To assess progesterone treatment of intractable seizures in women with partial epilepsy.
This randomized, double-blind, placebo-controlled, phase III, multicenter, clinical trial compared the efficacy and safety of adjunctive cyclic natural progesterone therapy vs placebo treatment of intractable seizures in 294 subjects randomized 2:1 to progesterone or placebo, stratified by catamenial and noncatamenial status. It compared treatments on proportions of ≥50% responders and changes in seizure frequency from 3 baseline to 3 treated menstrual cycles.
There was no significant difference in proportions of responders between progesterone and placebo in the catamenial and noncatamenial strata. Prespecified secondary analysis showed that the level of perimenstrual seizure exacerbation (C1 level) was a significant predictor of responders for progesterone but not placebo. With increasing C1 levels, responders increased from 21% to 57% with progesterone vs 19% to 20% with placebo. Reductions in seizure frequency correlated with increasing C1 levels for progesterone but not placebo, progressing from 26% to 71% for progesterone vs 25% to 26% for placebo. A prespecified clinically important separation between progesterone and placebo responders (37.8% vs 11.1%; p = 0.037) was realized among 21.4% of women who had C1 level ≥3.
There was no difference in the primary outcome of ≥50% responder rates between progesterone vs placebo for catamenial or noncatamenial groups. Post hoc findings suggest that the level of perimenstrual seizure exacerbation is a significant predictor of responder rate with progesterone and that progesterone may provide clinically important benefit for a subset of women with perimenstrually exacerbated seizures.
Classification of evidence:
This study provides Class III evidence that cyclic progesterone is ineffective in women with intractable partial epilepsy. Post hoc analysis identified a subset of women with higher levels of perimenstrual seizure exacerbation that were responsive to treatment.
Objective: To assess the clinical outcomes of triamcinolone acetonide spray for steroid-responsive dermatoses using investigator and patient global assessment scores and evaluate patient satisfaction. Design: This open-label, single-center, noncomparator study enrolled 42 patients (aged 18 years or older) with dermatoses. Patients were instructed to use triamcinolone acetonide spray 1 to 4 times daily, depending on investigator instructions, for up to 28 days. Measurements: Investigators and patients scored the overall severity of dermatoses based on a global assessment scale. Investigators also rated signs and symptoms of dermatoses and evaluated clinical outcomes based on an improvement assessment scale. Patient satisfaction with treatment was assessed at the end of treatment or at Day 28 using a questionnaire. Patients were evaluated on Days 7, 14, 21, and 28. Complete clearing of dermatoses warranted early discontinuation from the study. Results: Triamcinolone acetonide spray effectively improved dermatoses scores, clinical outcomes, and signs and symptoms of dermatoses. More than 80 percent of patients entered the study with moderate or severe dermatoses. Within 14 days, none had severe dermatoses, and by 28 days, 64 percent of patients were completely clear or almost clear. From the patient perspective, 51.3 percent experienced improvement in only three days, and 84.6 percent experienced improvement in seven days. An overwhelming number of patients (95%) preferred triamcinolone acetonide spray over creams and ointments, and more than half experienced a cooling effect upon contact with the spray. Conclusion: Triamcinolone acetonide spray is an effective topical corticosteroid that should be considered for patients with steroid-responsive dermatoses of all ranges of severity.
An intravesical instillation of 100 ml 1 or 2 mmol/l capsaicin has been used to treat detrusor hyperreflexia giving rise to intractable urinary incontinence in 12 patients with spinal cord disease and two other patients with detrusor overactivity of non-spinal origin. Nine patients, all of whom had spinal cord disease, showed some improvement in bladder function. The benefit was only shortlived and partial in four, but the remaining five achieved complete continence while performing intermittent self catheterisation. Urodynamic studies in these nine patients showed an increase in mean (SD) bladder capacity from 106 (57) to 302 (212) ml and a fall in the maximum detrusor pressure from 54 (20) to 36 (10) cm of water. There were no short term ill effects from the instillation and the improvement in bladder function lasted for between three weeks to six months, when in some patients it was repeated. The improvement in bladder behaviour shown in this study can be interpreted as showing that capsaicin sensitive afferents play an important part in the pathogenesis of detrusor hyperreflexia in spinal humans. Intravesical capsaicin seems a promising means of treating intractable detrusor hyperreflexia and studies with this substance may shed new light on other disorders of detrusor activity that cause incontinence.
