Changes in fecal elastase-1 following initiation of CFTR modulator therapy in pediatric patients with cystic fibrosis

BACKGROUND

Improvement in exocrine pancreatic function in persons with CF (pwCF) on cystic fibrosis transmembrane conductance regulator (CFTR) modulators has been documented in clinical trials using fecal pancreatic elastase-1 (FE-1). Our group endeavored to evaluate real-world data on FE-1 in children on CFTR modulator therapy at three pediatric cystic fibrosis (CF) centers.

METHODS

Pediatric pwCF were offered FE-1 testing if they were on pancreatic enzyme replacement therapy (PERT) and on CFTR modulator therapy according to their center's guideline. FE-1 data were collected retrospectively. The primary outcome was absolute change in FE-1.

RESULTS

70 pwCF were included for analysis. 53 had baseline and post-modulator FE-1 values. There was a significant increase in FE-1 from median 25 mcg/g (IQR 25-60) at baseline to 57 mcg/g (IQR 20-228) post-modulator (p<0.001 by Wilcoxon matched pairs), with an absolute change in FE-1 of median 28 mcg/g (IQR -5-161) and mean 93.5 ± 146.8 mcg/g. Age was negatively correlated with change in FE-1 (Spearman r=-0.48, p<0.001). 15 pwCF (21%) had post-modulator FE-1 values ≥200 mcg/g, consistent with pancreatic sufficiency (PS). The PS group was significant for younger age at initiation of first CFTR modulator and a higher baseline FE-1.

CONCLUSIONS

Most pwCF experienced an increase in FE-1 while receiving CFTR modulator treatment and a small percentage demonstrated values reflective of PS. These data suggest that PS may be attained in those that initiated modulator therapy at a younger age or had a higher baseline FE-1. FE-1 testing is suggested for children on any CFTR modulator therapy.

Conceptualization, Operationalization, and Utilization of Race and Ethnicity in Major Epidemiology Journals, 1995-2018: A Systematic Review

Despite repeated calls by scholars to critically engage with the concepts of race and ethnicity in US epidemiologic research, the incorporation of these social constructs in scholarship may be suboptimal. This study characterizes the conceptualization, operationalization, and utilization of race and ethnicity in US research published in leading journals whose publications shape discourse and norms around race, ethnicity, and health within the field of epidemiology. We systematically reviewed randomly selected articles from prominent epidemiology journals across 5 periods: 1995-1999, 2000-2004, 2005-2009, 2010-2014, and 2015-2018. All original human-subjects research conducted in the United States was eligible for review. Information on definitions, measurement, coding, and use in analysis was extracted. We reviewed 1,050 articles, including 414 (39%) in our analyses. Four studies explicitly defined race and/or ethnicity. Authors rarely made clear delineations between race and ethnicity, often adopting an ethnoracial construct. In the majority of studies across time periods, authors did not state how race and/or ethnicity was measured. Top coding schemes included "Black, White" (race), "Hispanic, non-Hispanic" (ethnicity), and "Black, White, Hispanic" (ethnoracial). Most often, race and ethnicity were deemed "not of interest" in analyses (e.g., control variables). Broadly, disciplinary practices have remained largely the same between 1995 and 2018 and are in need of improvement.

What do dental students expect from oral and maxillofacial surgery externships?

INTRODUCTION

Limited information exists on the goals and expectations of dental students from oral and maxillofacial surgery (OMS) externships. This information is valuable to OMS residency programs. Dental students use externships to gain insight into various OMS residency programs.  The purpose of this project was to answer the following question: "what do dental students expect from OMS externships?"

PURPOSE

The aim of this study was to report the expectations of dental students from OMS externships.

MATERIALS AND METHODS

This cross-sectional study took place from June 2015 to September 2019. Every student completing an Emory OMS externship completed an anonymous survey. The survey consisted of questions regarding (1) demographics, (2) previous OMS experience, and (3) open-ended questions regarding expectations and sources of anxiety. Answers were grouped into categories with similar answers. Descriptive statistics summarized data.

RESULTS

Of 116 externs who completed the survey, the majority were males (n = 80, 68.9%) with a mean age of 25 (range 21-30) years old in the 3rd/4th year of dental school. Most had previous OMS experience (n = 103, 89.6%) and plan to apply to OMS residency (n = 104, 90.4%). Most externs hoped to learn about life as a resident and the scope and culture of the program. Externs expressed the highest level of anxiety regarding their own experience and/or knowledge level.

CONCLUSIONS

This project demonstrated that during the externship, externs expect to gain insight into the daily activities, scope, and culture of the OMS program they are visiting.

