system, which may have bearing on the unique physiological functions of lymphatics compared to the blood vascular system. Thus, it may be the case that the lymphatic branching structure is optimized to enhance lymph mixing, particle exchange, or immune cell transport, which are particularly germane to the use of lymphatics as drug delivery routes.

Lymphatic mimicry in maternal endothelial cells promotes placental spiral artery remodeling

Molecular heterogeneity of endothelial cells underlies their highly specialized functions during changing physiological conditions within diverse vascular beds. For example, placental spiral arteries (SAs) undergo remarkable remodeling to meet the ever-growing demands of the fetus - a process which is deficient in preeclampsia. The extent to which maternal endothelial cells coordinate with immune cells and pregnancy hormones to promote SA remodeling remains largely unknown. Here we found that remodeled SAs expressed the lymphatic markers PROX1, LYVE1, and VEGFR3, mimicking lymphatic identity. Uterine natural killer (uNK) cells, which are required for SA remodeling and secrete VEGFC, were both sufficient and necessary for VEGFR3 activation in vitro and in mice lacking uNK cells, respectively. Using Flt4Chy/+ mice with kinase inactive VEGFR3 and Vegfcfl/fl Vav1-Cre mice, we demonstrated that SA remodeling required VEGFR3 signaling, and that disrupted maternal VEGFR3 signaling contributed to late-gestation fetal growth restriction. Collectively, we identified a novel instance of lymphatic mimicry by which maternal endothelial cells promote SA remodeling, furthering our understanding of the vascular heterogeneity employed for the mitigation of pregnancy complications such as fetal growth restriction and preeclampsia.

Center of pressure metrics derived from spatially registered typically developing data

BACKGROUND

Pedobarography is a commonly used testing procedure in clinical gait analysis, yet has limited roles in quantification for treatment planning, outcome assessment, and classification. Spatial registration between plantar pressure and motion capture data allows for accurate quantitative assessment and metric development based on a typically developing cohort.

RESEARCH QUESTION

This study assesses the validity of new center of pressure based metrics of anatomically registered pedobarography data by evaluating kinematic relationships over a broad spectrum of feet and by evaluating the sensitivity of these metrics to pathologies, interventions, and outcomes in two common clinical foot pathologies.

METHODS

3D trajectories from retroreflective markers were recorded to establish a single foot axis simultaneous with plantar pressure mat data spatially calibrated to a global coordinate system. Indices for clinical populations were determined as mediolateral (MLI, |MLI|, MFI) and anteroposterior (API, |API|) deviations of center of pressure excursions from typically developing feet. 198 feet were retrospectively identified to evaluate relationships between mediolateral (ML) indices and foot kinematics over a spectrum of foot pathologies. Additional feet from two broad pathologic foot types, planovalgus (PV) and cavovarus (CV), were assessed pre and post-surgery to determine sensitivity to pathology, surgical intervention, and outcomes.

RESULTS

ML indices and supination were highly correlated (r² > 0.5). Two mediolateral indices (MLI, MFI) and one anteroposterior index (|API|) demonstrated significant differences between typical and PV feet, with the MFI index also exhibiting significant improvement with surgery. All three mediolateral indices and |API| demonstrated differences between typical and cavovarus feet, with |API| significantly improving with surgery. Changes in API also correlated with patient goals.

SIGNIFICANCE

Spatial registration between plantar pressure center of pressure and motion capture data allows calculation of indices that reflect foot function and are sensitive to foot pathologies and treatment outcomes.

Author Correction: Notch signaling pathway is a potential therapeutic target for extracranial vascular malformations

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Calcitonin-Receptor-Like Receptor Signaling Governs Intestinal Lymphatic Innervation and Lipid Uptake