We explore the influence of genetic variation on subjective well-being by employing a twin design and genetic association study. In a nationally-representative twin sample, we first show that about 33% of the variation in life satisfaction is explained by genetic variation. Although previous studies have shown that baseline happiness is significantly heritable, little research has considered molecular genetic associations with subjective well-being. We study the relationship between a functional polymorphism on the serotonin transporter gene (5-HTTLPR) and life satisfaction. We initially find that individuals with the longer, transcriptionally more efficient variant of this genotype report greater life satisfaction (n=2,545, p=0.012). However, our replication attempts on independent samples produce mixed results indicating that more work needs to be done to better understand the relationship between this genotype and subjective well-being. This work has implications for how economists think about the determinants of utility, and the extent to which exogenous shocks might affect individual well-being.
life satisfaction; twin study; genetic association; serotonin transporter gene; 5-HTTLPR; rs2020933
Concomitant mesh repair of large umbilical hernias and abdominoplasty pose a serious risk of devascularizing the umbilical stalk. A technique of placing mesh in a sublay manner, deep to the fascial defect, for an umbilical herniorrhaphy to avoid damage to the deep umbilical perforators during an abdominoplasty is described.
Abdominoplasty; Retrorectus; Umbilical hernia
Polychlorinated biphenyls (PCBs) are developmental neurotoxicants that produce cognitive and behavioral changes in children exposed during gestation and lactation. Coplanar PCBs bind the aryl hydrocarbon receptor (AHR) and can be sequestered in liver by cytochrome P450 1A2 (CYP1A2). The AHR is a ligand-activated transcription factor which increases expression of the CYP1 family, including CYP1A2. Our previous work examining genetic susceptibility to developmental PCB neurotoxicity showed that AhrbCyp1a2(−/−) mice with the high-affinity Ahrb allele and lacking CYP1A2 were most susceptible while AhrbCyp1a2(+/+) and poor-affinity AhrdCyp1a2(+/+) mice were resistant. To follow up, a fourth line of mice was generated with the AhrdCyp1a2(−/−) genotype and compared with the background strain AhrbCyp1a2(+/+). Dams received a PCB mixture or the corn oil vehicle at gestational day 10 (GD10) and postnatal day 5 (PND5). Offspring were tested at PND60 in open field locomotor, acoustic startle with pre-pulse inhibition (PPI), novel object recognition and Morris water maze. Locomotor activity was increased in PCB-treated AhrbCyp1a2(+/+) mice, but no differences were seen in control v. PCB-treated AhrdCyp1a2(−/−) mice. PCB-treated AhrdCyp1a2(−/−) mice had a higher baseline startle response and significantly reduced pre-pulse inhibition at the 74dB level compared with corn oil-treated controls (P<0.05). PCB-treated AhrdCyp1a2(−/−) mice had impairments in novel objective recognition (P<0.05) and during all three hidden platform phases of Morris water maze (P<0.01). Combined with our previous findings, these results indicate Cyp1a2 genotype is more important in susceptibility to PCB-induced deficits in learning and memory, but Ahr genotype appears more important when assessing acoustic startle-PPI and locomotor activity.
polychlorinated biphenyls; PCBs; CYP1A2; aryl hydrocarbon receptor; developmental neurotoxicity
Major postoperative infections (MPIs) are poorly understood complications of cardiac surgery. We examined the epidemiology, microbiology, and outcome of MPIs occurring after cardiac surgery.
The study cohort was drawn from the Society of Thoracic Surgeon National Cardiac Database and comprised adults who underwent cardiac surgery at 5 tertiary hospitals between 2000 and 2004. We studied the incidence, microbiology, and risk factors of MPI (bloodstream or chest wound infections within 30 days after surgery), as well as 30-day mortality. We used multivariate regression analyses to evaluate the risk of MPI and mortality.
