Plate and screw fixation is a recent addition to the sternal wound treatment armamentarium. Patients undergoing cardiac and major vascular surgery have a higher risk of postoperative arrest than other elective patients. Those who undergo sternotomy for either cardiac or major vascular procedures are at a higher risk of postoperative arrest. Sternal plate design allows quick access to the mediastinum facilitating open cardiac massage, but chest compressions are the mainstay of re-establishing cardiac output in the event of arrest. The response of sternal plates and the chest wall to compressions when plated has not been studied. The safety of performing this maneuver is unknown. This study intends to demonstrate compressions are safe after sternal plating.
We investigated the effect of chest compressions on the plated sternum using a human cadaveric model. Cadavers were plated, an arrest was simulated, and an experienced physician performed a simulated resuscitation. Intrathoracic pressure was monitored throughout to ensure the plates encountered an appropriate degree of force. The hardware and viscera were evaluated for failure and trauma respectively.
No hardware failure or obvious visceral trauma was observed. Rib fractures beyond the boundaries of the plates were noted but the incidence was comparable to control and to the fracture incidence after resuscitation previously cited in the literature.
From this work we believe chest compressions are safe for the patient with sternal plates when proper plating technique is used. We advocate the use of this life-saving maneuver as part of an ACLS resuscitation in the event of an arrest for rapidly re-establishing circulation.
Controversy surrounds the expression of α7 nicotinic acetylcholine receptors (nAChRs) in adrenal chromaffin cells. In these studies, α7 nAChRs expressed in bovine adrenal chromaffin cells are investigated. Using radiolabeled ligand binding techniques, [125I]α-bungarotoxin (αBGT) binding reaches equilibrium within 4 hours and is saturable with a Kd value of 4.2 nM. Using homologous competition experiments, the Ki for binding of αBGT was 1.9 nM. These data are consistent with the expression of homomeric α7 nAChRs. Methyllycaconatine (MLA), which binds α7 nAChRs with high affinity, inhibits [125I]αBGT binding in a concentration-dependent manner with a Ki of 30.6 nM; this value is ∼10 fold higher than the reported affinity of MLA for α7 nAChRs. We also document the ability of bromoacetylcholine (brACh) to alkylate α7 nAChRs, as has been previous demonstrated for bovine adrenal α3β4 nAChRs. When adrenal nAChRs are immunoprecipated with mAb 319, an antibody which recognizes α7 nAChR protein, and then probed with mAb 319 using Western blot analysis, a single band of ∼53 kD is identified. When adrenal nAChRs are immunoprecipated with mAb35, an antibody which recognizes α3 and α5 nAChR proteins, and then probed with mAb319 using Western blot analysis, a single band of ∼53 kD is identified. Together, these results support the expression of α7 nAChRs in bovine adrenal chromaffin cells. However, these data suggest that the subunit composition of some of these receptors may include heteromeric α7 nAChRs.
Nicotinic acetylcholine receptor; binding; adrenal medulla; methyllycaconitine; α-bungarotoxin; α7
Previous research has shown that ideas which violate our expectations, such as schema-inconsistent concepts, enjoy privileged status in terms of memorability. In our study, memory for concepts that violate cultural (cultural schema-level) expectations (e.g., “illiterate teacher”, “wooden bottle”, or “thorny grass”) versus domain-level (ontological) expectations (e.g., “speaking cat”, “jumping maple”, or “melting teacher”) was examined. Concepts that violate cultural expectations, or counter-schematic, were remembered to a greater extent compared with concepts that violate ontological expectations and with intuitive concepts (e.g., “galloping pony”, “drying orchid”, or “convertible car”), in both immediate recall, and delayed recognition tests. Importantly, concepts related to agents showed a memory advantage over concepts not pertaining to agents, but this was true only for expectation-violating concepts. Our results imply that intuitive, everyday concepts are equally attractive and memorable regardless of the presence or absence of agents. However, concepts that violate our expectations (cultural-schema or domain-level) are more memorable when pertaining to agents (humans and animals) than to non-agents (plants or objects/artifacts). We conclude that due to their evolutionary salience, cultural ideas which combine expectancy violations and the involvement of an agent are especially memorable and thus have an enhanced probability of being successfully propagated.