The absorption of dietary fat requires complex neuroendocrine-mediated regulation of chylomicron trafficking through enterocytes and intestinal lymphatic vessels. Calcitonin-receptor-like receptor (Calcrl) is a G protein-coupled receptor that can bind either a lymphangiogenic ligand adrenomedullin, with coreceptor RAMP2, or the neuropeptide CGRP, with coreceptor RAMP1. The extent to which this common GPCR controls lipid absorption via lymphatics or enteric innervation remains unclear. We used conditional and inducible genetic deletion of Calcrl in lymphatics to elucidate the pathophysiological consequences of this receptor pathway under conditions of high-fat diet. Inefficient absorption of dietary fat coupled with altered lymphatic endothelial junctions in Calcrl ^fl/fl /Prox1-CreER ^T2 mice results in excessive, transcellular lipid accumulation and abnormal enterocyte chylomicron processing and failure to gain weight. Interestingly, Calcrl ^fl/fl /Prox1-CreER ^T2 animals show reduced and disorganized mucosal and submucosal innervation. Consistently, mice with genetic loss of the CGRP coreceptor RAMP1 also displayed mucosal and submucosal innervation deficits, substantiating the CGRP-biased function of Calcrl in the neurolymphocrine axis. Thus, the common Calcrl receptor is a critical regulator of lipid absorption through its cell-specific functions in neurolymphocrine crosstalk.

Notch signaling pathway is a potential therapeutic target for extracranial vascular malformations

Notch expression has been shown to be aberrant in brain arteriovenous malformations (AVM), and targeting Notch has been suggested as an approach to their treatment. It is unclear whether extracranial vascular malformations follow the same patterning and Notch pathway defects. In this study, we examined human extracranial venous (VM) (n = 3), lymphatic (LM) (n = 10), and AV (n = 6) malformations, as well as sporadic brain AVMs (n = 3). In addition to showing that extracranial AVMs demonstrate interrupted elastin and that AVMs and LMs demonstrate abnormal α-smooth muscle actin just as brain AVMS do, our results demonstrate that NOTCH1, 2, 3 and 4 proteins are overexpressed to varying degrees in both the endothelial and mural lining of the malformed vessels in all types of malformations. We further show that two gamma secretase inhibitors (GSIs), DAPT (GSI-IX) and RO4929097, cause dose-dependent inhibition of Notch target gene expression (Hey1) and rate of migration of monolayer cultures of lymphatic endothelial cells (hLECs) and blood endothelial cells (HUVEC). GSIs also inhibit HUVEC network formation. hLECs are more sensitive to GSIs compared to HUVEC. GSIs have been found to be safe in clinical trials in patients with Alzheimer’s disease or cancer. Our results provide further rationale to support testing of Notch inhibitors in patients with extracranial vascular malformations.

hCALCRL mutation causes autosomal recessive nonimmune hydrops fetalis with lymphatic dysplasia

Using genetic, pharmacological and animal model approaches, we elucidate a novel human mutation in a G protein coupled receptor that impairs receptor oligomerization and trafficking leading to fatal, non-immune hydrops fetalis associated with arrested lymphatic development.

We report the first case of nonimmune hydrops fetalis (NIHF) associated with a recessive, in-frame deletion of V205 in the G protein–coupled receptor, Calcitonin Receptor-Like Receptor (hCALCRL). Homozygosity results in fetal demise from hydrops fetalis, while heterozygosity in females is associated with spontaneous miscarriage and subfertility. Using molecular dynamic modeling and in vitro biochemical assays, we show that the hCLR(V205del) mutant results in misfolding of the first extracellular loop, reducing association with its requisite receptor chaperone, receptor activity modifying protein (RAMP), translocation to the plasma membrane and signaling. Using three independent genetic mouse models we establish that the adrenomedullin–CLR–RAMP2 axis is both necessary and sufficient for driving lymphatic vascular proliferation. Genetic ablation of either lymphatic endothelial Calcrl or nonendothelial Ramp2 leads to severe NIHF with embryonic demise and placental pathologies, similar to that observed in humans. Our results highlight a novel candidate gene for human congenital NIHF and provide structure–function insights of this signaling axis for human physiology.