MPI was identified in 341 of 10,522 patients (3.2%). Staphylococci were found in 52.5% of these patients, gram-negative bacilli (GNB) in 24.3%, and other pathogens in 23.2%. High body mass index, previous coronary bypass surgery, emergency surgery, renal impairment, immunosuppression, cardiac failure, and peripheral/cerebrovascular disease were associated with the development of MPI. Median postoperative duration of hospitalization (15 days vs 6 days) and mortality (8.5% vs 2.2%) were higher in patients with MPIs. Compared with uninfected individuals, odds of mortality were higher in patients with S aureus MPIs (adjusted odds ratio, 3.7) and GNB MPIs (adjusted odds ratio, 3.0).
Staphylococci accounted for the majority of MPIs after cardiac surgery. Mortality was higher in patients with Staphylococcus aureus- and GNB-related MPIs than in patients with MPIs caused by other pathogens and uninfected patients. Preventive strategies should target likely pathogens and high-risk patients undergoing cardiac surgery.
Wound infection; Sepsis; Cardiac surgical procedures; Morbidity; Mortality
Pursuit and saccades almost always select the same target. Is this the results of a common selection process or does smooth pursuit obligatorily follow the stimulus targeted by saccades? To address this question, we used microstimulation of the primate superior colliculus (SC) to redirect the eyes from a selected pursuit target to a distracter moving in the opposite direction. During each trial, monkeys pursued a horizontally moving array of colored target stimuli. In half of the trials, this target array was accompanied by a distracter array moving horizontally in the opposite direction, offset by the vertical amplitude of the stimulation-evoked saccade. We stimulated the SC during maintained pursuit on half of the trials, and measured pursuit eye velocity during the 50-ms interval immediately following the stimulation-evoked saccade to the distracter array. Saccades evoked by SC stimulation did not alter pursuit target selection. Pursuit velocity on average changed by less than 10% of that expected if the monkey had completely switched targets. Moreover, the same changes in velocity occurred when there was no distracter, indicating that even these small changes in pursuit velocity were a direct effect of the evoked saccade, not partial selection of the distracter. These results show that motor execution of saccades is not sufficient to select a pursuit target, and support the idea that the coordination of pursuit and saccades is accomplished by a shared target selection process.
target selection; attention; saccade; smooth pursuit; superior colliculus; eye movement
To assess the use and utility of the Freedom of Information Act (2000) in healthcare research since 2005 and to determine if any particular feature of studies found led to greater data acquisition.
PRISMA compliant systematic review.
An extensive literature search was performed of EMBASE, MEDLINE, CINAHL, psychINFO, BNI, AMED, HMIC and Health business elite databases from January 2005 to January 2013 using terms ‘Freedom of information’, ‘Freedom of information act’ and ‘Freedom of information act 2000’. Papers were considered for publication if they described utilising the UK Freedom of information act to gather data for healthcare research. 16 articles met these criteria.
Primary and Secondary outcome measures
Primary outcome was the number and characteristics of studies utilising the Freedom of Information Act to collect the data for healthcare research. Secondary outcome measures were any features that improved data acquisition rates (including to whom the request was made, the number of questions asked per request, etc.)
16 articles described utilising the Freedom of Information Act for healthcare research, and these investigated a broad range of topics. The median number of requests made was 86 (range 1–172), the total number of requests was 1732. A total of 15 817 pieces of data were retrieved by all studies. The amount of data collected was defined as the number of questions asked multiplied by the number of full responses. A median of five questions were asked per study (range 5–6.5) and the overall response rate was 86%. The National Health Service litigation authority responded to 100% of requests, while Primary Care Trusts had the lowest response rate of 81% for healthcare bodies. A positive correlation between number of requests made and data obtained (0.508, p<0.05) and number of requests made and increased response rate (0.737, p<0.01), both reached the statistical significance.
Researchers should make greater use of the Act to access the information they need that is not otherwise disclosed. We discuss the issues with the research utilising the Act and how future research of this type could be optimised.
