Understanding Accelerated Summer Body Mass Index Gain by Tracking Changes in Children's Height, Weight, and Body Mass Index Throughout the Year

Background: Drivers of summer body mass index (BMI) gain in children remain unclear. The Circadian and Circannual Rhythm Model (CCRM) posits summer BMI gain is biologically driven, while the Structured Days Hypothesis (SDH) proposes it is driven by reduced structure. Objectives: Identify the mechanisms driving children's seasonal BMI gain through the CCRM and SDH. Methods: Children's (N = 147, mean age = 8.2 years) height and weight were measured monthly during the school year, and once in summer (July-August). BMI z-score (zBMI) was calculated using CDC growth charts. Behaviors were measured once per season. Mixed methods regression estimated monthly percent change in children's height (%HΔ), weight (%WΔ), and monthly zBMI for school year vs. summer vacation, seasonally, and during school months with no breaks vs. school months with a break ≥1 week. Results: School year vs. summer vacation analyses showed accelerations in children's %WΔ (Δ = 0.9, Standard Error (SE) = 0.1 vs. Δ = 1.4, SE = 0.1) and zBMI (Δ = -0.01, SE = 0.01 vs. Δ = 0.04, SE = 0.3) during summer vacation, but %HΔ remained relatively constant during summer vacation compared with school (Δ = 0.3, SE = 0.0 vs. Δ = 0.4, SE = 0.1). Seasonal analyses showed summer had the greatest %WΔ (Δ = 1.8, SE = 0.4) and zBMI change (Δ = 0.05, SE = 0.03) while %HΔ was relatively constant across seasons. Compared with school months without a break, months with a break showed higher %WΔ (Δ = 0.7, SE = 0.1 vs. Δ = 1.6, SE = 0.2) and zBMI change (Δ = -0.03, SE = 0.01 vs. Δ = 0.04, SE = 0.01), but %HΔ was constant (Δ = 0.4, SE = 0.0 vs. Δ = 0.3, SE = 0.1). Fluctuations in sleep timing and screen time may explain these changes. Conclusions: Evidence for both the CCRM and SDH was identified but the SDH may more fully explain BMI gain. Interventions targeting consistent sleep and reduced screen time during breaks from school may be warranted no matter the season.

Comparison of raw accelerometry data from ActiGraph, Apple Watch, Garmin, and Fitbit using a mechanical shaker table

The purpose of this study was to evaluate the reliability and validity of the raw accelerometry output from research-grade and consumer wearable devices compared to accelerations produced by a mechanical shaker table. Raw accelerometry data from a total of 40 devices (i.e., n = 10 ActiGraph wGT3X-BT, n = 10 Apple Watch Series 7, n = 10 Garmin Vivoactive 4S, and n = 10 Fitbit Sense) were compared to reference accelerations produced by an orbital shaker table at speeds ranging from 0.6 Hz (4.4 milligravity-mg) to 3.2 Hz (124.7mg). Two-way random effects absolute intraclass correlation coefficients (ICC) tested inter-device reliability. Pearson product moment, Lin's concordance correlation coefficient (CCC), absolute error, mean bias, and equivalence testing were calculated to assess the validity between the raw estimates from the devices and the reference metric. Estimates from Apple, ActiGraph, Garmin, and Fitbit were reliable, with ICCs = 0.99, 0.97, 0.88, and 0.88, respectively. Estimates from ActiGraph, Apple, and Fitbit devices exhibited excellent concordance with the reference CCCs = 0.88, 0.83, and 0.85, respectively, while estimates from Garmin exhibited moderate concordance CCC = 0.59 based on the mean aggregation method. ActiGraph, Apple, and Fitbit produced similar absolute errors = 16.9mg, 21.6mg, and 22.0mg, respectively, while Garmin produced higher absolute error = 32.5mg compared to the reference. ActiGraph produced the lowest mean bias 0.0mg (95%CI = -40.0, 41.0). Equivalence testing revealed raw accelerometry data from all devices were not statistically significantly within the equivalence bounds of the shaker speed. Findings from this study provide evidence that raw accelerometry data from Apple, Garmin, and Fitbit devices can be used to reliably estimate movement; however, no estimates were statistically significantly equivalent to the reference. Future studies could explore device-agnostic and harmonization methods for estimating physical activity using the raw accelerometry signals from the consumer wearables studied herein.

The utility of behavioral biometrics in user authentication and demographic characteristic detection: a scoping review

BACKGROUND

Objective measures of screen time are necessary to better understand the complex relationship between screen time and health outcomes. However, current objective measures of screen time (e.g., passive sensing applications) are limited in identifying the user of the mobile device, a critical limitation in children's screen time research where devices are often shared across a family. Behavioral biometrics, a technology that uses embedded sensors on modern mobile devices to continuously authenticate users, could be used to address this limitation.

OBJECTIVE

The purpose of this scoping review was to summarize the current state of behavioral biometric authentication and synthesize these findings within the scope of applying behavioral biometric technology to screen time measurement.

METHODS

We systematically searched five databases (Web of Science Core Collection, Inspec in Engineering Village, Applied Science & Technology Source, IEEE Xplore, PubMed), with the last search in September of 2022. Eligible studies were on the authentication of the user or the detection of demographic characteristics (age, gender) using built-in sensors on mobile devices (e.g., smartphone, tablet). Studies were required to use the following methods for authentication: motion behavior, touch, keystroke dynamics, and/or behavior profiling. We extracted study characteristics (sample size, age, gender), data collection methods, data stream, model evaluation metrics, and performance of models, and additionally performed a study quality assessment. Summary characteristics were tabulated and compiled in Excel. We synthesized the extracted information using a narrative approach.

