Fine particulate matter composition in American Indian vs. Non-American Indian communities

BACKGROUND

Fine particulate matter (PM2.5) exposure is a known risk factor for numerous adverse health outcomes, with varying estimates of component-specific effects. Populations with compromised health conditions such as diabetes can be more sensitive to the health impacts of air pollution exposure. Recent trends in PM2.5 in primarily American Indian- (AI-) populated areas examined in previous work declined more gradually compared to the declines observed in the rest of the US. To further investigate components contributing to these findings, we compared trends in concentrations of six PM2.5 components in AI- vs. non-AI-populated counties over time (2000-2017) in the contiguous US.

METHODS

We implemented component-specific linear mixed models to estimate differences in annual county-level concentrations of sulfate, nitrate, ammonium, organic matter, black carbon, and mineral dust from well-validated surface PM2.5 models in AI- vs. non-AI-populated counties, using a multi-criteria approach to classify counties as AI- or non-AI-populated. Models adjusted for population density and median household income. We included interaction terms with calendar year to estimate whether concentration differences in AI- vs. non-AI-populated counties varied over time.

RESULTS

Our final analysis included 3108 counties, with 199 (6.4%) classified as AI-populated. On average across the study period, adjusted concentrations of all six PM2.5 components in AI-populated counties were significantly lower than in non-AI-populated counties. However, component-specific levels in AI- vs. non-AI-populated counties varied over time: sulfate and ammonium levels were significantly lower in AI- vs. non-AI-populated counties before 2011 but higher after 2011 and nitrate levels were consistently lower in AI-populated counties.

CONCLUSIONS

This study indicates time trend differences of specific components by AI-populated county type. Notably, decreases in sulfate and ammonium may contribute to steeper declines in total PM2.5 in non-AI vs. AI-populated counties. These findings provide potential directives for additional monitoring and regulations of key emissions sources impacting tribal lands.

Toxic metal mixtures in private well water and increased risk for preterm birth in North Carolina

BACKGROUND

Prenatal exposure to metals in private well water may increase the risk of preterm birth (PTB) (delivery < 37 weeks' gestation). In this study, we estimated associations between arsenic, manganese, lead, cadmium, chromium, copper, and zinc concentrations in private well water and PTB incidence in North Carolina (NC).

METHODS

Birth certificates from 2003-2015 (n = 1,329,071) were obtained and pregnancies were assigned exposure using the mean concentration and the percentage of tests above the maximum contaminant level (MCL) for the census tract of each individuals' residence at the time of delivery using the NCWELL database (117,960 well water tests from 1998-2019). We evaluated associations between single metals and PTB using adjusted logistic regression models. Metals mixtures were assessed using quantile-based g-computation.

RESULTS

Compared with those in other census tracts, individuals residing in tracts where > 25% of tests exceeded the MCL for lead (aOR 1.10, 95%CI 1.02,1.18) or cadmium (aOR 1.11, 95% CI 1.00,1.23) had an increased odds of PTB. Conversely, those residing in areas with > 25% MCL for zinc (aOR 0.77 (95% CI: 0.56,1.02) and copper (aOR 0.53 (95% CI: 0.13,1.34)) had a reduced odds of PTB. A quartile increase in the concentrations of a mixture of lead, cadmium, and chromium was associated with a small increased odds for PTB (aOR 1.02, 95% CI 1.01, 1.03). This metal mixture effect was most pronounced among American Indian individuals (aOR per quartile increase in all metals: 1.19 (95% CI 1.06,1.34)).

CONCLUSIONS

In a large study population of over one million births, lead and cadmium were found to increase the risk of PTB individually and in a mixture, with additional mixtures-related impacts estimated from co-exposure with chromium. This study highlights critical racial and ethnic health disparities in relation to private well water thereby emphasizing the urgent need for improved private well water quality to protect vulnerable populations.

Stereotactic Radiosurgery (SRS) for Large Brain Metastases: Dosimetric and Clinical Predictors of Local Progression and Radionecrosis

PURPOSE/OBJECTIVE(S)

Stereotactic radiosurgery (SRS) provides high rates of local control for small brain metastases with low rates of radionecrosis (RN). Larger targets are associated with increased risk of both local progression (LP) and RN. In this analysis, we hypothesized that dosimetric and clinical parameters predict for risk of LP and RN in SRS targets larger than two centimeters.

MATERIALS/METHODS

We retrospectively reviewed patients with one or more targets with either an intact versus post-operative cavity larger than 2.0 cm treated with LINAC-based SRS between 2017 and 2022 at one institution. We assessed for association between patient, treatment, and disease variables with LP and RN. Variables assessed included tumor resection status, PDL1 positivity, target volume, maximum and minimum target dose, EQD2 and BED (a/b = 2 for necrosis and a/b = 10 for tumor control), as well as receipt of steroids, bevacizumab, or systemic therapy before or after SRS. Radionecrosis was determined by characteristic radiographic changes. Analyses were performed for the entire cohort and within subsets including by resection status and dose fractionation.

RESULTS

A total of 178 lesions in 143 patients were included. Targets with volume diameters measuring at least 2 cm were used. Median follow-up was 2.3 years. Overall survival at 1 and 2 years was 56% and 32%, respectively. Most lesions (n = 119) were resected and treated with SRS post-operatively. The most common dose and fractionation schemes used were 30 Gy in 5 fractions (n = 89) and 27 Gy in 3 fractions (n = 63). For the entire cohort, the cumulative incidence of LP 1 and 2 years was 26% and 34%, respectively. The cumulative incidence of radiographic radionecrosis at 1 and 2 years was 12% and 17%, respectively. There was no difference in LP or RN between 27 Gy in 3 fractions versus 30 Gy in 5 fractions (p>0.5 for both). Median planning target volume (PTV) size was 18.5 cc for the 27 Gy in 3 fraction group compared to 21.9 cc in the 30 Gy in 5 fraction group. Minimum or maximum dose within the target was not associated with increased risk of LP or RN. Among patients receiving 27 Gy in 3 fractions, patients treated with resection followed by SRS had lower risk of LP compared to those treated with SRS alone (HR: 0.15, 95% CI: 0.03-0.64, p = 0.011). Among patients receiving 30 Gy in 5 fractions, patients who received corticosteroids prior to SRS had a lower risk of RN (HR: 0.14, 95% CI: 0.03-0.66, p = 0.013). For the entire cohort as well as within all subgroups, PD-L1≥1% was associated with increased risk of RN (p<0.001 for all).