HEALTH SERVICES ADMINISTRATION & MANAGEMENT; STATISTICS & RESEARCH METHODS
Human behaviour is thought to spread through face-to-face social networks, but it is difficult to identify social influence effects in observational studies9–13, and it is unknown whether online social networks operate in the same way14–19. Here we report results from a randomized controlled trial of political mobilization messages delivered to 61 million Facebook users during the 2010 US congressional elections. The results show that the messages directly influenced political self-expression, information seeking and real-world voting behaviour of millions of people. Furthermore, the messages not only influenced the users who received them but also the users’ friends, and friends of friends. The effect of social transmission on real-world voting was greater than the direct effect of the messages themselves, and nearly all the transmission occurred between ‘close friends’ who were more likely to have a face-to-face relationship. These results suggest that strong ties are instrumental for spreading both online and real-world behaviour in human social networks.
We hypothesize that the correlation between the radiation dose expressed as the biologically effective dose (BED) and the clinical endpoints will correlate better as the value of the α/β ratio is increased to >10 Gy, which theoretically minimizes the overestimation of the dose potency associated with the linear quadratic (LQ) formula in the setting of stereotactic body radiation therapy (SBRT) for early stage non-small cell lung cancer (NSCLC). A search was conducted in the PubMed electronic databases in August 2011. In the studies analyzed, increasing the α/β ratio is associated with an increase in the strength of the correlation between isocenter BED and local control, especially in the studies with median followup of ≥24 months, for which Spearman's correlation coefficients of 0.74–0.76 were achieved for α/β of 20 Gy, 30 Gy, and 50 Gy (P = 0.007–0.008). A trend toward statistical significance was observed for the correlation of isocenter BED and the 2-year overall survival when an α/β of 20 Gy was used approached statistical significance (P = 0.073). Our results suggest that an α/β > 10 Gy may be more appropriate for the prediction of dose response in the setting of lung SBRT.
The etiology of depression has long been thought to include social environmental factors. To quantitatively explore the novel possibility of person-to-person spread and network-level determination of depressive symptoms, analyses were performed on a densely interconnected social network of 12 067 people assessed repeatedly over 32 years as part of the Framingham Heart Study. Longitudinal statistical models were used to examine whether depressive symptoms in one person were associated with similar scores in friends, co-workers, siblings, spouses and neighbors. Depressive symptoms were assessed using CES-D scores that were available for subjects in three waves measured between 1983 and 2001. Results showed both low and high CES-D scores (and classification as being depressed) in a given period were strongly correlated with such scores in one's friends and neighbors. This association extended up to three degrees of separation (to one's friends’ friends’ friends). Female friends appear to be especially influential in the spread of depression from one person to another. The results are robust to multiple network simulation and estimation methods, suggesting that network phenomena appear relevant to the epidemiology of depression and would benefit from further study.
depression; social networks; sociology; social norms; mood
Baseline and nicotine-modulated behaviors were assessed in mice harboring a null mutant allele of the nicotinic acetylcholine receptor (nAChR) subunit gene α2 (Chrna2). Homozygous Chrna2−/− mice are viable, show expected sex and Mendelian genotype ratios, and exhibit no gross neuroanatomical abnormalities. A broad range of behavioral tests designed to assess genotype-dependent effects on anxiety (elevated plus maze and light/dark box), motor coordination (narrow bean traverse and gait), and locomotor activity revealed no significant differences between mutant mice and age-matched wild-type littermates. Furthermore, a panel of tests measuring traits, such as body position, spontaneous activity, respiration, tremors, body tone, and startle response, revealed normal responses for Chrna2-null mutant mice. However, Chrna2−/− mice do exhibit a mild motor or coordination phenotype (a decreased latency to fall during the accelerating rotarod test) and possess an increased sensitivity to nicotine-induced analgesia in the hotplate assay. Relative to wild-type, Chrna2−/− mice show potentiated nicotine self-administration and withdrawal behaviors and exhibit a sex-dependent enhancement of nicotine-facilitated cued, but not trace or contextual, fear conditioning. Overall, our results suggest that loss of the mouse nAChR α2 subunit has very limited effects on baseline behavior but does lead to the potentiation of several nicotine-modulated behaviors.