RESULTS

Of the 14,179 articles screened, 122 were included in this scoping review. Of the 122 included studies, the most highly used biometric methods were touch gestures (n = 76) and movement (n = 63), with 30 studies using keystroke dynamics and 6 studies using behavior profiling. Of the studies that reported age (47), most were performed exclusively in adult populations (n = 34). The overall study quality was low, with an average score of 5.5/14.

CONCLUSION

The field of behavioral biometrics is limited by the low overall quality of studies. Behavioral biometric technology has the potential to be used in a public health context to address the limitations of current measures of screen time; however, more rigorous research must be performed in child populations first.

SYSTEMATIC REVIEW REGISTRATION

The protocol has been pre-registered in the Open Science Framework database ( https://doi.org/10.17605/OSF.IO/92YCT ).

Estimating Physical Activity and Sleep using the Combination of Movement and Heart Rate: A Systematic Review and Meta-Analysis

The purpose of this meta-analysis was to quantify the difference in physical activity and sleep estimates assessed via 1) movement, 2) heart rate (HR), or 3) the combination of movement and HR (MOVE+HR) compared to criterion indicators of the outcomes. Searches in four electronic databases were executed September 21-24 of 2021. Weighted mean was calculated from standardized group-level estimates of mean percent error (MPE) and mean absolute percent error (MAPE) of the proxy signal compared to the criterion measurement method for physical activity, HR, or sleep. Standardized mean difference (SMD) effect sizes between the proxy and criterion estimates were calculated for each study across all outcomes, and meta-regression analyses were conducted. Two-One-Sided-Tests method were conducted to metaanalytically evaluate the equivalence of the proxy and criterion. Thirty-nine studies (physical activity k = 29 and sleep k = 10) were identified for data extraction. Sample size weighted means for MPE were -38.0%, 7.8%, -1.4%, and -0.6% for physical activity movement only, HR only, MOVE+HR, and sleep MOVE+HR, respectively. Sample size weighted means for MAPE were 41.4%, 32.6%, 13.3%, and 10.8% for physical activity movement only, HR only, MOVE+HR, and sleep MOVE+HR, respectively. Few estimates were statistically equivalent at a SMD of 0.8. Estimates of physical activity from MOVE+HR were not statistically significantly different from estimates based on movement or HR only. For sleep, included studies based their estimates solely on the combination of MOVE+HR, so it was impossible to determine if the combination produced significantly different estimates than either method alone.

Preconception exposures and adverse pregnancy, birth and postpartum outcomes: Umbrella review of systematic reviews

BACKGROUND

Preconception exposures have been associated with adverse pregnancy, birth and postpartum outcomes. However, the reports, statements and guidelines of national and international health organisations vary in what they recommend individuals should monitor, avoid, reduce or practise in the preconception period.

OBJECTIVES

To synthesise and evaluate the evidence across systematic reviews for associations between exposures before conception and adverse pregnancy, birth and postpartum outcomes.

DATA SOURCES

MEDLINE, Embase, Epistemonikos (to May 2020) and reference lists of included reviews, without language or date restrictions.

STUDY SELECTION, DATA EXTRACTION AND SYNTHESIS

Systematic literature reviews of observational and/or interventional studies reporting associations between preconception exposures in women and/or men of reproductive age and pregnancy, birth or postpartum health outcomes were included. The methodological quality of reviews and the certainty of the evidence underlying each exposure-outcome association were assessed using AMSTAR 2 and the GRADE approach.

RESULTS

We identified 53 eligible reviews reporting 205 unique exposure-outcome associations. Methodological quality was generally low with only two reviews rated as 'high' quality and two as 'moderate'. We found high-certainty, randomised trial evidence that maternal folate supplementation reduces the risk of neural tube defects and anomaly-related terminations. Moderate-certainty, observational evidence was found that maternal physical activity is associated with reduced risk of pre-eclampsia and gestational diabetes, and that paternal age of ≥40 years and maternal body mass index (BMI) and interpregnancy weight gain are associated with increased risk of various adverse pregnancy and birth outcomes. Low- and very low-certainty evidence was found for other associations.

CONCLUSIONS

Clinicians and policymakers can be confident that maternal folate supplementation should be encouraged during the preconception period. There is moderate certainty in the evidence base that maternal physical activity, BMI and interpregnancy weight gain and advanced paternal age are important preconception considerations. High-quality research is required to better understand other exposure-outcome associations.

Abnormal left-sided blood volume, wall shear stress & energy loss in patients with repaired Tetralogy of Fallot identified by 4D flow MRI

Introduction

Tetralogy of Fallot (TOF) occurs in 4 of every 10,000 live births and is the most common form of cyanotic congenital heart disease. Patients with repaired TOF (rTOF) require long-term and frequent monitoring for many complications that may arise. The hemodynamic alterations that contribute to the quality of life and outcomes for these patients are understudied and poorly understood.

Purpose

The objective of this study was to use 4D Flow MRI to assess flow hemodynamics in patients with rTOF to better identify and predict altered hemodynamic patterns to assist with future interventions. We hypothesized, patients with rTOF will have abnormal left-sided flow hemodynamics compared to healthy controls resulting in poorer hemodynamic patterns even after post-repair.

Methods

A total of 20 rToF patients (age = 34.5±11.2, female = 5) and 20 healthy controls (age = 37.0±12.1, female = 6) were enrolled in this study and underwent standard cardiac MRI followed by 4D Flow MRI acquisition. Figure 1 demonstrates the workflow of the analysis that was performed using cvi42 v5.11 (Circle Cardiovascular Imaging Inc., Calgary, Canada). The Aorta and LV were segmented, flow visualization and quantitative flow analysis were performed by placing analysis planes perpendicular to the flow of interest as shown in Figure 1. Total volume (TV), Wall Shear Stress Axial (WSSax), circumferential (WSScirc) and energy loss (EL) were calculated. Statistics were analyzed using IBM SPSS Statistics, version 27. An independent-samples t-test was used to compare parameters and identify significant differences between controls and patients. A P-value <0.05 was considered significant.