While it is known that community-based outpatient treatment for substance abusing offenders is effective, treatment completion rates are low and much of the prior research has been conducted with offenders in residential treatment or therapeutic communities. The aim of the present study was to assess whether offenders who are mandated to community-based outpatient treatment have better completion rates compared to those who enter treatment voluntarily. The 160 research participants were a heterogeneous group of substance abusers who were under various levels of criminal justice supervision (CJS) in the community. The participants were enrolled in an intensive outpatient program and were recruited into the study between July 2007 and October 2010. All offenders received weekly therapy sessions using a cognitive problem solving framework and 45% completed the six month treatment program. Interestingly, those who were mandated demonstrated less motivation at treatment entry, yet were more likely to complete treatment compared to those who were not court-ordered to treatment. While controlling for covariates known to be related to treatment completion, the logistic regression analyses demonstrated that court-ordered offenders were over ten times more likely to complete treatment compared to those who entered treatment voluntarily (OR = 10.9, CI = 2.0–59.1, p = .006). These findings demonstrate that stipulated treatment for offenders may be an effective way to increase treatment compliance.
Treatment completion; criminal justice; offenders; substance abusers
Overweight youth have greater bone mass than their healthy-weight peers but sustain more fractures. However, it is unclear whether and how excess body fat influences bone quality in youth.
We determined whether overweight status correlated with three-dimensional aspects of bone quality influencing bone strength in adolescent and young adult females and males.
We categorized males (n = 103; mean age, 17 years) and females (n = 85; mean age, 18 years) into healthy-weight and overweight groups. We measured lean mass (LM) and fat mass (FM) with dual-energy x-ray absorptiometry (DXA). We used high-resolution peripheral quantitative CT to assess the distal radius (7% site) and distal tibia (8% site). Bone quality measures included total bone mineral density (Tt.BMD), total area (Tt.Ar), trabecular bone volume fraction (BV/TV), trabecular number (Tb.N), separation (Tb.Sp), and thickness (Tb.Th). We used multiple regression to compare bone quality between healthy-weight and overweight adolescents adjusting for age, ethnicity, limb length, LM, and FM.
Overweight males had higher (10%–21%) Tt.BMD, BV/TV, and Tb.N and lower Tb.Sp at the tibia and lower Tt.Ar at the radius than healthy-weight males. No differences were observed between overweight and healthy-weight females. LM attenuated the differences in bone quality between groups in males while FM negatively predicted Tt.BMD, BV/TV, Tb.N, and Tb.Th.
Our data suggest overweight males have enhanced bone quality compared with healthy-weight males; however, when group differences are interpreted in the context of the mechanostat theory, it appears bone quality of overweight adolescents adapts to LM and not to greater FM.
This project developed and tested a 17-item monitoring instrument covering important substance use related behaviors to support measurement-based care and outcomes assessment. The study consisted of two phases, an instrument development phase and an initial study to examine its psychometric properties. Participants were 175 patients entering VA outpatient substance abuse treatment. The findings revealed that this Brief Addiction Monitor (BAM) exhibited acceptable characteristics. Exploratory factor analysis yielded three summary factors; Recovery Protection, Physical & Psychological Problems, and Substance Use & Risk. The RMSEA estimate was acceptable and the factors had alpha values exceeding or approaching 0.70. All three factors were sensitive to change and had excellent test-retest reliability. Predictive validity was demonstrated for two factors, Recovery Protection and Substance Use & Risk. At the item level, there was little indication of inappropriate response patterns. Change over time was significant for most items, and test-retest reliability was acceptable for nearly all items. Additional research is warranted to further establish the BAM’s reliability, validity and usefulness.
Breast cancer is the most common cancer among women. Common variants at 27 loci have been identified as associated with susceptibility to breast cancer, and these account for ~9% of the familial risk of the disease. We report here a meta-analysis of 9 genome-wide association studies, including 10,052 breast cancer cases and 12,575 controls of European ancestry, from which we selected 29,807 SNPs for further genotyping. These SNPs were genotyped in 45,290 cases and 41,880 controls of European ancestry from 41 studies in the Breast Cancer Association Consortium (BCAC). The SNPs were genotyped as part of a collaborative genotyping experiment involving four consortia (Collaborative Oncological Gene-environment Study, COGS) and used a custom Illumina iSelect genotyping array, iCOGS, comprising more than 200,000 SNPs. We identified SNPs at 41 new breast cancer susceptibility loci at genome-wide significance (P < 5 × 10−8). Further analyses suggest that more than 1,000 additional loci are involved in breast cancer susceptibility.