CONCLUSION

Selecting the optimal SRS dose fractionation and planning parameters to minimize both LP and RN remains a challenge for large targets. In this analysis, 27 Gy in 3 fractions appeared to provide equivalent LP and RN compared to 30 Gy in 5 fractions, and may be more convenient for patients. Patients with PD-L1≥1% with large brain targets treated with SRS may be at increased risk of RN; corticosteroid prophylaxis may be considered in this population.

Inequalities in cesarean births between American Indian & Alaska Native people and White people

OBJECTIVE

To explore population-level American Indian & Alaska Native-White inequalities in cesarean birth incidence after accounting for differences in cesarean indication, age, and other individual-level risk factors.

DATA SOURCES AND STUDY SETTING

We used birth certificate data inclusive of all live births within the United States between January 1 and December 31, 2017.

STUDY DESIGN

We calculated propensity score weights that simultaneously incorporate age, cesarean indication, and clinical and obstetric risk factors to estimate the American Indian and Alaska Native-White inequality.

DATA COLLECTION/EXTRACTION METHODS

Births to individuals identified as American Indian, Alaska Native, or White, and residing in one of the 50 US states or the District of Columbia were included. Births were excluded if missing maternal race/ethnicity or any other covariate.

PRINCIPAL FINDINGS

After weighing the American Indian and Alaska Native obstetric population to be comparable to the distribution of cesarean indication, age, and clinical and obstetric risk factors of the White population, the cesarean incidence among American Indian and Alaska Natives increased to 33.4% (95% CI: 32.0-34.8), 3.2 percentage points (95% CI: 1.8-4.7) higher than the observed White incidence. After adjustment, cesarean birth incidence remained higher and increased in magnitude among American Indian and Alaska Natives in Robson groups 1 (low risk, primary), 6 (nulliparous, breech presentation), and 9 (transverse/oblique lie).

CONCLUSIONS

The unadjusted lower cesarean birth incidence observed among American Indian and Alaska Native individuals compared to White individuals may be related to their younger mean age at birth. After adjusting for this demographic difference, we demonstrate that American Indian and Alaska Native individuals undergo cesarean birth more frequently than White individuals with similar risk profiles, particularly within the low-risk Robson group 1 and those with non-cephalic presentations (Robson groups 6 and 9). Racism and bias in clinical decision making, structural racism, colonialism, or other unidentified factors may contribute to this inequality.

Factor analysis of the Center for Epidemiological Studies Depression Scale in American Indian women

The Center for Epidemiological Studies Depression Scale (CES-D) is widely used to assess depressive symptoms in the general population. It lacks validation for widespread use within the American Indian population, however. To address this gap, we explored and confirmed the factor structure of the CES-D among a community sample of southeastern American Indian women. We analyzed data from a sample of 150 American Indian women ages 18-50 from a southeastern tribe who had complete responses on the CES-D as part of a larger cross-sectional, community-engaged study. We performed exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) to assess the measure's validity. We examined EFA models ranging from one to five factors, with the four-factor structure yielding the best overall model fit (CFI = 1.00, TLI = 0.99, RMSEA = 0.03). Differences between the four-factor EFA-retained structure from our sample and Radloff's four-factor structure emerged. Only the interpersonal factor was common to both factor structures. Our study findings confirm the validity of the original four-factor structure of the CES-D for younger adult American Indian women in the southeast. Contrasting findings with the EFA-retained structure, however, provide a more nuanced interpretation of our results.

Methodological Considerations in Scale Refinement with Diverse Populations: A Case Example Using the CES-D with a Community Sample of American Indian Women

Although many psychometric assessments are used extensively in population-based research to determine psychopathology, these tools have not been thoroughly validated or appropriately adapted for use in diverse populations. Indeed, depression measurement studies among American Indian and female populations are scarce, omitting key opportunities to tailor psychological measurement for this population. To build psychometric evidence of measures in this population, we used a procedural method to examine a standard psychological instrument-the Center for Epidemiological Studies Depression Scale (CES-D)-with a community sample of southeast American Indian women. Our results showed strong psychometric reliability of the 20-item CES-D. The "effort" item presented diminished validity, as demonstrated by a negative counter-intuitive item-to-total correlation (ITC) value. Dropping the "effort" item resulted in a 19-item scale with a better fit in the within-group examination of community-based American Indian women. Compared to the 20-item CES-D scale, the revised 19-item measure ("effort" item removed) resulted in minimal changes to women's depression categories. However, we did detect patterns in shifts such that the 19-item scale generally underestimated (i.e., placed women in a lower category) depressive symptoms compared to the 20-item scale. Depending on their study goals, researchers engaging in population-based research should carefully weigh the use of original scales that allow for consistency in reporting with refined scales that fit psychometrically. We present the outlined method as a tool that expands on current approaches in scale refinement, and aids researchers in making more informed decisions regarding refined scales with diverse populations.

Air Pollution in American Indian Versus Non-American Indian Communities, 2000-2018

Objectives. To compare fine particulate matter (PM2.5) concentrations in American Indian (AI)-populated with those in non-AI-populated counties over time (2000-2018) in the contiguous United States. Methods. We used a multicriteria approach to classify counties as AI- or non--AI-populated. We ran linear mixed effects models to estimate the difference in countywide annual PM2.5 concentrations from well-validated prediction models and monitoring sites (modeled and measured PM2.5, respectively) in AI- versus non-AI-populated counties. Results. On average, adjusted modeled PM2.5 concentrations in AI-populated counties were 0.38 micrograms per cubic meter (95% confidence interval [CI] = 0.23, 0.54) lower than in non-AI-populated counties. However, this difference was not constant over time: in 2000, modeled concentrations in AI-populated counties were 1.46 micrograms per cubic meter (95% CI = 1.25, 1.68) lower, and by 2018, they were 0.66 micrograms per cubic meter (95% CI = 0.45, 0.87) higher. Over the study period, adjusted modeled PM2.5 mean concentrations decreased by 2.13 micrograms per cubic meter in AI-populated counties versus 4.26 micrograms per cubic meter in non-AI-populated counties. Results were similar for measured PM2.5. Conclusions. This study highlights disparities in PM2.5 trends between AI- and non-AI-populated counties over time, underscoring the need to strengthen air pollution regulations and prevention implementation in tribal territories and areas where AI populations live. (Am J Public Health. 2022;112(4): 615-623. https://doi.org/10.2105/AJPH.2021.306650).