Results

In comparison to controls, TV of the STJ (66.89±17.33 vs. 82.28±18.77, p=0.011), Aao (56.05±10.71 vs. 73.04±19.66, p=0.002), and 1st Aortic Arch (AAr) (56.88±12.97 vs. 69.52±18.65, p=0.017) were lower in rTOF patients. In addition, patients with rTOF had higher average WSSax in the LVOT (0.13±0.05 vs. 0.10±0.03, p=0.049), STJ (0.10±0.02 vs. 0.07±0.02, p=0.001), and Aao (0.10±0.03 vs. 0.08±0.02, p<0.000) compared to controls. Moreover, average WSScirc in the LVOT (0.07±0.02 vs. 0.05±0.01, p=0.010), STJ (0.07±0.02 vs. 0.05±0.01, p=0.006), Aao (0.07±0.02 vs. 0.05±0.01, p=0.004), and 1st AAr (0.06±0.02 vs. 0.05±0.01, p=0.017) were higher in patients compared to controls. Lastly, EL in the Aao was lower in patients compared to controls (1.87±0.83 vs. 2.47±1.03, p=0.049). Significant results are demonstrated in Table 1, red illustrating lower values in patients compared to controls and green illustrating higher values.

Conclusion

This study unveiled abnormal left-sided blood flow in rToF patients with reduced TV and increased WSSax, average WSScirc and EL. These new hemodynamic insights obtained from 4D flow MRI may help to inform future individualized decision-making for patients with rTOF.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): University of Calgary

Homelessness in early adulthood and biomedical risk factors by middle-age: the 1970 British Cohort Study

Background

Homelessness has been linked to premature mortality but the relationship with biomedical risk factors is uncertain.

Methods

We analysed data from 8581 participants in the 1970 British Birth Cohort Study. Homelessness and type of experience were self-reported at 30 years of age. Nine biomarkers outcomes were collected at 46 years of age: body mass index (BMI), blood pressure, total and high-density cholesterol, triglycerides, glycated haemoglobin, C-reactive protein (CRP), insulin-like growth factor 1 and we computed the 10-year risk for coronary heart disease.

Results

By 30 years of age, 5.8% of participants had been homeless with sofa surfing the most common experience (4.3%). Homelessness was associated with socioeconomic disadvantage, mental health problems and substance use in early adulthood, but these differences were not expressed in biomarkers. After accounting for early adulthood characteristics, residing in a bed and breakfast was associated with a higher BMI (0.59, 95% CI 0.13 to 1.05) and CRP (0.16, 95% CI 0.04 to 0.29), squatting with a lower BMI (−1.69, 95% CI –3.08 to −0.21) and rough sleeping with a higher 10-year risk of coronary heart disease (0.03, 95% CI 0.01 to 0.05).

Conclusions

Exposure to homelessness in early adulthood was essentially unrelated to biomarkers in middle age. Inconsistent links were found for specific types of experience.

Influence of protogynous sex change on recovery of fish populations within marine protected areas

Marine protected areas (MPAs) are increasingly implemented as a conservation tool worldwide. In many cases, they are managed adaptively: the abundance of target species is monitored, and observations are compared to some model-based expectation for the trajectory of population recovery to ensure that the MPA is achieving its goals. Most previous analyses of the transient (short-term) response of populations to the cessation of fishing inside MPAs have dealt only with gonochore (fixed-sex) species. However, many important fishery species are protogynous hermaphrodites (female-to-male sex-changing). Because size-selective harvest will predominantly target males in these species, harvesting not only reduces abundance but also skews the sex ratio toward females. Thus the response to MPA implementation will involve changes in both survival and sex ratio, and ultimately reproductive output. We used an age-structured model of a generic sex-changing fish population to compare transient population dynamics after MPA implementation to those of an otherwise similar gonochore population and examine how different features of sex-changing life history affect those dynamics. We examined both demographically open (most larval recruitment comes from outside the MPA) and demographically closed (most larval recruitment is locally produced) dynamics. Under both scenarios, population recovery of protogynous species takes longer when fishing was more intense pre-MPA (as in gonochores), but also depends heavily on the mating function, the degree to which the sex ratio affects reproduction. If few males are needed and reproduction is not affected by a highly female-biased sex ratio, then population recovery is much faster; if males are a limiting resource, then increases in abundance after MPA implementation are much slower than for gonochores. Unfortunately, the mating function is largely unknown for fishes. In general, we expect that most protogynous species with haremic mating systems will be in the first category (few males needed), though there is at least one example of a fish species (though not a sex-changing species) for which males are limiting. Thus a better understanding of the importance of male fish to population dynamics is needed for the adaptive management of MPAs.

Introducing the GRACEnet/REAP Data Contribution, Discovery, and Retrieval System

Difficulties in accessing high-quality data on trace gas fluxes and performance of bioenergy/bioproduct feedstocks limit the ability of researchers and others to address environmental impacts of agriculture and the potential to produce feedstocks. To address those needs, the GRACEnet (Greenhouse gas Reduction through Agricultural Carbon Enhancement network) and REAP (Renewable Energy Assessment Project) research programs were initiated by the USDA Agricultural Research Service (ARS). A major product of these programs is the creation of a database with greenhouse gas fluxes, soil carbon stocks, biomass yield, nutrient, and energy characteristics, and input data for modeling cropped and grazed systems. The data include site descriptors (e.g., weather, soil class, spatial attributes), experimental design (e.g., factors manipulated, measurements performed, plot layouts), management information (e.g., planting and harvesting schedules, fertilizer types and amounts, biomass harvested, grazing intensity), and measurements (e.g., soil C and N stocks, plant biomass amount and chemical composition). To promote standardization of data and ensure that experiments were fully described, sampling protocols and a spreadsheet-based data-entry template were developed. Data were first uploaded to a temporary database for checking and then were uploaded to the central database. A Web-accessible application allows for registered users to query and download data including measurement protocols. Separate portals have been provided for each project (GRACEnet and REAP) at nrrc.ars.usda.gov/slgracenet/#/Home and nrrc.ars.usda.gov/slreap/#/Home. The database architecture and data entry template have proven flexible and robust for describing a wide range of field experiments and thus appear suitable for other natural resource research projects.