Here, we review the research we have conducted on social contagion. We describe the methods we have employed (and the assumptions they have entailed) to examine several datasets with complementary strengths and weaknesses, including the Framingham Heart Study, the National Longitudinal Study of Adolescent Health, and other observational and experimental datasets that we and others have collected. We describe the regularities that led us to propose that human social networks may exhibit a ‘three degrees of influence’ property, and we review statistical approaches we have used to characterize interpersonal influence with respect to phenomena as diverse as obesity, smoking, cooperation, and happiness. We do not claim that this work is the final word, but we do believe that it provides some novel, informative, and stimulating evidence regarding social contagion in longitudinally followed networks. Along with other scholars, we are working to develop new methods for identifying causal effects using social network data, and we believe that this area is ripe for statistical development as current methods have known and often unavoidable limitations.
social networks; contagion; human behavior; homophily; causal interence
Breast density is a significant breast cancer risk factor measured from mammograms. The most appropriate method for measuring breast density for risk applications is still under investigation. Calibration standardizes mammograms to account for acquisition technique differences prior to making breast density measurements. We evaluated whether a calibration methodology developed for an indirect x-ray conversion full field digital mammography (FFDM) technology applies to direct x-ray conversion FFDM systems.
Breast tissue equivalent (BTE) phantom images were used to establish calibration datasets for three similar direct x-ray conversion FFDM systems. The calibration dataset for each unit is a function of the target/filter combination, x-ray tube voltage, current × time (mAs), phantom height, and two detector fields of view (FOVs). Methods were investigated to reduce the amount of calibration data by restricting the height, mAs, and FOV sampling. Calibration accuracy was evaluated with mixture phantoms. We also compared both intra- and inter-system calibration characteristics and accuracy.
Calibration methods developed previously apply to direct x-ray conversion systems with modification. Calibration accuracy was largely within the acceptable range of ± 4 standardized units from the ideal value over the entire acquisition parameter space for the direct conversion units. Acceptable calibration accuracy was maintained with a cubic-spline height interpolation, representing a modification to previous work. Calibration data is unit specific, can be acquired with the large FOV, and requires a minimum of one reference mAs sample. The mAs sampling, calibration accuracy, and the necessity for machine specific calibration data are common characteristics and in agreement with our previous work.
The generality of our calibration approach was established under ideal conditions. Evaluation with patient data using breast cancer status as the endpoint is required to demonstrate that the approach produces a breast density measure associated with breast cancer.
Breast density; Calibration; Phantom imaging; Direct x-ray conversion; Full field digital mammography
The adverse impact of obesity on health outcomes may be lower in older adults and African Americans than the general US population.
To examine and compare the relationship between obesity and all-cause mortality and functional decline among older US adults.
Longitudinal cohort study.
Secondary analysis of data from the 1994-2000 Medicare Current Beneficiary Survey linked to Medicare Enrollment files through 4/22/2008.
20,975 community-dwelling participants of the 1994-2000 Medicare Current Beneficiary Survey who were aged 65 and older.
All-cause mortality through 4/22/2008; new/worsening disability in performing activities of daily living (ADL) and instrumental activities of daily living (IADL) within 2 years.
Of the study sample, 37% were overweight (BMI 25-30 kg/m2), and 18% were obese (BMI>30 kg/m2); 48% died during the 14 years of follow-up; 27% had ADL and 43% had IADL disability at baseline. Of those without severe disability at baseline, 17% developed new/worsening ADL disability within 2 years; 26% developed new/worsening IADL disability. After adjustment, adults with a BMI>35 kg/m2 were the only group above the normal BMI range that were at higher risk of mortality [Hazard Ratio in men, 1.49 (1.20, 1.85) and in women, 1.21 (1.06, 1.39)] when compared to the reference group (BMI=22.0-24.9 kg/m2), p=0.003 for BMI-sex interaction. In contrast, both overweight and obesity were associated with new or progressive ADL and IADL disability in a dose-dependent fashion, particularly for White men and women. We detected significant interactions between BMI and sex, but not between BMI and race for any outcome although risk estimates for ADL disability appeared generally attenuated in African Americans relative to Whites.