Exploring a broader context of the home environment and its relationship with asthma control in American Indian children

In this cross-sectional study of 60 American Indian mother-child dyads from Southeastern North Carolina, we examined whether childhood asthma control was related to household-level factors, such as environmental tobacco smoke and family management behaviors. We also examined the relationships among family management behaviors and maternal depressive symptoms. We used logistic regression to assess the relationships among childhood asthma control, the presence of environmental tobacco smoke, and family management behaviors, specifically condition management ability (CMA) and condition management effort (CME). We used linear regression to evaluate the relationships between both CMA and CME and maternal depressive symptoms. Better asthma control in children was associated with the absence of environmental tobacco smoke in the home and the maternal perception of asthma as a manageable condition. Mothers perceived an increase in effort to manage their child's asthma as their depressive symptoms increased. These findings emphasize the importance of environmental triggers, perceptions of condition management, and maternal mental health in controlling asthma in American Indian children. Interventions to reduce environmental triggers, treat maternal depressive symptoms, and support mothers in their ability to manage childhood asthma may yield better asthma control and help to reduce existing racial disparities in this population.

A community-engaged approach to investigate cardiovascular-associated inflammation among American Indian women: A research protocol

American Indian women are more likely to die from cardiovascular disease (CVD) than White or African American women. Inflammatory processes may underlie CVD disparities by gender and race and may be critical to understanding population-specific drivers and potential buffers. Exposure to environmental air pollutants, especially particulate matter (PM), is known to be an important catalyst in CVD-associated inflammation. Positive psychological states, associated with low levels of inflammatory gene expression, could serve to moderate the inflammatory response to environmental air pollutants and ultimately lead to better cardiovascular health outcomes. The aim of the ongoing community-engaged and NIH-funded study described in this study protocol is to address the racial and gender gaps in CVD mortality by investigating the contextually relevant and culturally important determinants of health among American Indian women. In this paper we describe the procedures used to examine the relationship between environmental air pollutant exposures (PM_10-2.5 and PM _2.5 ), psychological factors (e.g., depressive symptoms, posttraumatic stress symptoms, eudemonic well-being, and positive emotions), and cardiovascular-associated inflammation (hs-CRP, IL-6, Amyloid A, CBCs with differentials) in a sample of 150 women 18-50 years of age from the Lumbee Tribe in southeastern North Carolina. We describe lessons learned and strategies used in developing a community-engaged approach to enhance recruitment of American Indian women in biomedical research. The empirical data and community infrastructure resulting from this study will be foundational in designing and testing future interventions to reduce CVD-associated morbidity and mortality in American Indian women.

Contraceptive Use Among Women with Prediabetes and Diabetes in a US National Sample

INTRODUCTION

Although elevated blood glucose is associated with adverse maternal and fetal health outcomes, evidence suggests that women with diabetes may not be receiving comprehensive reproductive health care, including family planning and preconception care. Using a population-based sample, we evaluated the relationship between contraceptive use and biomarker-identified diabetes.

METHODS

This cross-sectional study used data from 5548 women in the nationally representative National Longitudinal Study of Adolescent to Adult Health (Add Health) from 2007 to 2009. Women were aged 24 to 32 years, sexually active with men, and not pregnant. Hemoglobin A1C identified prediabetes and diabetes from blood specimens. The primary outcome was most effective contraception used in the past year: more effective (sterilization, intrauterine device, implant, combined hormonal methods, or injectable), less effective (condoms, diaphragms, spermicides, natural family planning, or withdrawal), or none. Multinomial regression models were adjusted for race and ethnicity, education, insurance, health care access, and body mass index.

RESULTS

Of the women with diabetes, 37.6% used more effective contraception, 33.6% less effective contraception, and 28.8% none. Women with diabetes had higher odds of using no contraception, rather than more effective contraception, than women with normoglycemia (adjusted odds ratio [aOR], 1.90; 95% CI, 1.25-2.87). Women with diabetes who were undiagnosed had greater odds of using less effective contraception, rather than more effective contraception, compared with those who were diagnosed (aOR 3.39; 95% CI, 1.44-7.96). Contraceptive use did not differ between women with prediabetes and normoglycemia.

DISCUSSION

Less effective contraceptive methods were commonly used by women with diabetes. Midwives and other women's health care providers can support women with diabetes to reach their pregnancy goals by providing preconception care and family planning.

Racial/Ethnic Disparities in Diabetes Diagnosis and Glycemic Control Among Women of Reproductive Age

BACKGROUND

Types 1 and 2 diabetes mellitus complicate pregnancies and threaten the health of women of reproductive age and their children. Among older adults, diabetes morbidity disproportionately burdens racial/ethnic minorities, but diabetes emergence among younger adults has not been as well characterized. The objective of this study was to describe the distribution of diagnosed diabetes, undiagnosed diabetes, suboptimal preconception glycemic control, and prediabetes among women of reproductive age across racial/ethnic backgrounds.

MATERIALS AND METHODS

We analyzed data collected in 2007-2008 from 6774 nonpregnant women, ages 24-32, in the National Longitudinal Study of Adolescent to Adult Health (Add Health). Prediabetes and undiagnosed diabetes were identified by fasting glucose and glycosylated hemoglobin (A1C) and diagnosed diabetes by self-report or antihyperglycemic medication use. We used multinomial regression models to predict prediabetes or diabetes versus normoglycemia. Within women with diabetes, we used logistic regression to predict those being undiagnosed and having suboptimal preconception glycemic control based on A1C.

RESULTS

The estimated prevalence of diabetes was 6.8%, of which 45.3% was undiagnosed. Diabetes prevalence varied by race/ethnicity (p < 0.001): 15.0% of non-Hispanic black women (75.6% undiagnosed), 7.5% of Hispanic women (48.1% undiagnosed), 4.8% of non-Hispanic white women (22.8% undiagnosed), and 4.5% of Asian women (11.4% undiagnosed). The prevalence of prediabetes was highest in non-Hispanic black (38.5%), followed by Hispanic (27.8%), Asian (25.1%), Native American (20.3%), and non-Hispanic white (16.6%) women.

CONCLUSIONS

Racial/ethnic disparities exist among women of reproductive age with prediabetes and diabetes. Meeting their healthcare needs requires addressing health inequities and coordination of diabetes management with reproductive health.