The domestication and development of cattle has considerably impacted human societies, but the histories of cattle breeds and populations have been poorly understood especially for African, Asian, and American breeds. Using genotypes from 43,043 autosomal single nucleotide polymorphism markers scored in 1,543 animals, we evaluate the population structure of 134 domesticated bovid breeds. Regardless of the analytical method or sample subset, the three major groups of Asian indicine, Eurasian taurine, and African taurine were consistently observed. Patterns of geographic dispersal resulting from co-migration with humans and exportation are recognizable in phylogenetic networks. All analytical methods reveal patterns of hybridization which occurred after divergence. Using 19 breeds, we map the cline of indicine introgression into Africa. We infer that African taurine possess a large portion of wild African auroch ancestry, causing their divergence from Eurasian taurine. We detect exportation patterns in Asia and identify a cline of Eurasian taurine/indicine hybridization in Asia. We also identify the influence of species other than Bos taurus taurus and B. t. indicus in the formation of Asian breeds. We detect the pronounced influence of Shorthorn cattle in the formation of European breeds. Iberian and Italian cattle possess introgression from African taurine. American Criollo cattle originate from Iberia, and not directly from Africa with African ancestry inherited via Iberian ancestors. Indicine introgression into American cattle occurred in the Americas, and not Europe. We argue that cattle migration, movement and trading followed by admixture have been important forces in shaping modern bovine genomic variation.
The DNA of domesticated plants and animals contains information about how species were domesticated, exported, and bred by early farmers. Modern breeds were developed by lengthy and complex processes; however, our use of 134 breeds and new analytical models enabled us to reveal some of the processes that created modern cattle diversity. In Asia, Africa, North and South America, humpless (Bos t. taurus or taurine) and humped (Bos t. indicus or indicine) cattle were crossbred to produce hybrids adapted to the environment and local production systems. The history of Asian cattle involves the domestication and admixture of several species whereas African taurines arose through the introduction of domesticated Fertile Crescent taurines and their hybridization with wild African aurochs. African taurine genetic background is commonly observed among European Mediterranean breeds. The absence of indicine introgression within most European taurine breeds, but presence within three Italian breeds is consistent with at least two separate migration waves of cattle to Europe, one from the Middle East which captured taurines in which indicine introgression had already occurred and the second from western Africa into Spain with no indicine introgression. This second group seems to have radiated from Spain into the Mediterranean resulting in a cline of African taurine introgression into European taurines.
Genetic and environmental influences on brain morphology were assessed in an extended-pedigree design by extracting depth-position profiles (DPP) of the central sulcus (CS). T1-weighted magnetic resonance images were used to measure CS length and depth in 467 human subjects from 35 extended families. Three primary forms of DPPs were observed. The most prevalent form, present in 70% of subjects, was bimodal, with peaks near hand and mouth regions. Trimodal and unimodal configurations accounted for 15 and 8%, respectively. Genetic control accounted for 56 and 66% of between-subject variance in average CS depth and length, respectively, and was not significantly influenced by environmental factors. Genetic control over CS depth ranged from 1 to 50% across the DPP. Areas of peak heritability occurred at locations corresponding to hand and mouth areas. Left and right analogous CS depth measurements were strongly pleiotropic. Shared genetic influence lessened as the distance between depth measurements was increased. We argue that DPPs are powerful phenotypes that should inform genetic influence of more complex brain regions and contribute to gene discovery efforts.
T-condylar fractures of the distal humerus are infrequent injuries in children. There are little data regarding outcomes in this age group. The adult literature demonstrates a high rate of postinjury stiffness. We describe a large series of T-condylar fractures in children and set out to identify factors that influence the postoperative range of motion (ROM) in children. Our hypothesis was that starting motion early (<3 weeks) would favorably influence the postoperative ROM.