Opportunities to improve policy dissemination by tailoring communication materials to the research priorities of legislators

BACKGROUND

Communicating research to policymakers is a complex and difficult process. Ensuring that communication materials have information or design aspects that appeal to groups of policymakers with different priorities could be a substantive improvement over current dissemination approaches. To facilitate a more nuanced design of policy communication materials and message framing, we identified and characterized groups of state legislators based on how they prioritize different characteristics of research.

METHODS

We used deidentified data collected in 2012 on 862 state legislators belonging to the US liberal-moderate-conservative ideological spectrum and from all 50 US states. Legislators were grouped using latent class analysis based on how they prioritized 12 different characteristics of research (e.g., research is unbiased, presents data on cost-effectiveness, policy options are feasible). We fit initial models using 1-6 group solutions and chose the final model based on identification, information criteria, and substantive interpretation.

RESULTS

Most legislators placed a high priority on research that was understandable (61%), unbiased (61%), available at the time that decisions are made (58%), and brief and concise (55%). The best model identified four groups of state legislators. Pragmatic consumers (36%) prioritized research that was brief and concise, provided cost-effectiveness analyses, and was understandably written. Uninterested skeptics (30%) generally did not place a high priority on any of the research characteristics. Conversely, one-quarter of legislators (25%) belonged to the Highly Informed Supporters group that placed a high priority on most characteristics of research. Finally, Constituent-Oriented Decision Makers (9%) prioritized research that was relevant to their constituents, delivered by someone they knew or trusted, available at the time decisions were made, and dealt with an issue that they felt was a priority for state legislative action.

CONCLUSIONS

To maximize the impact of dissemination efforts, researchers should consider how to communicate with legislators who have distinct preferences, values, and priorities. The groups identified in this study could be used to develop communication materials that appeal to a wide range of legislators with distinct needs and preferences, potentially improving the uptake of research into the policymaking process. Future work should investigate how to engage skeptical legislators.

A Guide for Choosing Community Detection Algorithms in Social Network Studies: The Question Alignment Approach

INTRODUCTION

Community detection, the process of identifying subgroups of highly connected individuals within a network, is an aspect of social network analysis that is relevant but potentially underutilized in prevention research. Guidance on using community detection methods stresses aligning methods with specific research questions but lacks clear operationalization. The Question Alignment approach was developed to help address this gap and promote the high-quality use of community detection methods.

METHODS

A total of 6 community detection methods are discussed: Walktrap, Edge-Betweenness, Infomap, Louvain, Label Propagation, and Spinglass. The Question Alignment approach is described and demonstrated using real-world data collected in 2013. This hypothetical case study was conducted in 2019 and focused on targeting a hand hygiene intervention to high-risk communities to prevent influenza transmission.

RESULTS

Community detection using the Walktrap method best fit the hypothetical case study. The communities derived using the Walktrap method were quite different from communities derived through the other 5 methods in both the number of communities and individuals within communities. There was evidence to support that the Question Alignment approach can help researchers produce more useful community detection results. Compared to other methods of selecting high-risk groups, the Walktrap produced the most communities that met the hypothetical intervention requirements.

CONCLUSIONS

As prevention research incorporating social networks increases, researchers can use the Question Alignment approach to produce more theoretically meaningful results and potentially more useful results for practice. Future research should focus on assessing whether the Question Alignment approach translates into improved intervention results.

Demographic Groups Likely Affected by Regulating Sugar-Sweetened Beverage Portion Sizes

INTRODUCTION

Sugar-sweetened beverages are a key driver of obesity. Portion-size regulations typically limit the volume of unsealed sugar-sweetened beverage containers to 16 fluid ounces. These regulations could reduce sugar-sweetened beverage consumption, but whom these policies would affect remains unknown. This study evaluates demographic groups likely affected by hypothetical national portion-size regulations modeled on policy language and scopes from New York City and California.

METHODS

Data from adults (aged 18-65 years, n=6,594) in the National Health and Nutrition Examination Survey (2013‒2016) were used to classify individuals as likely affected if they consumed a sugar-sweetened beverage larger than 16 fluid ounces from a potentially regulated food source during at least 1 eating occasion. Two classifications of affected food sources were evaluated: (1) excluding convenience stores (New York City scope) and (2) including convenience stores (California scope). In 2020, analyses were conducted using logistic regression to examine associations between affected status and age (<35 and ≥35 years), sex, race/ethnicity (white, non-Hispanic, black, non-Hispanic, andHispanic), education (without college degree and with college degree), and income (≤185% and >185% of the federal poverty line).

RESULTS

Portion-size regulations would affect 8.87% of adults (New York City scope) and 14.71% of adults (California scope). Regulations had a greater potential effect on adults who were aged <35 years, male, and without a college degree (all p<0.05). Differences between demographic groups would be larger in magnitude using California's policy scope.