Reducing Cardiovascular Disparities Through Community-Engaged Implementation Research: A National Heart, Lung, and Blood Institute Workshop Report

Cardiovascular disparities remain pervasive in the United States. Unequal disease burden is evident among population groups based on sex, race, ethnicity, socioeconomic status, educational attainment, nativity, or geography. Despite the significant declines in cardiovascular disease mortality rates in all demographic groups during the last 50 years, large disparities remain by sex, race, ethnicity, and geography. Recent data from modeling studies, linked micromap plots, and small-area analyses also demonstrate prominent variation in cardiovascular disease mortality rates across states and counties, with an especially high disease burden in the southeastern United States and Appalachia. Despite these continued disparities, few large-scale intervention studies have been conducted in these high-burden populations to examine the feasibility of reducing or eliminating cardiovascular disparities. To address this challenge, on June 22 and 23, 2017, the National Heart, Lung, and Blood Institute convened experts from a broad range of biomedical, behavioral, environmental, implementation, and social science backgrounds to summarize the current state of knowledge of cardiovascular disease disparities and propose intervention strategies aligned with the National Heart, Lung, and Blood Institute mission. This report presents the themes, challenges, opportunities, available resources, and recommended actions discussed at the workshop.

Use of Fish Telemetry in Rehabilitation Planning, Management, and Monitoring in Areas of Concern in the Laurentian Great Lakes

Freshwater ecosystems provide many ecosystem services; however, they are often degraded as a result of human activity. To address ecosystem degradation in the Laurentian Great Lakes, Canada and the United States of America established the Great Lakes Water Quality Agreement (GLWQA). In 1987, 43 highly polluted and impacted areas were identified under the GLWQA as having one or more of 14 Beneficial Use Impairments (BUIs) to the physical and chemical habitat for fish, wildlife and humans, and were designated as Areas of Concern (AOC). Subnational jurisdictions combined with local stakeholders, with support from federal governments, developed plans to remediate and restore these sites. Biotelemetry (the tracking of animals using electronic tags) provides information on the spatial ecology of fish in the wild relevant to habitat management and stock assessment. Here, seven case studies are presented where biotelemetry data were directly incorporated within the AOC Remedial Action Plan (RAP) process. Specific applications include determining seasonal fish-habitat associations to inform habitat restoration plans, identifying the distribution of pollutant-indicator species to identify exposure risk to contamination sources, informing the development of fish passage facilities to enable fish to access fragmented upstream habitats, and assessing fish use of created or restored habitats. With growing capacity for fish biotelemetry research in the Great Lakes, we discuss the strengths and weaknesses of incorporating biotelemetry into AOC RAP processes to improve the science and practice of restoration and to facilitate the delisting of AOCs.

Guidelines for research recruitment of underserved populations (EERC)

PURPOSE

Despite concerted efforts to establish health equity, significant disparities persist. One roadblock to eliminating health disparities is the inadequate recruitment of underserved populations, which prevents researchers from creating culturally-tailored interventions. To further develop the science of recruitment, we argue that a systematic approach should be applied to research participant recruitment. Given the lack of practical and comprehensive recruitment conceptual frameworks or guidelines in the literature, the authors propose newly synthesized guidelines for research recruitment of underserved populations: EERC (evaluate, engage, reflect, and carefully match).

METHODS

The EERC guidelines are delineated, and the application of these guidelines is illustrated through a study recently conducted by the authors.

RESULTS

The guidelines consist of the following four components: 1. Evaluate the composition of the research team; 2. Engage fully with the community by working with key informants and cultural insiders; 3. Reflect the unique cultural characteristics of the community in the research conduct; and 4. Carefully use a matching technique. The application component of the article demonstrates concrete examples of how the guidelines can enhance research recruitment for an underserved population.

CONCLUSION

The authors intend these guidelines to be broadly applicable for research teams regardless of research design or characteristics of the underserved population. Application of these guidelines in nursing and health science will contribute to increasing research recruitment of underserved populations, with the goal of reducing health disparities and achieving health equity for all persons.

Using genetic inference to re-evaluate the minimum longevity of the lemon shark Negaprion brevirostris

A combination of mark-recapture and genetic sampling was used to extend the minimum longevity of an elasmobranch species and the life span estimate of the lemon shark Negaprion brevirostris was increased conservatively from 20·2 to 37 years. This increase in longevity means higher vulnerability and a longer recovery time from exploitation.

Birthing and Parenting a Premature Infant in a Cultural Context

The purpose of this longitudinal qualitative descriptive study was to explore American Indian mothers' perceptions of parenting their premature infants over their first year of life in the context of their culture, including the birth and hospitalization experience. A convenience sample of 17 American Indian mothers and their premature infants were recruited from either a neonatal intensive care unit (NICU) or pediatric clinic in the southeast. Semistructured interviews were conducted at two time points. Through content analytic methods, three broad categories were revealed: descriptions of having a premature infant in the NICU, descriptions of parenting a premature infant, and the influence of Lumbee culture on parenting a premature infant. Certain aspects of American Indian culture appear to be important in having a premature infant in the NICU and in parenting a premature infant. We recommend that health care providers deliver culturally appropriate care that fully supports American Indian mothers and their premature infants.

Interactive behaviors of American Indian mothers and their premature infants

The interactive behaviors of 17 American Indian mothers and their premature infants and selected maternal and infant factors affecting those behaviors were measured using naturalistic observation and the Home Observation for Measurement of the Environment (HOME) Inventory at 3, 6, and 12 months corrected infant age. The frequency of some maternal behaviors changed over the first 12 months. Mothers spent less time holding, looking at, touching, and interacting with their premature infants and more time uninvolved as the infant aged. Maternal education and infant illness severity were associated with mother-infant interactive behaviors and HOME Inventory scores. These findings emphasize the importance of maternal and infant factors affecting the interactions between American Indian premature infants and their mothers.

Interactive behaviors of ethnic minority mothers and their premature infants

OBJECTIVE

To compare the interactive behaviors of American Indian mothers and their premature infants with those of African American mothers and their premature infants.

DESIGN

Descriptive, comparative study.

SETTING

Three neonatal intensive care units and two pediatric clinics in the southeast.

PARTICIPANTS

Seventy-seven mother/infant dyads: 17 American Indian mother/infant dyads and 60 African American mother/infant dyads.

METHODS

Videotapes of mother/infant interactions and the Home Observation for Measurement of the Environment (HOME) were used to assess the interactions of the mothers and their premature infants at 6 months corrected age.

RESULTS

American Indian mothers looked more, gestured more, and were more often the primary caregivers to their infants than the African American mothers. American Indian infants expressed more positive affect and gestured more to their mothers, whereas African American infants engaged in more non-negative vocalization toward their mothers. African American mothers scored higher on the HOME subscales of provision of appropriate play materials and parental involvement with the infant. American Indian mothers scored higher on the opportunities for variety in daily living subscale.