Patients were identified based on the Current Procedural Terminology (CPT) code for ORIF of supracondylar distal humerus fractures with intracondylar extension (24546). Patient records and radiographs were reviewed to determine the demographics, fracture characteristics, surgical approach and fixation, and postoperative immobilization time. Our outcome measure was ROM in flexion/extension at 3 months, 6 months, 1 year, and final follow-up. Patients were analyzed by Morrey’s criteria of −30° extension and 130° flexion to assess for postoperative elbow stiffness.
Thirty-eight potential patients from 1992 to 2010 were identified with specific T-condylar patterns. Twelve patients were excluded due to insufficient follow-up or lack of final ROM data. Our cohort included 26 patients (average age 13.4 years). The average postoperative immobilization time was 3.4 weeks (range 0.9−12 weeks). At the final follow-up, patients had −12° average extension and 130° average flexion. Nine patients (35 %) were stiff and 17 patients (65 %) had functional motion postoperatively. At 3 and 6 months, starting motion early yielded better flexion and extension ROM. Late-motion patients obtained similar results at the 1-year follow-up. Open fractures, gender, and age were all not significantly associated with elbow stiffness in our series, given the limited numbers.
Early ROM was associated with an earlier gain of functional motion without clear adverse consequences. Despite similar findings at the final follow-up, practitioners should consider instituting early ROM protocols to decrease the duration of stiffness and potential disability for the child and the family.
T-condylar; T-condylar distal humerus fractures; Upper extremity fractures
To investigate association of scavenger receptor class B, member 1
(SCARB1) genetic variants with serum carotenoid levels
of lutein (L) and zeaxanthin (Z) and macular pigment optical density
A cross-sectional study of healthy adults aged 20-70.
302 participants recruited following local advertisement.
MPOD was measured by customized heterochromatic flicker photometry.
Fasting blood samples were taken for serum L and Z measurement by HPLC and
lipoprotein analysis by spectrophotometric assay. Forty-seven single
nucleotide polymorphisms (SNPs) across SCARB1 were
genotyped using Sequenom technology. Association analyses were performed
using PLINK to compare allele and haplotype means, with adjustment for
potential confounding and correction for multiple comparisons by permutation
testing. Replication analysis was performed in the TwinsUK and CAREDS
Main outcome measures
Odds ratios (ORs) for macular pigment optical density area, serum
lutein and zeaxanthin concentrations associated with genetic variations in
SCARB1 and interactions between SCARB1
Following multiple regression analysis with adjustment for age, body
mass index, sex, high-density lipoprotein cholesterol (HDLc), low-density
lipoprotein cholesterol (LDLc), triglycerides, smoking, dietary L and Z
levels, 5 SNPs were significantly associated with serum L concentration and
1 SNP with MPOD (P<0.01). Only the association between rs11057841 and
serum L withstood correction for multiple comparisons by permutation testing
(P<0.01) and replicated in the TwinsUK cohort (P=0.014). Independent
replication was also observed in the CAREDS cohort with rs10846744
(P=2×10−4), a SNP in high linkage
disequilibrium with rs11057841 (r2=0.93). No significant
interactions by sex were found. Haplotype analysis revealed no stronger
association than obtained with single SNP analyses.
Our study has identified association between rs11057841 and serum L
concentration (24% increase per T allele) in healthy subjects, independent
of potential confounding factors. Our data supports further evaluation of
the role for SCARB1 in the transport of macular pigment and
the possible modulation of AMD risk through combating the effects of
oxidative stress within the retina.
Age-related macular degeneration; association study; lutein; macular pigment; macular pigment optical density; SCARB1; zeaxanthin
We developed and validated a set of self-administered, multi-dimensional indicators of sexual health among Canadians aged 16–24 years.
This study used a mixed-method qualitative and quantitative approach to develop and validate indicators of sexual health. We used the four-stage Dillman method to identify, focus-test, pilot-test, and validate key metrics to measure sexual health. We collected quantitative data to validate the measures through a computer-assisted self-interviewing program among a purposive sample of 1,158 people aged 16–24 years recruited from four Canadian provinces.
The survey contained 75 items measuring five dimensions of sexual health: (1) physical, mental, emotional, and social well-being in relation to sexuality; (2) approach to sexuality; (3) sexual relationships; (4) sexual experiences; and (5) discrimination, coercion, and violence. Principal components analysis for composite measures found seven components with eigenvalues ≥1. The factor structure was stable across gender, age, size of area of residence, and language in which the survey was completed. Cronbach's alpha coefficients ranged from 0.79 to 0.90. Indicators of condom use at last vaginal sex, protection self-efficacy, sexually transmitted infection/HIV testing self-efficacy, and sexual orientation also showed good construct validity.