CONCLUSIONS

Portion-size regulations would likely have a greater effect on younger, male, and less-educated adults. Policy effects would likely be larger if these regulations are written to encompass more food sources.

Social Influences on Obesity: Current Knowledge, Emerging Methods, and Directions for Future Research and Practice

PURPOSE OF REVIEW

Individuals tend to be socially connected with those of similar weight and obesity status. To inform future research and intervention development, we reviewed recent literature examining social influences on weight with a focus on mechanisms of social influence, populations studied, and emerging analytical methods.

RECENT FINDINGS

Social networks appear to influence weight gain and weight loss. It remains unclear what underlying mechanisms (e.g., social norms, social comparison, behavioral modeling) drive this relationship. Stochastic actor-oriented modeling is an important method in the field, but other work has leveraged natural experiment or randomized designs to study social influence. Future networks and obesity research should examine social influence mechanisms, focus on diverse populations across the life course, and carefully consider how to adequately control for competing factors of social selection and physical environments.

Childhood Misfortune and Handgrip Strength Among Black, White, and Hispanic Americans

OBJECTIVE

Although early-life insults may affect health, few studies use objective physical measures of adult health. This study investigated whether experiencing misfortune during childhood is associated with handgrip strength (HGS) in later life.

METHOD

Data on childhood misfortune and adult characteristics from the Health and Retirement Study were used to predict baseline and longitudinal change in HGS among White, Black, and Hispanic American men and women.

RESULTS

Regression analyses revealed that multiple indicators of childhood misfortune were related to HGS at baseline, but the relationships were distinct for men and women. Over the study, having one childhood impairment predicted steeper declines in HGS for men, but childhood misfortune was unrelated to HGS change among women. Hispanic Americans had lower baseline HGS than their non-Hispanic counterparts and manifested steeper declines in HGS.

DISCUSSION

The relationship between childhood exposures and adult HGS varied by the type of misfortune, but there was no evidence that the relationship varied by race/ethnicity. The significant and enduring Hispanic disadvantage in HGS warrants greater attention in gerontology.

Weight-related quality of life and temperament as predictors and moderators of outcomes among treatment-seeking, low-income, ethnically diverse children with obesity

Within any childhood obesity treatment program, some children have better outcomes than others. Little is known about predictors or moderators of more positive outcomes. We aimed to identify whether child temperament and weight-related quality of life predict or moderate childhood obesity treatment outcomes at 6 months. From 2015 to 2016, children (n = 97) ages 5-11 years old with obesity were randomized to a clinic-community (Bull City Fit) or a clinic-only treatment program. Linear regression was used to explore whether dimensions of child temperament and weight-related quality of life predicted or moderated 6-month anthropometric and physical activity outcomes. Children who had more social avoidance due to their weight at baseline had significantly better improvements in body fat percent in the clinic-community model compared with the clinic-only model at 6 months. Across programs, better baseline social quality of life predicted greater increases in waist circumference; conversely, better physical quality of life predicted a decrease in percent of the 95th percentile. Also, children with longer attention spans had greater increases in physical activity. Our findings suggest that children who have social avoidance due to their weight may benefit most from comprehensive clinic-community treatment. Weight-related quality of life may influence outcomes across all treatments, and practitioners need to carefully counsel children experiencing weight negatively.

A scoping review of simulation modeling in built environment and physical activity research: Current status, gaps, and future directions for improving translation

Existing reviews have suggested that simulation studies of physical activity and environments are an emerging area, but none have explored findings in this area systematically. We used a scoping review framework to assess the use of simulation modeling to inform decision-making about built environment influences on physical activity. A systematic literature search was conducted in multiple databases in January 2018. Sixteen articles met the inclusion criteria. The studies evaluated interventions and features that were related to neighborhood safety (crime or traffic), active transportation, land use design, and walking and biking infrastructure. All of the studies focused on urban areas and most considered heterogeneity of outcomes based on local context. The majority of studies (70%) did not appear to have engaged or been used by practitioners or policy-makers to inform real-world decisions. There has been a growth of simulation modeling studies, but there remain gaps. The studies evaluated built environment interventions that have been recommended by expert panels, but more were of interventions related to active transportation; few considered recommended interventions to support recreational activity. Furthermore, studies have all focused on urban settings and there is a need to consider non-urban settings and how heterogeneity could reduce or exacerbate health disparities. More work to involve and evaluate practices for engaging stakeholders in model development and interpretation is also needed to overcome the translation of simulation research to practice gap, and realize its potential impact on the built environment and physical activity.