CONCLUSION

Although many of the interactive behaviors of American Indian and African American mother/infant dyads were similar, some differences did occur. Clinicians need to be aware of the cultural differences in mother/infant interactions. To optimize child developmental outcomes, nurses need to support mothers in their continuation or adoption of positive interactive behaviors.

Dietary triggers in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a frequently occurring, benign functional gastrointestinal disorder with a complex poorly understood pathology which appears to be multifactorial in nature. There is no association with structural or biochemical abnormalities in the gastrointestinal tract. Functional variations in myoelectrical activity, visceral hypersensitivity and illness behaviours have all been observed in patients experimentally. In conjunction with environmental, psychological and alimentary factors, these mechanisms have been proposed as the major determinants of symptom genesis. Certainly, dietary factors are frequently perceived by sufferers as powerful symptom triggers, with many reporting multiple food intolerance. Physicians, however, remain divided upon the relevance of food to the disorder, with many eschewing a nutritional connection. This is unsurprising as, despite much experimental work to determine the clinical relevance of food intolerance and allergy to the aetiology of the disorder, the vast range of foodstuffs available for testing, inherent procedural problems with test foods, methodological insufficiencies and the continually evolving knowledge of the disorder, particularly the subgrouping of sufferers, have restricted the scientific validity of current findings. At the present time, it is difficult to make informed judgement upon the importance of food in IBS, and rigorously designed, large scale trials devised in the light of recent knowledge are required before conclusions can be drawn.

Exploring modifiable risk factors for wheezing in African American premature infants

OBJECTIVE

To examine the degree to which obesity during infancy, consistent exposure to secondhand smoke, and parenting (positive attention, maternal involvement, and negative control) were related to early development of wheezing in a cohort of African American premature infants at 2, 6, 12, 18, and 24 months corrected age.

DESIGN

Secondary analysis of a subset of variables from a larger nursing support intervention study.

SETTING

Two regional perinatal centers in the southeastern United States.

PARTICIPANTS

One hundred and sixty-eight African American premature infants (70 boys, 98 girls) who weighed less than 1,750 g or required mechanical ventilation and their mothers.

METHODS

The presence of wheezing was obtained from maternal report at 2, 6, 12, 18, and 24 months. Infants were considered to have medically significant wheezing if they were using bronchodilators or pulmonary anti-inflammatory medications.

RESULTS

The percentage of infants who had medically significant wheezing increased from 12% at 2 months to 24% at 24 months corrected age. Infants who received more positive attention from their mothers had a slightly higher increase in the probability of developing wheezing over time. Infants of mothers who received public assistance had an increased probability of wheezing. Consistent exposure to secondhand smoke, obesity during infancy, maternal negative control, and maternal involvement were not related to the development of wheezing.

CONCLUSION

These findings suggest that the likelihood of developing wheezing in African American premature infants is associated with receiving more positive attention from their mothers and having mothers who receive public assistance. Because modifiable risk factors were not highly related to wheezing, intervention efforts need to focus on early identification and treatment of wheezing and asthma-related symptoms.

Psychogenic non-epileptic seizures--definition, etiology, treatment and prognostic issues: a critical review

In this review we systematically assess our currently available knowledge about psychogenic non-epileptic seizures (PNES) with an emphasis on the psychological mechanisms that underlie PNES, possibilities for psychological treatment as well as prognosis. Relevant studies were identified by searching the electronic databases. Case reports were not considered. 93 papers were identified; 65 of which were studies. An open non-randomized design, comparing patients with PNES to patients with epilepsy is the dominant design. A working definition for PNES is proposed. With respect to psychological etiology, a heterogeneous set of factors have been identified. Not all factors have a similar impact, though. On the basis of this review we propose a model with several factors that may interact in both the development and prolongation of PNES. These factors involve psychological etiology, vulnerability, shaping, as well as triggering and prolongation factors. A necessary first step of intervention in patients with PNES seems to be explaining the diagnosis with care. Although the evidence for the efficacy of additional treatment strategies is limited, variants of cognitive (behavioural) therapy showed to be the preferred type of treatment for most patients. The exact choice of treatment should be based on individual differences in the underlying factors. Outcome can be measured in terms of seizure occurrence (frequency, severity), but other measures might be of greater importance for the patient. Prognosis is unclear but studies consistently report that 1/3rd to 1/4th of the patients become chronic.

Treatments for non-epileptic attack disorder

BACKGROUND

Psychogenic non-epileptic seizures (NES) have the outward appearance of epilepsy in the absence of physiological or electroencephalographic correlates. Non-epileptic seizures can occur in isolation or in combination with epileptic seizures. The development and maintenance of non-epileptic seizures has been well documented and there is a growing literature on the treatment of NES which includes non-psychological (including anti-anxiety and antidepressant pharmacological treatment) and psychological therapies (including cognitive behavioural therapy (CBT), hypnotherapy and paradoxical therapy). Various treatment methodologies have been tried with variable success. The purpose of this Cochrane review was to establish the evidence base for the treatment of NES.

OBJECTIVES

To assess whether treatments for NES result in a reduction in frequency of seizures and/or improvement in quality of life, and whether any treatment is significantly more effective than others.

SEARCH STRATEGY

We searched the Cochrane Epilepsy Group's Specialised Register (September 2005), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2005), MEDLINE (1966 to July 2005), and PsycINFO (1806 to July 2005). No language restrictions were imposed. We checked the reference lists of retrieved studies for additional reports of relevant studies

SELECTION CRITERIA

Randomised or quasi-randomised studies were included that assessed one or more types of psychological or non-psychological interventions for the treatment of NES. Studies of childhood NES were excluded from our review.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed the trials for inclusion and extracted data. Outcomes included reduction in seizure frequency and improvements in quality of life.

MAIN RESULTS

Three small studies met our inclusion criteria and were of poor methodological quality. Two assessed hypnosis and the other paradoxical therapy. There were no detailed reports of improved seizure frequency or quality of life outcomes, and these trials provide no reliable evidence of a beneficial effect of these interventions.

AUTHORS' CONCLUSIONS

In view of the methodological limitations and the small number of studies, we have no reliable evidence to support the use of any treatment including hypnosis or paradoxical injunction therapy in the treatment of NES. Randomised studies of these and other interventions are needed.