The indicators constituted a conceptually grounded survey that is easy for young adults to complete and contains valid, reliable, and psychometrically robust measures. The survey instrument provides a tool for future research to collect population-level data to measure and monitor trends in the sexual health of young people in Canada.
High-resolution peripheral quantitative computed tomography (HR-pQCT) has recently been introduced as a clinical research tool for in vivo assessment of bone quality. The utility of this technique to address important skeletal health questions requires translation to standardized multi-center data pools. Our goal was to evaluate the feasibility of pooling data in multi-center HR-pQCT imaging trials.
Reproducibility imaging experiments were performed using structure and composition-realistic phantoms constructed from cadaveric radii. Single-center precision was determined by repeat scanning over short (<72hrs), intermediate (3–5mo), and long-term intervals (28mo). Multi-center precision was determined by imaging the phantoms at nine different HR-pQCT centers. Least significant change (LSC) and root mean squared coefficient of variation (RMSCV) for each interval and across centers was calculated for bone density, geometry, microstructure, and biomechanical parameters.
Single-center short-term RMSCVs were <1% for all parameters except Ct.Th (1.1%), Ct.Th.SD (2.6%), Tb.Sp.SD (1.8%), and porosity measures (6–8%). Intermediate-term RMSCVs were generally not statistically different from short-term values. Long-term variability was significantly greater for all density measures (0.7–2.0%; p < 0.05 vs. short-term) and several structure measures: Ct.Th (3.4%; p < 0.01 vs. short-term), Ct.Po (15.4%; p < 0.01 vs. short-term), and Tb.Th (2.2%; p < 0.01 vs. short-term). Multi-center RMSCVs were also significantly higher than short-term values: 2–4% for density and µFE measures (p < 0.0001), 2.6–5.3% for morphometric measures (p < 0.001), while Ct.Po was 16.2% (p < 0.001).
In the absence of subject motion, multi-center precision errors for HR-pQCT parameters were generally less than 5%. Phantom-based multi-center precision was comparable to previously reported in vivo single-center precision errors, although this was approximately 2–5 times worse than ex vivo short-term precision. The data generated from this study will contribute to the future design and validation of standardized procedures that are broadly translatable to multi-center study designs.
HR-pQCT; osteoporosis; precision; bone; microstructure; bone strength; multi-center studies
The economic downturn of 2007 created significant fiscal losses for public and private agencies conducting behavioral prevention. Such macro-economic changes may influence program implementation and sustainability. We examined how public and private agencies conducting RESPECT, a brief HIV/STI (sexually transmitted infection) counseling and testing intervention, adapted to fiscal loss and how these adaptations impacted program fidelity. We collected qualitative and quantitative data in a national sample of 15 agencies experiencing fiscal loss. Using qualitative analyses, we examined how program fidelity varied with different types of adaptations. Agencies reported three levels of adaptation: agency-level, program-level, and direct fiscal remedies. Private agencies tended to use direct fiscal remedies, which were associated with higher fidelity. Some agency-level adaptations contributed to reductions in procedural fit, leading to negative staff morale and decreased confidence in program effectiveness, which in turn, contributed to poor fidelity. Findings describe a “work stress pathway” that links program fiscal losses to poor staff morale and low program fidelity.
Implementation; Fidelity; HIV/STI behavioral prevention; Economic downturn; Fiscal loss; Adaptions; Work strain
Malignant Peripheral Nerve Sheath Tumors (MPNSTs) are soft tissue sarcomas that arise in connective tissue surrounding peripheral nerves. They occur sporadically in a subset of patients with Neurofibromatosis type-1 (NF1). MPNSTs are highly aggressive, therapeutically resistant, and typically fatal. Using comparative transcriptome analysis, we identified CXCR4, a G protein-coupled receptor, as highly expressed in mouse models of NF1-deficient MPNSTs, but not in non-transformed precursor cells. The chemokine receptor CXCR4 and its ligand, CXCL12, promote MPNST growth by stimulating cyclin D1 expression and cell cycle progression through PI3-Kinase (PI3K) and β-catenin signaling. Suppression of CXCR4 activity, either by shRNA or pharmacological inhibition decreases MPNST cell growth in culture and inhibits tumorigenesis in allografts and in spontaneous genetic mouse models of MPNST. We further demonstrate conservation of these activated molecular pathways in human MPNSTs. Our findings indicate a role for CXCR4 in NF1-associated MPNST development, and identify a novel therapeutic target.