Management of severe Dupuytren's contracture of the proximal interphalangeal joint with use of a central slip facilitation device

Thirty-eight fingers in 27 patients with Dupuytren's contracture of the proximal interphalangeal joint (PIPJ) in excess of 70° were treated using a staged technique. The first stage involved applying a mini external fixator across the PIPJ for continuous extension over 6 weeks with intensive hand therapy to maintain mobility of the joint and help correct the deformity. Twice weekly during hand therapy sessions the tension of the elastic band across the mini ex-fix was increased, allowing that full active flexion of the PIPJ against the elastic band could still be achieved. The second stage, 4 weeks after the external fixator was applied, involved an open palm technique of fasciectomy for the contracted cords restricting metacarpophalangeal joint movement and dermofasciectomy with full-thickness skin grafting over the proximal phalanx for bands restricting PIPJ movement. The external fixator was used to maintain active extension force until the graft healed. It was generally removed in the outpatient clinic under ring block 2 weeks after the second stage procedure. The patients were followed for a mean of 20.6 (6-48) months. The mean preoperative PIPJ deformity improved from 75° to 37° postoperatively. Overall, 69% of results were rated as good to excellent. Only one patient reported any on-going functional problems. There were eight cases of pin site infections and one case each of loose pins, osteoarthritics at the PIPJ, reflex sympathetic dystrophy, and disease recurrence needing PIPJ fusion. We conclude that our simple staged procedure is a valid alternative in the management of severe Dupuytren's PIPJ contracture.

Intelligence quotient in childhood and the risk of illegal drug use in middle-age: the 1958 National Child Development Survey

PURPOSE

High childhood IQ test scores have been associated with increased alcohol dependency and use in adult life, but the relationship between childhood IQ and illegal drug use in later life is unclear.

METHODS

Participants were 6713 members of the 1958 National Child Development Survey whose IQ was assessed at 11 years and had their lifetime illegal drug use measured at 42 years of age.

RESULTS

In analyses adjusted for a range of covariates, a 1 SD (15-point) increase in IQ scores was associated with an increased risk of illegal drug use in women: ever using cannabis (odds ratio [OR], 1.30; 95% confidence interval [95% CI], 1.16-1.45), cocaine (OR, 1.66; 95% CI, 1.21-2.27), amphetamines (OR, 1.50; 95% CI, 1.22-1.83), amyl nitrate (OR, 1.79; 95% CI, 1.30-2.46) and "magic mushrooms" (OR, 1.52; 95% CI, 1.18-1.98). Associations were of lower magnitude in men.

CONCLUSIONS

In this cohort, high childhood IQ was related to illegal drug use in adulthood.

Pile mixing increases greenhouse gas emissions during composting of dairy manure

The effect of pile mixing on greenhouse gas (GHG) emissions during dairy manure composting was determined using large flux chambers designed to completely cover replicate pilot-scale compost piles. GHG emissions from compost piles that were mixed four times during the 80 day trial were approximately 20% higher than emissions from unmixed (static) piles. For both treatments, carbon dioxide (CO(2)), methane (CH(4)), and nitrous oxide (N(2)O) accounted for 75-80%, 18-21%, and 2-4% of GHG emissions, respectively. Seventy percent of CO(2) emissions and 95% of CH(4) emissions from all piles occurred within first 23 days. By contrast, 80-95% of N(2)O emissions occurred after this period. Mixed and static piles released 2 and 1.6 kg GHG (CO(2)-Eq.) for each kg of degraded volatile solids (VS), respectively. Our results suggest that to minimize GHG emissions, farmers should store manure in undisturbed piles or delay the first mixing of compost piles for approximately 4 weeks.

Resistance of β-casein at the air-water interface to enzymatic cleavage

X-ray reflectivity from an air-buffer interfacial β-casein monomolecular film placed on a solution of chymosin (renin) showed unexpectedly slow proteolytic cleavage. To understand this, the separate structures of β-casein and chymosin, the presentation of each molecule to the other at the air/liquid interface, and that of their mixtures is reported. At the air/solution interface, the hydrophobicity of the protein molecules causes orientation and some deformation of the conformation. When β-casein was presented to a chymosin monomolecular interfacial film, the chymosin was largely displaced from the surface, which was accounted for by the different surfactancy of the two molecules at 25 °C. There was no observable proteolysis. In the reverse experiment, a significant enzymatic degradation and the signature of hydrophobic fragments was observed but only at and above an enzyme concentration of 0.015 mg/mL in the substrate. For comparison, the air/solution interface of premixed β-casein with chymosin in phosphate buffer showed that the film was composed of β-casein proteolytic fragments and chymosin.

A Large Northern Hemisphere Terrestrial CO2 Sink Indicated by the 13C/12C Ratio of Atmospheric CO2

Measurements of the concentrations and carbon-13/carbon-12 isotope ratios of atmospheric carbon dioxide can be used to quantify the net removal of carbon dioxide from the atmosphere by the oceans and terrestrial plants. A study of weekly samples from a global network of 43 sites defined the latitudinal and temporal patterns of the two carbon sinks. A strong terrestrial biospheric sink was found in the temperate latitudes of the Northern Hemisphere in 1992 and 1993, the magnitude of which is roughly half that of the global fossil fuel burning emissions for those years. The challenge now is to identify those processes that would cause the terrestrial biosphere to absorb carbon dioxide in such large quantities.