Dynamics of carriage of Neisseria meningitidis in a group of military recruits: subtype stability and specificity of the immune response following colonization

Meningococcal carriage and the immune response to colonization were studied in a group of military recruits undergoing basic training. Subtyping by determination of the class 1 protein sequence clearly differentiated between strains and demonstrated the dynamics of carriage and transmission. Expression of class 1 protein by each strain remained stable during prolonged carriage by different subjects. Following colonization, a marked increase in serum bactericidal response occurred, which was specific for the subtype of the acquired strain and was associated with an increase in reactivity by Western blot to the homologous class 1 protein. Subjects colonized by multiple strains showed evidence of a specific immune response to the class 1 protein of each strain acquired. The subtype specificity of the bactericidal response to meningococci and the stability of expression of the class 1 protein have important implications for the design of vaccines for prevention of serogroup B meningococcal disease.

Light-induced spectral changes in fully oxidized cytochrome c oxidase in the presence of oxygen

Illumination of oxidized cytochrome oxidase with low intensity (<2 mW) light below 300 nm in the presence of oxygen causes pH-dependent spectral changes in the Soret and visible regions. The light-induced difference spectra show a peak at 438 nm and a trough at 414 nm in the Soret region and a peak at 606 nm and a shoulder at approximately 577 nm in the visible region. The effect was inhibited by cyanide, suggesting the involvement of cytochrome a3. The pH dependence indicates two titratable groups with pKa values of 6.52 +/- 0.26 and 6.85 +/- 0.15. The spectral changes are analogous to those occurring upon addition of hydrogen peroxide to the fully oxidized enzyme, which results in a mixture of species with absorbance maxima at 607 and 580 nm when referenced against the oxidized enzyme. Catalase addition affected the initial onset of the spectral change and increased the rate at which the reverse reaction occurred upon termination of illumination. The data are consistent with a mechanism involving light-induced autoreduction of the binuclear center and subsequent O2 binding, followed by the release of hydrogen peroxide and the formation of a mixture of the 607 nm and 580 nm forms.

Sequence variation in class 1 outer membrane protein in Neisseria meningitidis isolated from patients with meningococcal infection and close household contacts

The meningococcal porA gene encodes the class 1 outer membrane protein which contains the VR1 and VR2 regions responsible for sero-subtype specificity. However, sequence variations may occur within these regions which are not recognised by the currently available subtype antibodies. Since this "silent" microheterogeneity represents a potential hidden source of information, in the current study we have used porA gene sequence analysis to study strains isolated from cases of meningococcal infection and close household contacts. With each of the three subtypes studied, the index cases could be differentiated from each other by sequence variations within at least one of the VR1, VR2 and SV1 regions. In addition, although isolates from close household contacts showed a high degree of homology significant differences could be detected within some family groups. These data demonstrate that it is possible to use sequence information to differentiate between potential sources of infection which appear identical using conventional serological methods.

Comparison of the class-1 outer membrane protein from B:15:P1.16 Neisseria meningitidis strains isolated from patients previously immunized with a serogroup B outer membrane protein vaccine in Norway

A previous report of a large, double blind, efficacy trial of an experimental Group B meningococcal outer membrane protein vaccine carried out in Norwegian Teenagers, showed a protection rate of 57%. Previous studies had demonstrated the occurrence of mutations in the class-1 outer membrane protein which alter its immunological properties. The occurrence of new mutations might compromise the efficacy of a vaccine and explain the occurrence of any vaccine failures. The porA gene, which encodes expression of the class 1 protein, was sequenced in all isolates from vaccine failures and compared to that of the vaccinating strain H44/76 (B:15:P1.7,16). The porA DNA and deduced amino acid sequences were all identical to that of the vaccinating strain except for that of one isolate which had a sequence identical to strains previously reported in Norway and England with a 'masked P1.7' epitope. The absence of new mutations in the trial was encouraging for the further development of outer membrane protein vaccines.

Experimental enzyme-linked amperometric immunosensors for the detection of salmonellas in foods

Two enzyme-linked amperometric immunosensors specific for salmonellas were developed as rapid methods for quantifying and detecting these organisms in pure cultures and foods. Both used alkaline phosphatase as the enzyme reporter molecule but one system used phenyl phosphate as the substrate followed by the electrochemical detection of phenol at a polarized platinum electrode. The other system incorporated an enzyme amplification step and relied on the electrochemical detection of a reduced mediator, ferrocyanide. Both assays were rapid (4 h) and specific and generated salmonella-dependent signals above 10(4) cfu/ml (phenyl phosphate system) or 10(5) cfu/ml (enzyme amplified system) in pure cultures and samples of several foods, although the results with beef samples showed considerable variation. Both systems were able to detect low (1-5 cfu/g or /ml) numbers of salmonellas in foods after non-selective (18 h) and selective (22 h) enrichment steps but four samples, out of 147, gave false positive results. False positive results were eliminated by reducing the enrichment steps to 6 h and 18 h respectively (90 samples).

Direct application to dairy foods of a Listeria-specific oligonucleotide probe to 16S rRNA

A potentially Listeria-specific 28 base oligonucleotide probe was designed from 16S rRNA sequence data. Using either 32P or non-radioactive (alkaline phosphatase) labels, the probe was shown to be highly specific as it hybridised to RNA extracted from all of the species of Listeria but not to any of the other bacteria tested. Both probe methods were highly sensitive and ca 10(2) cfu/ml Listeria could be detected in pure cultures. A rapid procedure for extracting RNA from milk, Camembert and cottage cheese was developed. This allowed the direct application of the probe to these foods and gave a rapid and specific method of detecting > 10(2) cfu/g or ml Listeria in these foods.

Use of the polymerase chain reaction and oligonucleotide probes for the rapid detection and identification of Carnobacterium species from meat

The polymerase chain reaction (PCR) was used selectively to amplify specific rDNA sequences of Carnobacterium divergens, C. mobile, C. piscicola and C. gallinarum in purified DNA extracts, crude cell lysates and food samples. The PCR products were visualized by agarose gel electrophoresis and identified, at species level, by hybridization reactions with three specific oligonucleotide probes for C. divergens, C. mobile and C. piscicola/C. gallinarum designed from 16S rRNA sequence data. The PCR was sufficiently sensitive to amplify DNA from a single bacterium to detectable levels after 30 cycles of amplification. Both radioactive (32P) and non-radioactive alkaline phosphatase labelled probes was able to detect the PCR products. Detection was highly specific and the probes did not hybridize with DNA samples from any other of the bacterial species tested. These methods enabled the rapid and specific detection and identification of carnobacteria from pure cultures and samples of meat.