Lymphatic deletion of calcitonin receptor-like receptor exacerbates intestinal inflammation

Lymphatics play a critical role in maintaining gastrointestinal homeostasis and in the absorption of dietary lipids, yet their roles in intestinal inflammation remain elusive. Given the increasing prevalence of inflammatory bowel disease, we investigated whether lymphatic vessels contribute to, or may be causative of, disease progression. We generated a mouse model with temporal and spatial deletion of the key lymphangiogenic receptor for the adrenomedullin peptide, calcitonin receptor-like receptor (Calcrl), and found that the loss of lymphatic Calcrl was sufficient to induce intestinal lymphangiectasia, characterized by dilated lacteals and protein-losing enteropathy. Upon indomethacin challenge, Calcrl^fl/fl/Prox1-CreER^T2 mice demonstrated persistent inflammation and failure to recover and thrive. The epithelium and crypts of Calcrl^fl/fl/Prox1-CreER^T2 mice exhibited exacerbated hallmarks of disease progression, and the lacteals demonstrated an inability to absorb lipids. Furthermore, we identified Calcrl/adrenomedullin signaling as an essential upstream regulator of the Notch pathway, previously shown to be critical for intestinal lacteal maintenance and junctional integrity. In conclusion, lymphatic insufficiency and lymphangiectasia caused by loss of lymphatic Calcrl exacerbates intestinal recovery following mucosal injury and underscores the importance of lymphatic function in promoting recovery from intestinal inflammation.

A comparative perspective on longevity: the effect of body size dominates over ecology in moths

Both physiologically and ecologically based explanations have been proposed to account for among-species differences in lifespan, but they remain poorly tested. Phylogenetically explicit comparative analyses are still scarce and those that exist are biased towards homoeothermic vertebrates. Insect studies can significantly contribute as lifespan can feasibly be measured in a high number of species, and the selective forces that have shaped it may differ largely between species and from those acting on larger animals. We recorded adult lifespan in 98 species of geometrid moths. Phylogenetic comparative analyses were applied to study variation in species-specific values of lifespan and to reveal its ecological and life-history correlates. Among-species and between-gender differences in lifespan were found to be notably limited; there was also no evidence of phylogenetic signal in this trait. Larger moth species were found to live longer, with this result supporting a physiological rather than ecological explanation of this relationship. Species-specific lifespan values could not be explained by traits such as reproductive season and larval diet breadth, strengthening the evidence for the dominance of physiological determinants of longevity over ecological ones.

Docosahexaenoic Acid and Periodontitis in Adults: A Randomized Controlled Trial

Periodontitis is a common chronic inflammatory disease initiated by bacteria, resulting in bone resorption, tooth loss, and systemic inflammation. Long-chain omega-3 fatty acids such as docosahexaenoic acid (DHA) reduce periodontitis in animals. We aimed to determine whether DHA supplementation with low-dose aspirin would reduce periodontitis in humans. We conducted a double-blind placebo-controlled parallel trial lasting 3 mo. Fifty-five adults with moderate periodontitis were randomized to 2,000 mg of DHA or identical soy/corn oil capsules. All participants received 81 mg of aspirin but received no other treatments. We analyzed the primary outcome of per-pocket change in pocket depth using mixed models among teeth with pocket depth ≥5 mm. Secondary outcomes assessed with generalized estimating equations included gingival index, plaque index, and bleeding on probing. Gingival crevicular fluid samples were analyzed for changes in high-sensitivity C-reactive protein (hsCRP) and interleukins 6 and 1β (IL-6 and IL-1β). Plasma was analyzed for changes in systemic inflammatory markers, including hsCRP. We confirmed adherence with erythrocyte fatty acid measurement. Forty-six participants completed the trial. While similar at baseline, the proportion of DHA in red blood cell plasma membranes increased from 3.6% ± 0.9% to 6.2% ± 1.6% in the intervention group but did not change among controls. DHA supplementation decreased mean pocket depth (-0.29 ± 0.13; p = .03) and gingival index (-0.26 ± 0.13; p = .04). Plaque index and bleeding on probing did not change. Significant adjusted differences were found between DHA and control for both gingival crevicular fluid hsCRP (-5.3 ng/mL, standard error [SE] = 2.4, p = .03) and IL-1β (-20.1 pg/mL, SE = 8.2, p = .02) but not IL-6 (0.02 pg/mL, SE = 0.71, p = .98) or systemic hsCRP (-1.19 mg/L, SE = 0.90, p = .20). In this randomized controlled trial, aspirin-triggered DHA supplementation significantly improved periodontal outcomes in people with periodontitis, indicating its potential therapeutic efficacy (clinicaltrials.gov NCT01976806).