Microcos paniculata is a large shrub or small tree that grows in several countries in South and Southeast Asia. In the present study, three new piperidine alkaloids, microgrewiapines A-C (1-3), as well as three known compounds, inclusive of microcosamine A (4), 7′-(3′,4′-dihydroxyphenyl)-N-[4-methoxyphenyl)ethyl]propenamide (5), and liriodenine (6), were isolated from cytotoxic fractions of the separate chloroform-soluble extracts of the stem bark, branches, and leaves of M. paniculata. Compounds 1-6 and 1a showed a range of cytotoxicity values against the HT-29 human colon cancer cell line. When evaluated for their effects on human α3β4 or α4β2 nicotinic acetylcholine receptors (nAChRs), several of these compounds were shown to be active as nAChR antagonists. As a result of this study, microgrewiapine A (1) was found to be a selective cytotoxic agent for colon cancer cells over normal colon cells, and to exhibit nicotinic receptor antagonistic activity for both the hα3β4 and hα4β2 receptor subtypes.
Genome-wide association studies (GWASs) of renal cell cancer (RCC) have identified four susceptibility loci thus far. To identify an additional RCC common susceptibility locus, we conducted a GWAS and performed a meta-analysis with published GWASs (totalling 2215 cases and 8566 controls of European background) and followed up the most significant association signals [nine single nucleotide polymorphisms (SNPs) in eight genomic regions] in 3739 cases and 8786 controls. A combined analysis identified a novel susceptibility locus mapping to 2q22.3 marked by rs12105918 (P = 1.80 × 10−8; odds ratio 1.29, 95% CI: 1.18–1.41). The signal localizes to intron 2 of the ZEB2 gene (zinc finger E box-binding homeobox 2). Our findings suggest that genetic variation in ZEB2 influences the risk of RCC. This finding provides further insights into the genetic and biological basis of inherited genetic susceptibility to RCC.
We report a paracrine effect whereby endothelial cells (ECs) promote the cancer stem cell (CSC) phenotype of human colorectal cancer (CRC) cells. We showed that, without direct cell-cell contact, ECs secrete factors that promoted the CSC phenotype in CRC cells via Notch activation. In human CRC specimens, CD133 and Notch intracellular domain-positive cells co-localized with CRC cells in perivascular regions. An EC-derived, soluble form of Jagged-1, via ADAM17 proteolytic activity, led to Notch activation in CRC cells in a paracrine manner; these effects were blocked by immunodepletion of Jagged-1 in EC conditioned medium or blockade of ADAM17 activity. ECs play an active role in promoting Notch signaling and the CSC phenotype by secreting soluble Jagged-1.
Through the use of genetic, enzymatic, metabolomic, and structural analyses, we have discovered the catabolic pathway for proline betaine, an osmoprotectant, in Paracoccus denitrificans and Rhodobacter sphaeroides. Genetic and enzymatic analyses showed that several of the key enzymes of the hydroxyproline betaine degradation pathway also function in proline betaine degradation. Metabolomic analyses detected each of the metabolic intermediates of the pathway. The proline betaine catabolic pathway was repressed by osmotic stress and cold stress, and a regulatory transcription factor was identified. We also report crystal structure complexes of the P. denitrificans HpbD hydroxyproline betaine epimerase/proline betaine racemase with l-proline betaine and cis-hydroxyproline betaine.
At least half of the extant protein annotations are incorrect, and the errors propagate as the number of genome sequences increases exponentially. A large-scale, multidisciplinary sequence- and structure-based strategy for functional assignment of bacterial enzymes of unknown function has demonstrated the pathway for catabolism of the osmoprotectant proline betaine.