The T cell receptor V alpha 11 gene family. Analysis of allelic sequence polymorphism and demonstration of J alpha region-dependent recognition by allele-specific antibodies

Allelic polymorphism in TCR loci may play an important role in shaping the T cell repertoire and in disease susceptibility. We have used a combination of antibody and sequence analysis to investigate polymorphism in the murine V alpha 11 family. Two different antibodies have been analyzed that recognize particular V alpha 11 family members of the V alpha b and V alpha d haplotypes. One antibody shows J alpha dependency, suggesting a conformational element to the epitope. Investigation of the anti-V alpha 11 staining pattern on different mouse strains indicates that there is a marked influence of MHC haplotype on V alpha 11 selection and that V alpha 11 is preferentially expressed on CD4+ cells. Sequence analysis of V alpha 11 genes from the V alpha a, V alpha b, and V alpha d haplotypes shows two potential regions for the haplotype-specific epitopes. The relatedness of the different V alpha 11 family members from different haplotypes suggests that the V alpha 11.1/11.2 gene duplication is relatively recent, but that V alpha 11.3 separated much earlier. Differences between V alpha 11.3 and V alpha 11.1/11.2 are concentrated in the putative complementarity determining regions (CDR), whereas differences between alleles are not clearly clustered. However, the V alpha 11.1a and V alpha 11.1d alleles differ from V alpha 11.1b and V alpha 11.2b in CDR1. A V alpha 11.2-expressing anti-cytochrome c T cell has the same V-J junction as a V alpha 11.1-bearing cell with a similar fine specificity, indicating that V alpha 11.1b and V alpha 11.2b do not contribute different Ag specificities.

The T cell receptor V alpha 11 gene family. Analysis of allelic sequence polymorphism and demonstration of J alpha region-dependent recognition by allele-specific antibodies

Allelic polymorphism in TCR loci may play an important role in shaping the T cell repertoire and in disease susceptibility. We have used a combination of antibody and sequence analysis to investigate polymorphism in the murine V alpha 11 family. Two different antibodies have been analyzed that recognize particular V alpha 11 family members of the V alpha b and V alpha d haplotypes. One antibody shows J alpha dependency, suggesting a conformational element to the epitope. Investigation of the anti-V alpha 11 staining pattern on different mouse strains indicates that there is a marked influence of MHC haplotype on V alpha 11 selection and that V alpha 11 is preferentially expressed on CD4+ cells. Sequence analysis of V alpha 11 genes from the V alpha a, V alpha b, and V alpha d haplotypes shows two potential regions for the haplotype-specific epitopes. The relatedness of the different V alpha 11 family members from different haplotypes suggests that the V alpha 11.1/11.2 gene duplication is relatively recent, but that V alpha 11.3 separated much earlier. Differences between V alpha 11.3 and V alpha 11.1/11.2 are concentrated in the putative complementarity determining regions (CDR), whereas differences between alleles are not clearly clustered. However, the V alpha 11.1a and V alpha 11.1d alleles differ from V alpha 11.1b and V alpha 11.2b in CDR1. A V alpha 11.2-expressing anti-cytochrome c T cell has the same V-J junction as a V alpha 11.1-bearing cell with a similar fine specificity, indicating that V alpha 11.1b and V alpha 11.2b do not contribute different Ag specificities.

Increased sensitivity of an enzyme-amplified colorimetric immunoassay for protein A-bearing Staphylococcus aureus in foods

A modification to the enzyme amplification system described by Self (1984), has been developed in which the addition of semicarbazide hydrochloride increased the sensitivity of detection of protein A-bearing Staphylococcus aureus in foods from 4-6 X 10(3) to 20 colony forming units (c.f.u.) g-1 or ml-1. This may be due to the removal of acetaldehyde produced as a by-product of the amplification cycle thereby permitting further cycling to proceed.

An improved amperometric immunosensor for the detection and enumeration of protein A-bearing Staphylococcus aureus

An amperometric immunosensor specific to the protein A of Staphylococcus aureus, was developed using the direct electrochemical detection of phenol produced by alkaline phosphatase from phenylphosphate. The immunosensor could detect protein A at 0.01 ng/ml and could reliably detect and quantify pure cultures of protein A-bearing Staph. aureus above 10(3) cfu/ml. A similar sensitivity of detection was obtained with samples of beef and milk.

A semi-homogeneous amperometric immunosensor for protein A-bearing Staphylococcus aureus in foods

A semi-homogeneous amperometric immunosensor specific to the protein A of Staphylococcus aureus was developed using direct electrochemical detection of phenol produced by alkaline phosphatase from phenyl phosphate. The immunosensor could reliably detect strains of protein A-bearing S. aureus in pure cultures at ca. 10(4) cfu/ml, and at ca. 10(5) cfu/g or ml in various food samples. Due to its semi-homogeneous nature, the system was very simple, easy to operate, and labour-saving. The good correlation between the amperometric current generated by the immunosensor and plate counts illustrated the potential usefulness of this simple system. It proved to be a reliable 24-h detection method for food samples containing very low numbers of protein A-bearing S. aureus after pre-enrichment, as it was able to detect cells that could not directly be enumerated by plate counts.

Sensitive enzyme-amplified electrical immunoassay for protein A-bearing Staphylococcus aureus in foods

An amperometric electrochemical immunoassay specific for protein A-bearing Staphylococcus aureus was developed. The method was based on a sandwich immunosorbent assay and incorporated an enzyme amplification step, using a NAD-specific redox cycle generating NADH (C. H. Stanley, A. Johannsson, and C. H. Self, J. Immunol. Methods 83:89-95, 1985). Reduction of the mediator, ferricyanide, was dependent on the initial concentration of antigen. The final potential was measured by using a Pt disk electrode polarized at +0.8 V to the Ag/AgCl reference electrode. The assay was rapid (4 h) and generated protein A- and cell (S. aureus)-dependent signals. The system was highly sensitive and could detect 10 pg of protein A ml-1 and less than 100 CFU of S. aureus ml-1. Similar sensitivities were observed with S. aureus cultures inoculated into beef and milk, but the sensitivity was reduced slightly (ca. 10(3) g-1) with samples of Cheddar cheese.