The operative correction of symptomatic flat foot deformities in children: the relationship between static alignment and dynamic loading

At our institution surgical correction of symptomatic flat foot deformities in children has been guided by a paradigm in which radiographs and pedobarography are used in the assessment of outcome following treatment. Retrospective review of children with symptomatic flat feet who had undergone surgical correction was performed to assess the outcome and establish the relationship between the static alignment and the dynamic loading of the foot. A total of 17 children (21 feet) were assessed before and after correction of soft-tissue contractures and lateral column lengthening, using standardised radiological and pedobarographic techniques for which normative data were available. We found significantly improved static segmental alignment of the foot, significantly improved mediolateral dimension foot loading, and worsened fore-aft foot loading, following surgical treatment. Only four significant associations were found between radiological measures of static segmental alignment and dynamic loading of the foot. Weakness of the plantar flexors of the ankle was a common post-operative finding. Surgeons should be judicious in the magnitude of lengthening of the plantar flexors that is undertaken and use techniques that minimise subsequent weakening of this muscle group.

BRG1 promotes COUP-TFII expression and venous specification during embryonic vascular development

Arteries and veins acquire distinct molecular identities prior to the onset of embryonic blood circulation, and their specification is crucial for vascular development. The transcription factor COUP-TFII currently functions at the top of a signaling pathway governing venous fate. It promotes venous identity by inhibiting Notch signaling and subsequent arterialization of endothelial cells, yet nothing is known about what regulates COUP-TFII expression in veins. We now report that the chromatin-remodeling enzyme BRG1 promotes COUP-TFII expression in venous endothelial cells during murine embryonic development. Conditional deletion of Brg1 from vascular endothelial cells resulted in downregulated COUP-TFII expression and aberrant expression of arterial markers on veins. BRG1 promotes COUP-TFII expression by binding conserved regulatory elements within the COUP-TFII promoter and remodeling chromatin to make the promoter accessible to transcriptional machinery. This study provides the first description of a factor promoting COUP-TFII expression in vascular endothelium and highlights a novel role for chromatin remodeling in venous specification.

Decreased neuroautonomic complexity in men during an acute major depressive episode: analysis of heart rate dynamics

Major depression affects multiple physiologic systems. Therefore, analysis of signals that reflect integrated function may be useful in probing dynamical changes in this syndrome. Increasing evidence supports the conceptual framework that complex variability is a marker of healthy, adaptive control mechanisms and that dynamical complexity decreases with aging and disease. We tested the hypothesis that heart rate (HR) dynamics in non-medicated, young to middle-aged males during an acute major depressive episode would exhibit lower complexity compared with healthy counterparts. We analyzed HR time series, a neuroautonomically regulated signal, during sleep, using the multiscale entropy method. Our results show that the complexity of the HR dynamics is significantly lower for depressed than for non-depressed subjects for the entire night (P<0.02) and combined sleep stages 1 and 2 (P<0.02). These findings raise the possibility of using the complexity of physiologic signals as the basis of novel dynamical biomarkers of depression.

Clinical gait analysis

Technologies and techniques that have evolved to aid in the assessment of human locomotion and some of the difficulties associated with the clinical application of quantitative gait analysis are examined. The parameters used for the clinical description of gait are outlined, and examples of application of clinical gait analysis are listed. Problems encountered in measuring and assessing gait patterns are discussed. Some commercially available motion measurement systems are described. Future research directions are suggested.

Eusociality and the success of the termites: insights from a supertree of dictyopteran families

Sociality in insects may negatively impact on species richness. We tested whether termites have experienced shifts in diversification rates through time. Supertree methods were used to synthesize family-level relationships within termites, cockroaches and mantids. A deep positive shift in diversification rate is found within termites, but not in the cockroaches from which they evolved. The shift is responsible for most of their extant species richness suggesting that eusociality is not necessarily detrimental to species richness, and may sometimes have a positive effect. Mechanistic studies of speciation and extinction in eusocial insects are advocated.