Although two related species may have extremely similar phenotypes, the genetic networks underpinning this conserved biology may have diverged substantially since they last shared a common ancestor. This is termed Developmental System Drift (DSD) and reflects the plasticity of genetic networks. One consequence of DSD is that some orthologous genes will have evolved different in vivo functions in two such phenotypically similar, related species and will therefore have different loss of function phenotypes. Here we report an RNAi screen in C. elegans and C. briggsae to identify such cases. We screened 1333 genes in both species and identified 91 orthologues that have different RNAi phenotypes. Intriguingly, we find that recently evolved genes of unknown function have the fastest evolving in vivo functions and, in several cases, we identify the molecular events driving these changes. We thus find that DSD has a major impact on the evolution of gene function and we anticipate that the C. briggsae RNAi library reported here will drive future studies on comparative functional genomics screens in these nematodes.
Although two related species may appear similar, the genetic pathways that underpin this shared biology may have drifted and changed. This phenomenon is known as Developmental System Drift (DSD). One consequence of DSD is that equivalent genes may play different roles in phenotypically similar, related species but there have been no systematic studies to examine this. How often do genes have different functions in similar species? Are certain genes more likely to change functions? Finally, what are the molecular changes that drive this? Here, we compare the effects of reducing the levels of over 1300 different genes in two species of nematode worm. These worms are very similar— they live in the same ecological niche, and have near-identical development and behavior. We find that over 25% of conserved genes have different functions in these two species, showing that DSD has a major impact on how gene function evolves. Intriguingly, we find that genes that have arisen recently are most likely to change functions and that this is often driven by changes in their expression. This is the first systematic comparison of loss of function phenotypes in related species and sheds light on how genetic pathways rewire during DSD.
To explore experiences and perceptions of frontline administrators involved in the systems-based management of laboratory test ordering and results handling in general medical practice.
Qualitative using focus group interviews.
West of Scotland general medical practices in three National Health Service (NHS) territorial board areas.
Convenience samples of administrators (receptionists, healthcare assistants and phlebotomists).
Transcript data were subjected to content analysis.
A total of 40 administrative staff were recruited. Four key themes emerged: (1) system variations and weaknesses (eg, lack of a tracking process is a known risk that needs to be addressed). (2) Doctor to administrator communication (eg, unclear information can lead to emotional impacts and additional workload). (3) Informing patients of test results (eg, levels of anxiety and uncertainty are experienced by administrators influenced by experience and test result outcome) and (4) patient follow-up and confidentiality (eg, maintaining confidentiality in a busy reception area can be challenging). The key findings were explained in terms of sociotechnical systems theory.
The study further confirms the safety-related problems associated with results handling systems and adds to our knowledge of the communication and psychosocial issues that can affect the health and well-being of staff and patients alike. However, opportunities exist for practices to identify barriers to safe care, and plan and implement system improvements to accommodate or mitigate the potential for human error in this complex area.
Genetic variants in nicotinic acetylcholine receptor and alcohol metabolism genes have been associated with propensity to smoke tobacco and drink alcohol, respectively, and also implicated in genetic susceptibility to head and neck cancer. In addition to smoking and alcohol, tobacco chewing is an important oral cancer risk factor in India. It is not known if these genetic variants influence propensity or oral cancer susceptibility in the context of this distinct etiology.
We examined 639 oral and pharyngeal cancer cases and 791 controls from two case-control studies conducted in India. We investigated six variants known to influence nicotine addiction or alcohol metabolism, including rs16969968 (CHRNA5), rs578776 (CHRNA3), rs1229984 (ADH1B), rs698 (ADH1C), rs1573496 (ADH7), and rs4767364 (ALDH2).
The CHRN variants were associated with the number of chewing events per day, including in those who chewed tobacco but never smoked (P = 0.003, P = 0.01 for rs16969968 and rs578776 respectively). Presence of the variant allele contributed to approximately 13% difference in chewing frequency compared to non-carriers. While no association was observed between rs16969968 and oral cancer risk (OR = 1.01, 95% CI = 0.83– 1.22), rs578776 was modestly associated with a 16% decreased risk of oral cancer (OR = 0.84, 95% CI = 0.72– 0.98). There was little evidence for association between polymorphisms in genes encoding alcohol metabolism and oral cancer in this population.
The association between rs16969968 and number of chewing events implies that the effect on smoking propensity conferred by this gene variant extends to the use of smokeless tobacco.