Once daily dosing of aminoglycosides in pediatric cystic fibrosis patients: a review of the literature

Patients with cystic fibrosis receive many courses of antibiotic therapy throughout their lifetime. Dosing aminoglycosides once daily has become common practice in many of these individuals. Due to ease of home administration, decreased nursing time, and improved quality of life, this regimen is being increasingly explored in the cystic fibrosis population. Because patients with cystic fibrosis have increased aminoglycoside clearance, once daily dosing may result in a prolonged time during the dosing interval when concentrations of the drug may be undetectable. This makes the use of once daily dosing of these antibiotics in patients with cystic fibrosis controversial. Although aminoglycosides exhibit a post antibiotic effect, the duration of this effect is unknown in humans; therefore, the development of resistance to the aminoglycoside is a concern. This manuscript will review the organisms most commonly associated with a pulmonary exacerbation of cystic fibrosis, the properties of the aminoglycoside that make once daily dosing feasible, the concept of once daily dosing in those with cystic fibrosis and the current literature regarding efficacy, monitoring, toxicity and concerns of resistance with once daily dosing in this population.

Septic arthritis due to Aeromonas hydrophila: case report and review of the literature

Aeromonas hydrophila is a rare human pathogen, and worldwide, soft tissue infections following water-related injuries are the most common. However, septic arthritis due to A. hydrophila remains uncommon with only seven cases previously reported in the English literature. In this report, we describe the important clinical features, microbiological findings and management of severe septic arthritis of the knee due to A. hydrophila in a healthy 13-year-old girl following an injury sustained in a private fresh water lake. A review of seven previously reported cases of septic arthritis due to A. hydrophila and the present case suggests that the infection commonly affected the knee and the meta-/intercarpal-phalangeal joint and was frequently rapidly progressive following trauma in fresh water and or associated with leukaemia. Second and third generation cephalosporins, gentamicin, trimethoprim, ciprofloxacin and appropriate orthopaedic management should be promptly instituted. After chemical treatment and chlorination, fresh water becomes free of coliforms, but A. hydrophila persists more compared with the other strains of aeromonas, namely A. sobria and A. caviae. Seawater injuries, unlike freshwater injuries, are not usually associated with aeromonas infections. Further workup on the mechanisms of A. hydrophila resistance to chlorination could probably yield useful information in achieving new procedures of preventing and controlling such infections in public and private fresh water recreational facilities.

Time-dependent changes in the formation of titania-based films at the air-water interface

The growth of surfactant-assisted titanium dioxide-based films at the air-water interface previously reported (Henderson et al. Aust. J. Chem. 2003, 56, 933) has been monitored with a time resolution of minutes over the whole growth period by X-ray energy-dispersive reflectometry. Two new phenomena are described: (a) short-term shifts in the Bragg spacing of the layer structure and (b) the periodic disappearance of the diffraction from the film. We associate these with changes in the chemistry of the reacting mixture, with changes in the packing of the templated titanium species, and with macroscopic and (possibly) microscopic rippling of the solid film during growth.

Scaled structures in late stages of microphase separation of binary paraffin mixtures

Since the dynamic properties in paraffin mixtures are different from those in alloys and polymer blends, paraffin mixtures are believed to be another class of substances establishing the "universality" of the dynamical scaling behavior of phase separation. In this paper, the scaled structures of microphase separation in paraffin mixtures are described using a scaling function based on a two-phase model with kinetics based on the Cahn-Hilliard equation. It has been demonstrated that at the late stages of the microphase separation the scaling behavior in the paraffin mixtures agrees well with the universal features predicted by the scaling function. The scaled structures of microphase separation in paraffin mixtures can be directly calculated from the volume fraction of the minority phase without any adjustable parameter.

Women's vulnerability to sexual assault from adolescence to young adulthood

PURPOSE

To study the vulnerability to sexual assault among undergraduate women.

METHODS

The respondents were demographically representative of undergraduate women in state-supported universities in the United States. Participants (N = 1569) were surveyed using the Sexual Experiences Survey at the beginning and end of their 1st year and at the end of each of the next 3 years of their undergraduate career. Survival analysis was used to determine the risk of initial victimization during specific time intervals from the age of 14 years through the collegiate years as a function of prior victimization. Odds analyses were used to analyze the main and interactive effects of victimization at prior time periods on the probability of victimization at subsequent time periods.

RESULTS

Victimization before the age of 14 years almost doubled the risk of later adolescent victimization (1.8). Furthermore, for those with and without childhood victimization, the risk of an initial sexual assault after the age of 14 years occurred most often in late adolescence, and declined each year thereafter (aged 18-22 years). Sexual victimization among university women was highest for those who had been first assaulted in early adolescence (4.6 times nonvictims). Detailed analyses revealed that the more severe the adolescent experience the greater the risk of collegiate revictimization. Adolescent victims of rape or attempted rape, in particular, were 4.4 times more likely to be as seriously assaulted during their 1st year of college.

CONCLUSION

A linear path model is suggested. Childhood victimization increased the risk of adolescent victimization, which in turn significantly affected the likelihood of revictimization among college women.

Global carbon sinks and their variability inferred from atmospheric O2 and delta13C

Recent time-series measurements of atmospheric O2 show that the land biosphere and world oceans annually sequestered 1.4 +/- 0.8 and 2.0 +/- 0.6 gigatons of carbon, respectively, between mid-1991 and mid-1997. The rapid storage of carbon by the land biosphere from 1991 to 1997 contrasts with the 1980s, when the land biosphere was approximately neutral. Comparison with measurements of delta13CO2 implies an isotopic flux of 89 +/- 21 gigatons of carbon per mil per year, in agreement with model- and inventory-based estimates of this flux. Both the delta13C and the O2 data show significant interannual variability in carbon storage over the period of record. The general agreement of the independent estimates from O2 and delta13C is a robust signal of variable carbon uptake by both the land biosphere and the oceans.