World Association for the Advancement of Veterinary Parasitology (WAAVP) guidelines for evaluating the effectiveness of anthelmintics in chickens and turkeys

These guidelines have been prepared to assist in the planning, operation and interpretation of studies designed to assess the effectiveness of drugs against helminth parasites of chickens and turkeys. They are the first to be compiled under the auspices of the World Association for the Advancement of Veterinary Parasitology (WAAVP) for these parasites. The advantages and disadvantages of the widely used critical and controlled tests are discussed. Information is provided on the selection of animals for experiments, animal housing, feed, dose determination studies, confirmatory and field trials, record keeping and necropsy procedures. This document should help investigators and those involved in product approval and registration in conducting and evaluating studies concerned with determining the effectiveness and safety of anthelmintic drugs.

Physician-reviewers' perceptions and judgments about quality of care

OBJECTIVE

Although Peer Review Organizations (PROs) and researchers rely on physicians to assess quality of care, little is known about what physicians think about when they judge quality. We sought to identify features of individual cases that are associated with physicians' judgments.

DESIGN

Using 1994 Medicare data, we selected hospitalizations for 1134 beneficiaries in 42 acute care hospitals in California and Connecticut. The sample was enriched with 17 surgical and six medical complications identified using diagnosis and procedure codes. PRO physicians confirmed quality problems using a structured implicit chart review instrument and provided written open-ended comments about each case. We coded physicians' comments for factors presumed to influence judgments about quality.

RESULTS

In crude and adjusted comparisons, reviewers questioned quality more frequently in cases with serious or fatal outcomes, technical mishaps and inadequate documentation. Among surgical (but not medical) patients, they were less likely to record poor quality among patients presenting with an acute illness.

CONCLUSION

Factors other than the adequacy of key processes of care are associated with physician-reviewers' judgments about quality.

Perceptions about complementary therapies relative to conventional therapies among adults who use both: results from a national survey

BACKGROUND

Little is known about perceptions of complementary and alternative medical (CAM) therapy relative to conventional therapy among patients who use both.

OBJECTIVE

To document perceptions about CAM therapies among persons who use CAM and conventional therapies.

DESIGN

Nationally representative, random-household telephone survey.

SETTING

The 48 contiguous U.S. states.

PARTICIPANTS

831 adults who saw a medical doctor and used CAM therapies in 1997.

MEASUREMENTS

Perceptions about helpfulness and patterns of CAM therapy use relative to conventional therapy use and reasons for nondisclosure of CAM therapies.

RESULTS

Of 831 respondents who saw a medical doctor and used CAM therapies in the previous 12 months, 79% perceived the combination to be superior to either one alone. Of 411 respondents who reported seeing both a medical doctor and a CAM provider, 70% typically saw a medical doctor before or concurrent with their visits to a CAM provider; 15% typically saw a CAM provider before seeing a medical doctor. Perceived confidence in CAM providers was not substantially different from confidence in medical doctors. Among the 831 respondents who in the past year had used a CAM therapy and seen a medical doctor, 63% to 72% did not disclose at least one type of CAM therapy to the medical doctor. Among 507 respondents who reported their reasons for nondisclosure of use of 726 alternative therapies, common reasons for nondisclosure were "It wasn't important for the doctor to know" (61%), "The doctor never asked" (60%), "It was none of the doctor's business" (31%), and "The doctor would not understand" (20%). Fewer respondents (14%) thought their doctor would disapprove of or discourage CAM use, and 2% thought their doctor might not continue as their provider. Respondents judged CAM therapies to be more helpful than conventional care for the treatment of headache and neck and back conditions but considered conventional care to be more helpful than CAM therapy for treatment of hypertension.

CONCLUSIONS

National survey data do not support the view that use of CAM therapy in the United States primarily reflects dissatisfaction with conventional care. Adults who use both appear to value both and tend to be less concerned about their medical doctor's disapproval than about their doctor's inability to understand or incorporate CAM therapy use within the context of their medical management.

Long-term trends in the use of complementary and alternative medical therapies in the United States

BACKGROUND

Although recent research has shown that many people in the United States use complementary and alternative medical (CAM) therapies, little is known about time trends in use.

OBJECTIVE

To present data on time trends in CAM therapy use in the United States over the past half-century.