A randomized, open-label study of the efficacy and safety of AZD4547 monotherapy versus paclitaxel for the treatment of advanced gastric adenocarcinoma with FGFR2 polysomy or gene amplification

Background

Approximately 5%-10% of gastric cancers have a fibroblast growth factor receptor-2 (FGFR2) gene amplification. AZD4547 is a selective FGFR-1, 2, 3 tyrosine kinase inhibitor with potent preclinical activity in FGFR2 amplified gastric adenocarcinoma SNU16 and SGC083 xenograft models. The randomized phase II SHINE study (NCT01457846) investigated whether AZD4547 improves clinical outcome versus paclitaxel as second-line treatment in patients with advanced gastric adenocarcinoma displaying FGFR2 polysomy or gene amplification detected by fluorescence in situ hybridization.

Patients and methods

Patients were randomized 3:2 (FGFR2 gene amplification) or 1:1 (FGFR2 polysomy) to AZD4547 or paclitaxel. Patients received AZD4547 80 mg twice daily, orally, on a 2 weeks on/1 week off schedule of a 21-day cycle or intravenous paclitaxel 80 mg/m2 administered weekly on days 1, 8, and 15 of a 28-day cycle. The primary end point was progression-free survival (PFS). Safety outcomes were assessed and an exploratory biomarker analysis was undertaken.

Results

Of 71 patients randomized (AZD4547 n = 41, paclitaxel n = 30), 67 received study treatment (AZD4547 n = 40, paclitaxel n = 27). Among all randomized patients, median PFS was 1.8 months with AZD4547 and 3.5 months with paclitaxel (one-sided P = 0.9581); median follow-up duration for PFS was 1.77 and 2.12 months, respectively. The incidence of adverse events was similar in both treatment arms. Exploratory biomarker analyses revealed marked intratumor heterogeneity of FGFR2 amplification and poor concordance between amplification/polysomy and FGFR2 mRNA expression.

Conclusions

AZD4547 did not significantly improve PFS versus paclitaxel in gastric cancer FGFR2 amplification/polysomy patients. Considerable intratumor heterogeneity for FGFR2 gene amplification and poor concordance between FGFR2 amplification/polysomy and FGFR2 expression indicates the need for alternative predictive biomarker testing. AZD4547 was generally well tolerated.

"I don't know how I'm still standing" a Bakhtinian analysis of social housing and health narratives in East London

Housing is a significant determinant of health and substandard housing is a public health issue. East London has long had a shortage of social and affordable housing, worsened in recent years by a combination of stressors. In one of East London's most deprived boroughs, Newham, changes brought about by the 2011 Localism Act and the unique demands of being the host Olympic borough in 2012 have brought considerable pressures to bear on social infrastructure. This paper examines how these pressures were experienced by local residents via their narratives of social housing and health. The data reported here are from a qualitative study comprising two waves of data collection. Narrative family interviews and go-along interviews were conducted with 40 Newham residents at wave one and 28 at wave two. A narrative analysis with a Bakhtinian interpretation was undertaken. This revealed that residents framed experiences of social housing in terms of an inherent system-level ideology based on notions of need and waiting. A particularly striking feature of this ideology was the extent to which descriptions of ill health and impairment were implicated in constructions of housing need; participants directly attributed a range of health complaints to their housing predicaments, including stress, depression, cancer scares, panic attacks and loss of sleep. Understanding the contested ideology of social housing can illuminate both the dynamic processes of social exclusion and the ways in which its subjects seek to resist it.

Associations between birth weight and colon and rectal cancer risk in adulthood

BACKGROUND

Birth weight has inconsistent associations with colorectal cancer, possibly due to different anatomic features of the colon versus the rectum. The aim of this study was to investigate the association between birth weight and colon and rectal cancers separately.

METHODS

193,306 children, born from 1936 to 1972, from the Copenhagen School Health Record Register were followed prospectively in Danish health registers. Colon and rectal cancer cases were defined using the International Classification of Disease version 10 (colon: C18.0-18.9, rectal: 19.9 and 20.9). Only cancers classified as adenocarcinomas were included in the analyses. Cox regressions were used to estimate hazard ratios (HR) and 95% confidence intervals (CI). Analyses were stratified by birth cohort and sex.

RESULTS

During 3.8 million person-years of follow-up, 1465 colon and 961 rectal adenocarcinomas were identified. No significant sex differences were observed; therefore combined results are presented. Birth weight was positively associated with colon cancers with a HR of 1.14 (95% CI, 1.04-1.26) per kilogram of birth weight. For rectal cancer a significant association was not observed for birth weights below 3.5kg. Above 3.5kg an inverse association was observed (at 4.5kg, HR=0.77 [95% CI, 0.61-0.96]). Further, the associations between birth weight and colon and rectal cancer differed significantly from each other (p=0.006).