Development and performance of an enzyme-linked amperometric immunosensor for the detection of Staphylococcus aureus in foods

An amperometric enzyme-linked immunosensor was developed to detect and quantify levels of Staphylococcus aureus electrically in pure cultures and in foods. The assay was a modification of a 'sandwich' ELISA for the protein A of Staph. aureus, employing catalase-labelled anti-protein A antibody. On addition of hydrogen peroxide to the assay system the catalase released O2 which was monitored using an amperometric oxygen electrode. The rate of current increase was proportional to the antigen concentration (protein A or Staph. aureus). Protein A was detected reliably at 0.1 ng/ml representing a 20-fold increase in sensitivity over the conventional ELISA that used horseradish peroxidase. Pure cultures of Staph. aureus were detected at 10(-3)-10(-4) cfu/ml with the amperometric electrode (cf greater than 10(5)/ml for conventional ELISA). The same level of sensitivity was achieved for inoculated food samples. Low levels of contamination (1 cfu/g) of Staph. aureus were detected after incubation at 37 degrees C for 18 h, and the immunosensor could from the basis of a test for screening and identification of protein A-bearing Staph. aureus in 24 h, although natural variations in protein A content between different strains could make the system unreliable in accurate quantification of cell numbers.

Transluminal angioplasty versus surgical repair for stenosis of hemodialysis grafts. A randomized study

A randomized study of transluminal angioplasty versus surgical revision for stenosis at the venous end of hemodialysis grafts was carried out. Median patency for the surgical group was 12 months versus only 4 months for the transluminal angioplasty group. This difference was statistically significant (p less than 0.01). In addition, the average cost for surgical revision was slightly less than that for transluminal angioplasty. Therefore, for long-term patency, surgical treatment is the method of choice, although under special circumstances there may still be a role for transluminal angioplasty.

Fiber-optic interferometric sensor arrays with freedom from source phase-induced noise

We propose arrays of all-passive remote sensors with freedom from both source phase-induced intensity noise and cross talk between sensors. These arrays employ high-duty-cycle time-domain addressing, utilize laser diodes, and have downlead insensitivity. A synthetic heterodyne demodulation technique is used to prevent environmentally induced signal fading. An experimental all-fiber implementation of a single remote sensor yielded a measured sensitivity of below 40 microrad/ radicalHz at signal frequencies above 600 Hz.

Oxidase reactions of tomato anionic peroxidase

Tomato (Lycopersicon esculentum Mill) anionic peroxidase was found to catalyze oxidase reactions with NADH, glutathione, dithiothreitol, oxaloacetate, and hydroquinone as substrates with a mean activity 30% that of horseradish peroxidase; this is in contrast to the negligible activity of the tomato enzyme as compared to the horseradish enzyme in catalyzing an indoleacetic acid-oxidase reaction with only Mn(2+) and a phenol as cofactors. Substitution of Ce(3+) for Mn(2+) produced an 18-fold larger response with the tomato enzyme than with the horseradish enzyme, suggesting a significant difference in the autocatalytic indoleacetic acid-oxidase reactions with these two enzymes. In attempting to compare enzyme activities with 2,4-dichlorophenol as a cofactor, it was found that reaction rates increased exponentially with both increasing cofactor concentration and increasing enzyme concentration. While the former response may be analogous to allosteric control of enzyme activity, the latter response is contrary to the principle that reaction rate is proportional to enzyme concentration, and additionally makes any comparison of enzyme activity difficult.

Amebic colitis. Preventing morbidity and mortality from fulminant disease

Uncomplicated amebic colitis is readily treated and has a mortality rate of less than 0.5%. Complications necessitating surgical intervention develop in only 6% to 11% of patients with symptomatic disease. However, the mortality rate in these patients ranges from 40% to 100% and stems in part from delays in diagnosis and treatment. Patients with known amebic colitis who show signs of systemic toxicity or of localized or generalized peritonitis are at high risk for complications; surgical consultation should be obtained. Patients who are thought to have acute appendicitis, diverticulitis, or obstructive or perforative carcinoma but have a history of dysentery atypical of that in these conditions should also be evaluated for amebiasis. Such patients should be treated presumptively until the diagnosis of amebic colitis can be excluded.

Active polarization coupler for birefringent fiber

Static coupling between polarization modes achieved by periodically stressing birefringent fiber once per beat length was recently reported. The same scheme is now used to obtain coupling modulation at kilohertz-to-megahertz frequencies by applying pressure to the fiber with an oscillating piezoelectric ceramic. An amplitude of 30-50 V (peak to peak) was found to be necessary to modulate the polarization coupling from a minimum to a maximum. Polarization modulation is also achieved by applying stress along one fiber polarization axis between the two static couplers of a Mach-Zehnder interferometer.

Two-mode fiber modal coupler

When a single-mode fiber is used at a wavelength below the cutoff wavelength, the fiber guides second-order modes, which travel at different phase velocities from the fundamental mode. Periodically stressing this two-mode fiber once per beat length can cause coherent coupling between the modes. Such a modal coupler has been developed and is described here. Coupling to one of the second-order modes has been achieved, leaving less than -40-dB residual power in the fundamental mode. Two couplers have been mounted on a single strand of fiber to construct a Mach-Zehnder interferometer with better than a 30-dB on/off ratio. The coupler is polarization sensitive and can be used as an in-line polarizer. A 36-dB extinction ratio between polarizations has been observed.

Birefringent-fiber polarization coupler

Periodically stressing a birefringent fiber once per beat length can cause coherent coupling to occur between polarization modes. Such a birefringent-fiber polarization coupler is described here. More than 30 dB of power transfer between polarizations has been achieved. The device has been used as the output coupler of an in-line Mach-Zehnder interferometer, and better than 25-dB on/off extinction has been measured. The device is wavelength selective and can be used as a multiplexer or as a notch filter. A notch of 9-nm full width at half-maximum has been achieved with a 60-period comb structure.

Stimulation of peroxidase reactions by hydroxamates

Salicylhydroxamic acid, benzohydroxamic acid, and phenylacetohydroxamic acid were found to stimulate the oxidation of NADH, dithiothreitol, and ferrocyanide by horseradish peroxidase. The hydroxamates themselves served as substrates in peroxidase reactions, and the observed stimulations may involve hydroxamate free-radical formation.

Prognostic significance of hormone receptors in early recurrence of breast cancer

A retrospective analysis of 155 patients with primary infiltrating breast cancer was carried out to determine the prognostic significance of hormone receptor values and analyze the effect of adjuvant chemotherapy. Estrogen receptor-negative patients were found to have a significantly higher recurrence rate than estrogen receptor-positive patients (p less than 0.005). No difference was found based on the progesterone receptor value. The data strongly suggest a favorable response to adjuvant chemotherapy administered on the basis of the estrogen receptor value alone.