DESIGN

Nationally representative telephone survey of 2055 respondents that obtained information on current use, lifetime use, and age at first use for 20 CAM therapies.

SETTING

The 48 contiguous U.S. states.

PARTICIPANTS

Household residents 18 years of age and older.

MEASUREMENT

Retrospective self-reports of age at first use for each of 20 CAM therapies.

RESULTS

Previously reported analyses of these data showed that more than one third of the U.S. population was currently using CAM therapy in the year of the interview (1997). Subsequent analyses of lifetime use and age at onset showed that 67.6% of respondents had used at least one CAM therapy in their lifetime. Lifetime use steadily increased with age across three age cohorts: Approximately 3 of every 10 respondents in the pre-baby boom cohort, 5 of 10 in the baby boom cohort, and 7 of 10 in the post-baby boom cohort reported using some type of CAM therapy by age 33 years. Of respondents who ever used a CAM therapy, nearly half continued to use many years later. A wide range of individual CAM therapies increased in use over time, and the growth was similar across all major sociodemographic sectors of the study sample.

CONCLUSIONS

Use of CAM therapies by a large proportion of the study sample is the result of a secular trend that began at least a half century ago. This trend suggests a continuing demand for CAM therapies that will affect health care delivery for the foreseeable future.

Use of screening and preventive services among women with disabilities

Roughly 54 million Americans have some disability; at older ages, women are more likely to be disabled than men. Many people with disabilities today live virtually normal life spans, and therefore routine screening and preventive services are essential to their overall quality of care. We used the 1994-1995 National Health Interview Survey (NHIS), with Disability, Family Resources, and Healthy People 2000 supplements, to examine screening and preventive service use for adult women with disabilities living in the community--about 18.4% of women (estimated 18.28 million). Disability was associated with higher age-adjusted rates of: poverty; living alone; low education; inability to work; obesity; and being frequently depressed or anxious. Disabled women generally reported screening and preventive services at rates comparable to all women. Women with major lower extremity mobility difficulties had much lower adjusted odds of Papanicolaou smears (odds ratio, 0.6; 95% confidence interval, 0.4-0.9), mammograms (odds ratio, 0.7; 95% confidence interval, 0.5-0.9), and smoking queries (odds ratio, 0.6; 95% confidence interval, 0.5-0.8). Various approaches exist to improve access for disabled women to health care services.

Are aggressive treatment strategies less cost-effective for older patients? The case of ventilator support and aggressive care for patients with acute respiratory failure

OBJECTIVES

A common assumption is that life-sustaining treatments are much less cost-effective for older patients than for younger patients. We estimated the incremental cost-effectiveness of providing mechanical ventilation and intensive care for patients of various ages who had acute respiratory failure.

DESIGN

Retrospective analysis of data on acute respiratory failure from Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT).

SETTING

Acute hospital.

PARTICIPANTS

1,005 with acute respiratory failure; 963 received ventilator support and 42 had ventilator support withheld.

MEASUREMENTS

We studied 1,005 patients enrolled in a five-center study of seriously ill patients (SUPPORT) with acute respiratory failure (pneumonia or acute respiratory distress syndrome and an Acute Physiology Score > or = 10) requiring ventilator support. For cost-effectiveness analyses, we estimated life expectancy based on long-term follow-up of SUPPORT patients and estimated utilities (quality-of-life weights) using time-tradeoff questions. We used hospital fiscal data and Medicare data to estimate healthcare costs. We divided patients into three age groups (< 65, 65-74, and > or = 75 years); for each age group, we performed separate analyses for patients with a < or = 50% probability of surviving at least 2 months (high-risk group) and those with a > 50% probability of surviving at least 2 months (low-risk group).

RESULTS

Of the 963 patients who received ventilator support, 44% were female; 48% survived 6 months; and the median (25th, 75th percentile) age was 63 (46, 75) years. For the 42 patients for whom ventilator support was withheld, the median survival was 3 days. For low-risk patients (> 50% estimated 2-month survival), the incremental cost (1998 dollars) per quality-adjusted life-year (QALY) saved by providing ventilator support and aggressive care increased across the three age groups ($32,000 for patients age < 65, $44,000 for those age 65-74, and $46,000 for those age > or = 75). For high-risk patients, the incremental cost-effectiveness was much less favorable and was least favorable for younger patients ($130,000 for patients age < 65, $100,000 for those age 65-74, and $96,000 for those age > or = 75). When we varied our assumptions from 50% to 200% of our baseline estimates in sensitivity analyses, results were most sensitive to the costs of the index hospitalization.