CONCLUSIONS

Birth weight is positively associated with the risk of adult colon cancer, whereas the results for rectal cancer were inverse only above values of 3.5kg. The results underline the importance of investigating colon and rectal cancer as two different entities.

Use of existing water, sediment, and tissue data to screen ecological risks to the endangered Rio Grande silvery minnow

A screening-level ecological risk assessment was applied to two extensive, but previously unanalyzed datasets from the middle Rio Grande (MRG) in New Mexico. The assessment evaluated how adverse water-quality effects from aquatic toxicants may have influenced the population decline of the endangered Rio Grande silvery minnow (Hybognathus amarus; silvery minnow). Standardized US Environmental Protection Agency (USEPA) screening-level ecological risk assessment procedures were applied to chemicals assessed in samples collected from the MRG between 1985 and 2003. Since more chemicals have established risk-screening criteria, relative to water-quality criteria, this approach produces more complete assessments. Chemical concentrations at some locations and times were potentially sufficient to affect fish health or produce localized mortalities. Many constituents displaying the highest risks have substantial natural sources within the watershed; native species likely would have adapted to natural instream concentrations such that actual risks might be markedly less than projected by a risk screening based on generic aquatic-life criteria. Also, highest risks found for individual and combinations of contaminants were very inconsistent both within and across the sites. As such, this risk assessment does not support the conclusion that toxicants were a primary factor causing the silvery minnow population to decline in the MRG between 1985 and 2003. The assessment indicates that sediment-borne, relative to water-borne, contaminants appeared to present the greatest risks to the silvery minnow and thus should have increased focus during future assessments of potential contaminant effects in the MRG. Contaminants of greatest concern are identified. This study presents approaches to cost-effectively assess and reduce uncertainties associated with potential water quality effects, and to help direct future assessments of water quality onto those contaminants likely to produce potentially significant effects. The techniques presented and criteria compiled are suitable for aiding similar assessments in other aquatic habitats.

Intraoperative administration of inhaled carbon monoxide reduces delayed graft function in kidney allografts in Swine

Ischemia/reperfusion injury and delayed graft function (DGF) following organ transplantation adversely affect graft function and survival. A large animal model has not been characterized. We developed a pig kidney allograft model of DGF and evaluated the cytoprotective effects of inhaled carbon monoxide (CO). We demonstrate that donor warm ischemia time is a critical determinant of DGF as evidenced by a transient (4-6 days) increase in serum creatinine and blood urea nitrogen following transplantation before returning to baseline. CO administered to recipients intraoperatively for 1 h restored kidney function more rapidly versus air-treated controls. CO reduced acute tubular necrosis, apoptosis, tissue factor expression and P-selectin expression and enhanced proliferative repair as measured by phosphorylation of retinol binding protein and histone H3. Gene microarray analyses with confirmatory PCR of biopsy specimens showed that CO blocked proinflammatory gene expression of MCP-1 and heat shock proteins. In vitro in pig renal epithelial cells, CO blocks anoxia-reoxygenation-induced cell death while promoting proliferation. This large animal model of DGF can be utilized for testing therapeutic strategies to reduce or prevent DGF in humans. The efficacy of CO on improving graft function posttransplant validates the model and offers a potentially important therapeutic strategy to improve transplant outcomes.

Clinical pearl: a method of controlled movement of teeth using open and closed coil spring

A method of controlled movement of teeth using open and closed coil spring. A 'clinical pearl' describing an original clinical technique to prevent uncontrolled tooth movement while using an active coil spring on the archwire.

Inhibiting vascular endothelial growth factor receptor-2 signaling reduces tumor burden in the ApcMin/+ mouse model of early intestinal cancer

The Apc(Min/+) mouse model is a clinically relevant model of early intestinal cancer. We used AZD2171, an oral, highly potent and selective vascular endothelial growth factor (VEGF) signaling inhibitor, to investigate the role of VEGF receptor-2 (VEGFR-2) signaling in adenoma development and growth in Apc(Min/+) mice. AZD2171 (5 mg/kg body wt/day) was administered once daily for 28 days to 6-week-old (early-intervention) or 10-week-old (late intervention) mice. In the early-intervention study, AZD2171 reduced the number of macroscopic polyps in the small bowel and colon. Macropolyp diameter was lower in the small bowel, but remained unchanged in the colon. In animals receiving AZD2171, microscopic evaluation of the small intestine showed a significant reduction in the number of larger lesions. In the late-intervention study, AZD2171 treatment reduced macropolyp diameter (but not number) in the small intestine. Microscopic analysis revealed that AZD2171 significantly reduced the number of larger micropolyps in the small bowel, with no large micropolyps present in the colon. AZD2171 treatment had no effect on microvessel density or localization of beta-catenin staining in adenomas or non-tumor intestinal tissue, but significantly reduced the number of cells expressing VEGFR-2 mRNA. In conclusion, the effects of AZD2171 in the small intestine of Apc(Min/+) mice are consistent with an antiangiogenic mechanism of action, limiting growth of adenomas to < or =1 mm. These data also suggest that an early step in adenoma development may depend on VEGFR-2 signaling. Together, these results indicate that VEGFR-2 signaling may play key roles in the development and progression of intestinal adenomas.