Apoptosis with positive direct immunofluorescence findings in a patient with necrolytic migratory erythema

A 45-year-old man with a glucagonoma and necrolytic migratory erythema is described. Clinical, radiographic, and histologic features were typical for this syndrome. However, a skin biopsy specimen for direct immunofluorescence examination revealed apoptotic keratinocytes that stained positive with immunoglobulins, fibrinogen, and C3. These immunofluorescence findings were initially interpreted erroneously as showing erythema multiforme or a related disorder. We present a unique case of necrolytic migratory erythema with positive direct immunofluorescence findings reflecting immunoglobulin and complement deposition within dyskeratotic epithelial cells.

Weber-Christian panniculitis: a review of 30 cases with this diagnosis

BACKGROUND

More than 60 years ago, Christian described a panniculitis that was later termed Weber-Christian disease.

OBJECTIVE

The purpose of this study was to investigate whether this is a specific disease or a nonspecific disease that embraces several specific conditions.

METHODS

We studied 30 cases diagnosed as Weber-Christian panniculitis and found it possible to make a more specific diagnosis.

RESULTS

In 12 patients, findings were compatible with erythema nodosum. Six patients had phlebitis or postphlebitic syndrome. Factitial panniculitis was diagnosed in five patients, and trauma had a role in the conditions of another three patients. Cytophagic panniculitis, lymphoma, and leukemia were recognized in one patient each. The lesion was lobular in almost all cases, and the presence of lipophagia was noted in 19 biopsy specimens. Granulomatous, neutrophilic, and lymphocytic pathologic changes were present in nine, eight, and eight tissue specimens, respectively.

CONCLUSION

The recognition of distinct disease patterns of fat lesions as fat necrosis with pancreatic disease, alpha1-antitrypsin panniculitis, lupus and connective tissue disease panniculitis, involution lipoatrophy, lipomembranous panniculitis, factitial panniculitis syndromes, calcification panniculitis, lipophagic lipoatrophy, and cytophagic panniculitis has lessened the need for a less specific panniculitis category. All these diseases have been reported in the literature as "Weber-Christian disease." Because separate and distinct forms of fat lesions have been described, we believe that the eponym should be abandoned and that more specific diagnoses should be made on the basis of pathogenesis or cause.

Multinucleate cell angiohistiocytoma

Multinucleate cell angiohistiocytoma (MCA) is a benign fibrohistiocytic vascular tumor affecting predominantly the acral sites in elderly women. The disorder is often confused clinically and histologically with Kaposi's sarcoma. We report the case of a 63-year-old woman with MCA and describe the main clinical and histopathologic features of this disorder.

Familial Kaposi's sarcoma

Familial cases of Kaposi's sarcoma are exceedingly rare. We identified an 85-year-old man with Kaposi's sarcoma. Multiple lesions were present on the feet. Previously, the man's 84-year-old sister presented with similar lesions on the lower extremity. Both siblings were lifelong residents of the United States and were of English/German descent. Neither had risk factors for infection with human immunodeficiency virus (HIV). On histologic examination, lesions in both patients demonstrated vascular slits, hemorrhage, and dense aggregates of spindle cells within the dermis.

Clinical and histologic spectrum of human T-cell lymphotropic virus type I-associated lymphoma involving the skin

BACKGROUND

Adult T-cell leukemia/lymphoma (ATL) is associated with infection with human T-cell lymphotropic virus type I (HTLV-I).

OBJECTIVE

The objective was to describe the clinical, histopathologic, and immunologic features in three patients with ATL involving the skin.

METHODS

Clinical histories and skin biopsy specimens were reviewed. Immunophenotypic studies were performed on peripheral blood lymphocytes (three patients) and on skin biopsy specimens (one patient).

RESULTS

Serologic testing in each patient was positive for HTLV-I. Specific cutaneous lesions of ATL were diverse. Histologic features included markedly epidermotropic lymphoid infiltrates and dermal aggregates of lymphocytes and macrophages resembling granulomas. One patient died 3 months after diagnosis; the other two are alive with residual lymphoma.

CONCLUSION

A spectrum of clinical, histologic, and immunophenotypic features are seen in ATL involving skin. Those cases with a chronic course may resemble mycosis fungoides clinically and histologically. Serologic testing for HTLV-I is recommended in all patients with cutaneous lymphoma from endemic areas and in those with other risk factors for HTLV-I infection.

The effect of sugar on behavior or cognition in children. A meta-analysis

OBJECTIVE

To examine the effects of sugar on the behavior or cognition of children by using meta-analytic techniques on reported studies.

DATA SOURCES

Studies were identified through a literature search of the MEDLINE and PsychINFO databases and the authors' files using sugar, sucrose, and attention deficit disorder as the search terms.

STUDY SELECTION

Studies were required to (1) intervene by having the subjects consume a known quantity of sugar, (2) use a placebo (artificial sweetener) condition (3) blind the subjects, parents, and research staff to the conditions; and (4) report statistics that could be used to compute the dependent measures effect sizes.

DATA EXTRACTION

Variables included publication year, study setting, subject type and number, gender, age, sugar and placebo type and dose, prior dietary condition, measurement construct, means and SDs for the sugar and placebo conditions, and direction of effect.

DATA SYNTHESIS

Sixteen reports met the inclusion criteria for a total of 23 within-subject design studies. The weighted mean effect size and related statistics for each of the 14 measurement constructs revealed that although the range for these means was from -0.14 for direct observations and up to +0.30 for academic tests, the 95% confidence interval for all 14 mean effect sizes included 0.