CONCLUSIONS

For patients with relatively good short-term prognoses, we found that ventilator support and aggressive care were economically worthwhile, even for patients 75 years and older. For patients with poor short-term prognoses, ventilator support and aggressive care were much less cost-effective for adults of all ages.

Perceptions of human immunodeficiency virus and sexually transmitted disease risk among low-income adults: a pilot study

Sexual risk-taking research and subsequent intervention programs have focused almost exclusively on adolescents and men who have sex with men. In comparison, less research has been conducted into adult heterosexual risk-taking behavior. The purposes of this pilot study were to test a survey instrument, assess how low-income adults perceive their risk of human immunodeficiency virus (HIV) and sexually transmitted disease (STD) infection, and determine the degree to which condom use is a function of age. The Health Belief Model was used to guide the development of the survey instrument. In the Health Belief Model, age is a mediating factor that influences a person's likelihood to take action to change his or her lifestyle. Respondents perceived that their vulnerability to infection declined because of increased age and decreased frequency of coitus. Condom use was found to significantly decline as the age of the respondents increased. Although this is only a pilot study, the findings highlight the need for HIV and STD education for all age groups and genders.

Mobility difficulties are not only a problem of old age

BACKGROUND

Lower extremity mobility difficulties often result from common medical conditions and can disrupt both physical and emotional well-being.

OBJECTIVES

To assess the national prevalence of mobility difficulties among noninstitutionalized adults and to examine associations with demographic characteristics and other physical and mental health problems.

DESIGN

Cross-sectional survey using the 1994-1995 National Health Interview Survey-Disability Supplement (NHIS-D). We constructed measures of minor, moderate, and major lower extremity mobility difficulties using questions about ability to walk, climb stairs, and stand, and use of mobility aids (e.g., canes, wheelchairs). Age and gender adjustment used direct standardization methods in Software for the Statistical Analysis of Correlated Data (SUDAAN).

PARTICIPANTS

Noninstitutionalized, civilian U.S. residents aged 18 years and older. National Health Interview Survey sampling weights with SUDAAN provided nationally representative population estimates.

RESULTS

An estimated 19 million people (10.1%) reported some mobility difficulty. The mean age of those with minor, moderate, or major difficulty ranged from 59 to 67 years. Of those reporting major difficulties, 32% said their problems began at aged 50 years or younger. Adjusted problem rates were higher among women (11.8%) than men (8.8%), and higher among African American (15.0%) than whites (10.0%). Persons with mobility difficulties were more likely to be poorly educated, living alone, impoverished, obese, and having problems conducting daily activities. Among persons with major mobility difficulties, 30.6% reported being frequently depressed or anxious, compared to 3.8% for persons without mobility difficulties.

CONCLUSIONS

Reports of mobility difficulties are common, including among middle-aged adults. Associations with poor performance of daily activities, depression, anxiety, and poverty highlight the need for comprehensive care for persons with mobility problems.

An evaluation of the posterior leaf spring orthosis using joint kinematics and kinetics

The primary function of the posterior leaf spring orthosis (PLS) is to prevent excessive equinus or drop foot in swing. The name of the orthosis, posterior leaf "spring," suggests that it also mechanically augments push-off in stance. The purpose of this study was to determine the effect of the PLS on ankle function by using computerized gait-analysis techniques. Multiple barefoot versus brace walks were compared in 31 children with cerebral palsy. Results indicate that the PLS reduces excessive equinus in swing and is sufficiently flexible to allow ankle dorsiflexion in midstance. In terminal stance, the peak power-generating capabilities of the ankle were reduced when the child was wearing the PLS. Energy results indicate that more mechanical energy was absorbed during midstance and less produced during terminal stance with the PLS. Therefore, the PLS improved ankle function but did not augment ankle function through storage and return of mechanical, or spring, energy.