Modulation of proteoglycan and collagen profiles in human dermal fibroblasts by high density micromass culture and treatment with lactic acid suggests change to a chondrogenic phenotype

Cartilage formation during embryonic development and in fracture healing in adult animals involves chondrogenic differentiation of mesenchymal precursors. Here we describe an in vitro model whereby human dermal fibroblasts, considered to be restricted to a fibroblast lineage, are apparently redirected toward a chondrogenic phenotype by high density micromass culture in the presence of lactic acid. Micromass cultures treated with 40 mM lactate exhibited increased levels of Alcian blue staining and sulfate incorporation, indicative of elevated sulfated glycosaminoglycan synthesis. Northern analysis revealed an up-regulation of chondroitin sulfate proteoglycan 1 (aggrecan) and transforming growth factor-beta 1 mRNA and a decrease in type I collagen expression. Type II collagen was detected by reverse transcription-PCR only in experimental cultures. Although the observed changes in biosynthesis and gene expression were consistent with differentiating chondrocytes, the cells displayed an elongated, fibroblast-like morphology. These findings suggest that dermal fibroblasts may be committed to differentiate along a chondrogenic pathway by in vitro culture under specific forcing conditions.

Morphologic characterization of the ice worm Mesenchytraeus solifugus

Ice worms occupy a unique position in metazoan phylogeny in that they are the only known annelid that completes its life cycle in ice. The mechanism(s) associated with this adaptation are likely to occur at different levels, ranging from modification of their metabolism to changes in morphology. In this study, we examined specimens of Mesenchytraeus solifugus by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) in an effort to identify morphologic structures that may aid in its glacial habitation. We report that M. solifugus contains an elongated head pore at the tip of its prostomium, numerous sensory structures, and differentially oriented setae that curve abruptly at their distal end.

Vertebrate pseudogenes

Pseudogenes are commonly encountered during investigation of the genomes of a wide range of life forms. This review concentrates on vertebrate, and in particular mammalian, pseudogenes and describes their origin and subsequent evolution. Consideration is also given to pseudogenes that are transcribed and to the unusual group of genes that exist at the interface between functional genes and non-functional pseudogenes. As the sequences of different genomes are characterised, the recognition and interpretation of pseudogene sequences will become more important and have a greater impact in the field of molecular genetics.

Rapid determination of the complexity of cDNA bands extracted from DDRT-PCR polyacrylamide gels

A band extracted from a differential display polyacrylamide gel often represents a composite of heterogeneous products. We have developed a non- radioactive method to simply and rapidly analyse its complexity. A fluorescent restriction enzyme fingerprint of the composite mixture is generated. The number of individual bands observed in this fingerprint indicates the complexity of the re-amplified cDNA mixture. Restriction fingerprints of the inserts of cDNA subclones derived from the re-amplified cDNA mixture are compared to the composite fingerprint to select those representing the most intense bands in the composite. This dramatically reduces the number of clones required for further characterisation.

Automated differential display using a fluorescently labeled universal primer

We have modified the automated differential display reverse transcription polymerase chain reaction technique (DDRT-PCR) such that a single fluorescently labeled universal primer (d(F)CTCACG-GATCCGTCGATTTT) is used in all PCRs together with a selection of arbitrary primers. We term this fluorescent detection procedure FDDRT-PCR. Anchoring primers of general structure dTGGTCTCACGGATCCTCGA-(T)12 VN (where N can be any deoxynucleoside and V can be any deoxynucleoside other than thymidine) are used for the RT step, and the universal primer together with selected arbitrary primers are then used for the PCR amplification. Advantages of this approach are: (i) the fluorescently labeled universal primer is a constant feature in every PCR, so that changes in banding profile are highly likely to reflect the incorporation of different arbitrary 10-mer primers; (ii) artifacts that result from arbitrary 10-mer to arbitrary 10-mer primer amplifications are not observed by fluoresence detection on an automated gene scanner because such products are not fluorescently labeled; (iii) sample throughput and ease of data handling are increased when compared with the conventional radioactive/manual approach and (iv) using a single fluorescently labeled primer in all PCRs is highly cost-effective.