CONCLUSION

The meta-analytic synthesis of the studies to date found that sugar does not affect the behavior or cognitive performance of children. The strong belief of parents may be due to expectancy and common association. However, a small effect of sugar or effects on subsets of children cannot be ruled out.

Effect of sugar on behavior and mental performance

Sugar is one of the major dietary components and any relation between sugar and behavior is of major interest. We review the scientific evidence supporting or refuting the relation between sugar and behavior or cognitive function. Little evidence supports the claim that refined sugar intake significantly influences behavior or cognitive performance in children. A few children may have idiosyncratic reactions or rare allergic syndromes and may therefore respond adversely, but this has yet to be substantiated by carefully controlled research. A role for glucose in the potentiation of memory processing appears clear. Further research is required to define the clinical relevance of this role and to elucidate the mechanisms involved. Sucrose may have a sedative effect, at least in infants, but there are no substantial data suggesting that any sugar has analgesic properties.

Relationship between hydrocarbon structure and induction of P450: effect on RNA levels

1. Exposure to simple aromatic hydrocarbons has been shown to induce P450-dependent activities and the expression of particular P450 isozymes in a manner related to the molecular structure of the inducing hydrocarbon. In an attempt to identify the structural relationship controlling P450 induction, the effect of hydrocarbon treatment on the RNA levels for specific P450 isozymes was examined. 2. Rats were treated with daily injections of hydrocarbons (benzene, toluene, ethylbenzene, n-propylbenzene, m- and p-xylene) for 3 days, and the effects on specific RNA levels were examined by Northern blot hybridization. 3. Although P4502B1 mRNA was not elevated after hydrocarbon treatment, a significant elevation in 2B2 mRNA was observed after exposure to the larger aromatic hydrocarbons, ethylbenzene and m-xylene. It is interesting to note that despite the substantial elevation of P4502B protein levels, only a small elevation of P4502B1 and 2B2 RNA was observed. 4. P4502C11 mRNA was only suppressed by ethylbenzene administration, despite the depression of 2C11 protein levels by several hydrocarbons. 5. P4501A1 mRNA was not detectable and 2E1 mRNA was not changed by any aromatic hydrocarbon treatment investigated in this study. 6. The data indicate that the levels of mRNA species for a number of P450 isozymes are differentially regulated by exposure to hydrocarbons, and that small changes in hydrocarbon size or isomeric structure can influence the levels of these mRNA species.

Chilblain lupus erythematosus (lupus pernio): clinical review of the Mayo Clinic experience and proposal of diagnostic criteria

Five cases of chilblain lupus erythematosus were retrospectively reviewed regarding their clinical, histopathologic, serologic, and immunofluorescence findings. Ages at onset of chilblain lupus erythematosus varied from 26 to 73 years, with a female-to-male ratio of 3:2. Since other entities can be confused with this disorder, we propose the following diagnostic criteria. The two major criteria are skin lesions in acral locations induced by exposure to cold or a drop in temperature, and evidence of lupus erythematosus in the skin lesions by results of histopathologic examination or direct immunofluorescence study. The three minor criteria are coexistence of systemic lupus erythematosus or other skin lesions of discoid lupus erythematosus, response to anti-lupus erythematosus therapy, and negative results of cryoglobulin and cold agglutinin studies. We conclude that chilblain lupus erythematosus can be diagnosed and treated. Discoid lupus erythematosus lesions respond more quickly to treatment than chilblain lupus erythematosus lesions. Treatment with antimalarial agents, prednisone, pentoxifylline, or dapsone was of benefit to our patients.

Differences in sodium and D-glucose transport between hamster and rat lungs

The purpose of this study was to characterize phloridzin- and amiloride-sensitive transport across blood-gas barrier of hamster and rat lungs. Air spaces of isolated perfused lungs were instilled with a solution containing 22Na or L-[3H]glucose, D-[14C]glucose, and fluorescein isothiocyanate-labeled dextran. Apparent permeability-surface area products (PS) were calculated. Phloridzin (Na(+)-dependent D-glucose transport inhibitor) had no effect on D-glucose or sodium transport out of air spaces in hamster lungs. In contrast, in rat lungs, phloridzin decreased PS for D-glucose by 89% and that for Na by 28%. Trapping of 14CO2 in vascular samples was measured to estimate metabolism. Unlabeled air space D-glucose increased appearance of perfused D-[14C]glucose in air spaces of rat lungs. We conclude that Na(+)-dependent D-glucose transport is important for D-glucose uptake in rat lungs but not in hamster lungs. In hamster lungs, amiloride (Na+ transport inhibitor) also decreased PS for sodium, but drugs known to stimulate sodium transport in rat lungs had no effect. Thus, species differences in active transport processes exist in the distal air spaces of mammalian lungs.

Subcutaneous T-cell lymphoma. Report of two additional cases and further observations

BACKGROUND

Peripheral T-cell lymphomas involving subcutaneous tissue are rare. With modern immunohistochemical stains, subcutaneous T-cell lymphomas may be demonstrated in patients previously thought to have fatal Weber-Christian disease, malignant histiocytosis, and histiocytic cytophagic panniculitis.

OBSERVATIONS

We describe two young women with subcutaneous lymphomas. They presented with erythematous nodular lesions, which suggested benign panniculitis. Skin biopsy specimens in both patients demonstrated large atypical lymphocytes in the subcutaneous tissue, karyorrhexis, and cytophagia. Immunohistochemical studies confirmed a T-cell phenotype. Molecular genetics studies performed in one patient showed a major T-cell clonal population.