Common BRCA1 variants and susceptibility to breast and ovarian cancer in the general population

Most multiple case families of young onset breast cancer and ovarian cancer are thought to be due to highly penetrant mutations in the predisposing genes BRCA1 and BRCA2. However, these mutations are uncommon in the population and they probably account for only a few percent of all breast cancer incidence. A much larger fraction of breast cancer might, in principle, be due to common variants which confer more modest individual risks. There are several common polymorphisms in the BRCA1 gene which generate amino acid substitutions. We have examined the frequency of four of these polymorphisms: Gln356Arg, Pro871Leu, Glu1038Gly and Ser1613Gly in large series of breast and ovarian cancer cases and matched controls. Due to strong linkage disequilibrium, these four sites generate only three haplotypes with a frequency > 1.3%. The most common haplotypes, defined by the alleles Gln356Pro871Glu1038Ser1613 and Gln356Leu871Gly1038Gly1613, have frequencies of 0.57 and 0.32 respectively, and these frequencies do not differ significantly between patient and control groups. Thus the most common polymorphisms of the BRCA1 gene do not make a significant contribution to breast or ovarian cancer risk. However, our data suggest that the Arg356 allele may have a different genotype distribution in breast cancer patients from that in controls (Arg356 homozygotes are more frequent in the control groups, P = 0.01), indicating that it may be protective against breast cancer. If this finding can be confirmed, it may provide an insight into the structural features of the BRCA1 protein that are important for its function.

Bioavailability of selenium accumulated by selenite-reducing bacteria

The bioavailability of selenium (Se) was determined in bacterial strains that reduce selenite to red elemental Se (SeO). A laboratory strain of Bacillus subtilis and a bacterial rod isolated from soil in the vicinity of the Kesterson Reservoir, San Joaquin Valley, CA, (Microbacterium arborescens) were cultured in the presence of 1 mM sodium selenite (Na2SeO3). After harvest, the washed, lyophilized B. Subtilis and M. arborescens samples contained 2.62 and 4.23% total Se, respectively, which was shown to consist, within error, entirely of SeO. These preparations were fed to chicks as supplements to a low-Se, vitamin E-free diet. Three experiments showed that the Se in both bacteria had bioavailabilities of approx 2% that of selenite. A fourth experiment revealed that gray SeO had a bioavailability of 2% of selenite, but that the bioavailability of red SeO depended on the way it was prepared (by reduction of selenite). When glutathione was the reductant, bioavailability resembled that of gray SeO and bacterial Se; when ascorbate was the reductant, bioavailability was twice that level (3-4%). These findings suggest that aerobic bacteria such as B. subtilis and M. arborescens may be useful for the bioremediation of Se-contaminated sites, i.e., by converting selenite to a form of Se with very low bioavailability.

Physiological mechanisms regulating the conversion of selenite to elemental selenium by Bacillus subtilis

We have demonstrated that the common soil bacterium, Bacillus subtilis, reduces selenite to an insoluble and much less toxic product--the red form of elemental selenium. Reduction was effected by an inducible system that appears to deposit elemental selenium between the cell wall and the plasma membrane. Glucose and sucrose supported selenite reduction. Although malate and citrate supported growth, no significant reduction of selenite occurred, indicating the importance of the redox state of the culture substrate. Selenite reduction in the millimolar concentration range (i.e., cultures supplemented with 1 mM selenite) was not affected by a ten-fold excess of nitrate or sulfate--compounds that serve as alternate electron acceptors and antagonize selenite reduction by anaerobic bacteria. Similarly, nitrite and sulfite did not significantly affect the rate or extent of selenite reduction. B.subtilis was able to grow and produce selenium (Se degree) at selenite concentrations ranging from 0.6 microM to 5 mM (50 ppb to 395 ppm selenium). At the lowest selenite concentration tested, 50 ppb selenium, B.subtilis removed 95% of the selenite from the liquid phase. The results suggest that selenite is reduced via an inducible detoxification system rather than dissimilatory electron transport. The findings establish the potential utility of B.subtilis for the bioremediation of selenite-polluted sites.

A comparison of three bracket bases: an in vitro study

The purpose of this study was to evaluate the differences in mean tensile bond strength between three groups of orthodontic bracket bases; coarse mesh (Dentaurum), fine mesh (A-Company), and an undercut base (Dynalok). Due to microscopic differences seen in the course mesh bases, these were further sub-divided into rough, smooth, and defective mesh groups, and tested in a double blind trial. All brackets were bonded to plastic cylinders with a highly filled composite resin (Concise) and tested to failure on an Instron universal testing machine. No significant differences in mean tensile bond strength were seen between the rough, smooth, and defective coarse mesh bases. The fine mesh base showed significantly higher mean tensile bond strength compared with the coarse. Both meshes performed significantly better than the undercut base.

Characterization of the binding of Pseudomonas aeruginosa alginate to human epithelial cells

The alginate produced by Pseudomonas aeruginosa has been reported to play a role in the adhesion of this bacterium to epithelial cell surfaces, although some controversy concerning this role exists. To clarify this controversy, we investigated the ability of alginate to bind to human buccal epithelial cells (BECs) and human tracheal epithelial cells (TECs). Alginate from P. aeruginosa 492c bound to both BECs and TECs. Alginate from strain 492c was found to be multivalent and thus capable of agglutinating both BECs and TECs. The multivalency of alginate complicated the determination of the number of alginate-specific receptors on the BEC and the apparent association constant (Ka). By using the analysis of Hogg and Winzor (Biochim. Biophys. Acta 843:159-163, 1985), an average valency of 2.6 BEC binding domains per alginate molecule was determined, and the maximum binding capacity per BEC was calculated to be 5.8 X 10(-4) micrograms, with a Ka of 4.1 X 10(-2) ml/micrograms. The binding of alginate to immobilized BECs (where only 50% of the BEC surface is exposed) yielded values of 2.52 X 10(-4) micrograms of alginate per BEC for the maximum binding capacity per BEC and a Ka of 3.30 X 10(-2) ml/micrograms. The alginate-specific site on the BEC surface was trypsin sensitive. Alginate from P. aeruginosa 492a did not bind to BECs, differing substantially from that of strain 492c. The data presented here demonstrate that alginate purified from some strains of P. aeruginosa may bind to TECs and BECs in a defined, specific manner, whereas alginate from other strains does not, reflecting structural diversity in P. aeruginosa alginates.

The relationships between volition, activity pattern, and life satisfaction in the elderly

This study examines the relationships between the volition subsystem, activity pattern, and life satisfaction of 60 elderly individuals. The volition subsystem includes an individual's interests, values, and personal causation. The Occupational Questionnaire (OQ) was developed to measure volition subsystems and activity patterns, and it was pilot tested for reliability and validity. Scores on the OQ were compared with measures of subjects' life satisfaction. Results of the study identified several aspects of the subjects' occupations that were related to their level of life satisfaction. The most important findings were the positive correlations between the degree of interest, value, and personal causation in occupation and life satisfaction. Time spent in work and leisure was found to be correlated more highly with high levels of life satisfaction than was time spent in daily living tasks and rest. Although further verification of these results is needed, these findings indicate that occupational therapists may enhance the life satisfaction of their elderly patients by emphasizing interests, values, personal causation, work, and leisure in their treatment programs.

An x-ray microanalysis study of differences in concentration of elements in brain cells due to opiates, cell type, and subcellular location

Adult female Sprague Dawley rats were divided into three groups and given two daily doses of: 1) morphine (25 mg/kg at each injection), or 2) methadone (5 mg/kg), or 3) saline for nine days. Two hours before the rats were killed on day 10, they were given a double dose of the drugs. Fifteen minutes before being killed, some of the morphine-treated rats were given the opiate antagonist naloxone (2.5 mg/kg), which caused a sudden arousal in these rats. At the time of killing, the preoptic-hypothalamic region was repidly removed and frozen in liquid propane to prevent translocation of elements in cells. Frozen 4-micrometer sections were cut, freeze-dried, and electron-probed in a scanning electron microscope, and energy-dispersive x-ray spectra were collected. The characteristic peak-to-continuum ratio for all detectable elements was determined in both the nucleus and the cytoplasm of ependymal cells and neurons. The data from nine cells of each type in each rat brain were then subjected to one- and three-way analysis of variance. The results show significant differences in the distribution of elements (sodium, magnesium, phosphorus, sulfur, chlorine, potassium, and calcium) which are dependent upon: 1) subcellular localization, 2) cell type, and particularly, 3) opiate treatment. The behavioral state produced by the opiates is correlated with the effects they have on intracellular concentration of several elements, most notably, sodium.

Concentration of elements in mitotic chromatin as measured by x-ray microanalysis

Unfixed frozen-dried and uncoated tissue sections of the mouse duodenum were placed on carbon planchets and analyzed in a scanning electron microscope fitted with energy dispersive X-ray equipment. Computer analysis of the X-ray spectra allowed elemental microanalysis of the nucleus, cytoplasm, and mitotic chromatin regions in the cryptal and villus enterocytes. The peak to continuum ratio of S, Cl, K, and Ca were higher in mitotic chromatin than any of the other sites measured. The redistribution of Ca at mitosis is postulated to help explain both chromosome condensation and assembly of the mitotic spindle apparatus.

A Note on the so-called "Disuse" Atrophy of Muscle

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Congenital Absence of Tibia

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