CONCLUSIONS

Subcutaneous T-cell lymphoma is a rare, distinct subtype of postthymic peripheral T-cell lymphoma. Cytophagic "histiocytic" panniculitis is frequently a prominent histologic feature. Early systemic chemotherapy may offer therapeutic advantages in patients with this disease.

Expression analysis of the mixed function oxidase system in rat brain by the polymerase chain reaction

Metabolism of therapeutic drugs in the body by the mixed function oxidase system is an important consideration in the analysis of a drug's effectiveness. P450-dependent metabolism within the brain of a neuro-specific drug may affect the drug's course of action. To determine whether cytochrome P450 was expressed in brain, RNA was isolated from the whole brains of rats treated with a variety of known hepatic P450 inducers, including amitriptyline, imipramine, isosafrole, phenobarbital, and beta-naphthoflavone. The RNA was analyzed for the presence of P450 isozymes by the PCR technique. Differential expression of P450IA1, P450IIB1, P450IIB2, P450IID, and P450IIE1 was detected in the brain samples, depending on the treatment. Cytochrome P450 reductase expression was also detected in the brain samples, giving strong evidence that the brain contains a competent mixed function oxidase system under all conditions studied.

Effects of acyl chain length on the conformation of myelin basic protein bound to lysolipid micelles

The interactions of myelin basic protein with micelles of lysophosphatidylcholine detergents of different acyl chain lengths were investigated by circular dichroism (CD), small-angle X-ray scattering, Fourier transform infrared spectroscopy (FT-IR), and 1H, 13C and 31P nuclear magnetic resonance spectroscopy (NMR). Circular dichroic, FT-IR, and 1H NMR measurements indicated that the conformational changes induced in the protein molecules by association with micelles depended on the acyl chain length of the detergents. Size is one of the physical properties of micelles which is a function of the length of the acyl chains. The radii of gyration of detergent micelles in complexes with the protein measured by small-angle X-ray scattering indicated that the average size of the micelles was a quadratic function of the acyl chain length. The dependence of the protein conformational changes on micelle size was used to ascertain the order in which different protein segments associate with the detergents. Several procedures were employed to change the fluidity of micelles formed with detergents of given acyl chain lengths. The conformational changes observed on the MBP molecule by varying the micelle properties without changing the length of the chain, suggested that the changes depended on the size and fluidity of the micelles.

Physicochemical characterization of dodecylphosphocholine/palmitoyllysophosphatidic acid/myelin basic protein complexes

The stoichiometry of dodecylphosphocholine/palmitoyllysophosphatidic acid/myelin basic protein complexes and the location of the protein in the micelles have been investigated by electron paramagnetic resonance, ultracentrifugation, small-angle X-ray scattering, 31P, 13C, and 1H nuclear magnetic resonance spectroscopy, and electron microscopy. Ultracentrifugation measurements indicated that well-defined complexes are formed by association of one protein molecule with approximately 133 detergent molecules. The spin-labels 5-, 12-, and 16-doxylstearate have been incorporated into detergent/protein aggregates. Electron paramagnetic resonance spectral parameters and 13C and 1H nuclear magnetic resonance relaxation times showed that the addition of myelin basic protein does not affect the environment and location of the labels or the organization of the micelles. Previous results suggesting that the protein lies primarily near the surface of the micelles have been confirmed by comparing 13C spectra of the detergents with and without protein with spectra of detergent/protein aggregates containing the spin labels. Electron micrographs of the complexes taken by using the freeze-fracture technique revealed the presence of particles with an estimated radius about three times the radius of the micelles measured by small-angle X-ray scattering. The structural integrity of the complexes appears to be based on intramolecular protein interactions as well as protein-detergent interactions.

National nosocomial infections surveillance system (NNIS): description of surveillance methods

The National Nosocomial Infections Surveillance System (NNIS) is an ongoing collaborative surveillance system sponsored by the Centers for Disease Control (CDC) to obtain national data on nosocomial infections. The CDC uses the data that are reported voluntarily by participating hospitals to estimate the magnitude of the nosocomial infection problem in the United States and to monitor trends in infections and risk factors. Hospitals collect data by prospectively monitoring specific groups of patients for infections with the use of protocols called surveillance components. The surveillance components used by the NNIS are hospitalwide, intensive care unit, high-risk nursery, and surgical patient. Detailed information including demographic characteristics, infections and related risk factors, pathogens and their antimicrobial susceptibilities, and outcome, is collected on each infected patient. Data on risk factors in the population of patients being monitored are also collected; these permit the calculation of risk-specific rates. An infection risk index, which includes the traditional wound class, is being evaluated as a predictor of the likelihood that an infection will develop after an operation. A major goal of the NNIS is to use surveillance data to develop and evaluate strategies to prevent and control nosocomial infections. The data collected with the use of the surveillance components permit the calculation of risk-specific infection rates, which can be used by individual hospitals as well as national health-care planners to set priorities for their infection control programs and to evaluate the effectiveness of their efforts. The NNIS will continue to evolve in finding more effective and efficient ways to assess the influence of patient risk and changes in the financing of health care on the infection rate.

Multiple keratoacanthomas treated with oral retinoids

Multiple eruptive keratoacanthoma of Witten and Zak is a rare disorder characterized by numerous small, eruptive tumors and larger, more typical keratoacanthomas. Affected patients have features of Grzybowski-type keratoacanthomas and Ferguson Smith type. Two patients with multiple keratoacanthomas were treated with oral retinoids. Both patients had hundreds of follicular papules on the trunk and extremities. Less common lesions included nodules with central horn-filled craters more characteristic of classic keratoacanthomas. Retinoid therapy resulted in regression of the larger, more typical keratoacanthomas in both patients. The small follicular keratoacanthomas remained unaffected. Thus oral retinoids are only partially beneficial for the treatment of the Grzybowski type or the Witten and Zak type of multiple eruptive keratoacanthomas.