Observational study; baseline data are self-reported; limited power to detect differences between Whites and African Americans.
Among older US adults, obesity was not associated with mortality except for those with at least moderately severe obesity. However, lower levels of obesity were associated with the development of new or worsening disability within two years. Efforts to prevent disability in older adults should target those who are overweight or obese.
To determine the safety of sentinel lymph node biopsy as a replacement for inguinal femoral lymphadenectomy in selected women with vulvar cancer.
Patients and Methods
Eligible women had squamous cell carcinoma, at least 1-mm invasion, and tumor size ≥ 2 cm and ≤ 6 cm. The primary tumor was limited to the vulva, and there were no groin lymph nodes that were clinically suggestive of cancer. All women underwent intraoperative lymphatic mapping, sentinel lymph node biopsy, and inguinal femoral lymphadenectomy. Histologic ultra staging of the sentinel lymph node was prescribed.
In all, 452 women underwent the planned procedures, and 418 had at least one sentinel lymph node identified. There were 132 node-positive women, including 11 (8.3%) with false-negative nodes. Twenty-three percent of the true-positive patients were detected by immunohistochemical analysis of the sentinel lymph node. The sensitivity was 91.7% (90% lower confidence bound, 86.7%) and the false-negative predictive value (1-negative predictive value) was 3.7% (90% upper confidence bound, 6.1%). In women with tumor less than 4 cm, the false-negative predictive value was 2.0% (90% upper confidence bound, 4.5%).
Sentinel lymph node biopsy is a reasonable alternative to inguinal femoral lymphadenectomy in selected women with squamous cell carcinoma of the vulva.
It has been consistently demonstrated that delusions are related to jumping to conclusions (JTC), a data-gathering bias and potential candidate endophenotype of psychosis. Recent research suggests that JTC may be a marker of treatment response. However, we know little about the factors contributing to the occurrence of this reasoning bias. This study investigated the relationship between JTC and hypothesised deficits in working memory, employing standard well-validated neuropsychological tests, in people with current delusions.
One hundred and twenty six people with schizophrenia spectrum psychosis and current delusions were assessed for current symptoms, and tested for JTC. We compared performance on tests of working memory in those with the reasoning bias and those without.
As expected, 30–40% of this sample of people with current delusions showed the JTC bias. There were no differences in premorbid IQ between those with and without the JTC reasoning bias. However, the performance of the JTC group was significantly worse on tests of working memory.
The JTC data-gathering bias is associated with impairments in working memory. New non-pharmacological interventions for people with delusions, designed to improve data gathering, may benefit from incorporating strategies to overcome deficits in working memory.
Delusions; Jumping to conclusions; Working memory; Schizophrenia-spectrum psychosis
Wounding due to mechanical injury or insect feeding causes a wide array of damage to plant cells including cell disruption, desiccation, metabolite oxidation, and disruption of primary metabolism. In response, plants regulate a variety of genes and metabolic pathways to cope with injury. Tomato (Solanum lycopersicum) is a model for wound signaling but few studies have examined the comprehensive gene expression profiles in response to injury. A cross-species microarray approach using the TIGR potato 10-K cDNA array was analyzed for large-scale temporal (early and late) and spatial (locally and systemically) responses to mechanical wounding in tomato leaves. These analyses demonstrated that tomato regulates many primary and secondary metabolic pathways and this regulation is dependent on both timing and location. To determine if LAP-A, a known modulator of wound signaling, influences gene expression beyond the core of late wound-response genes, changes in RNAs from healthy and wounded Leucine aminopeptidase A-silenced (LapA-SI) and wild-type (WT) leaves were examined. While most of the changes in gene expression after wounding in LapA-SI leaves were similar to WT, overall responses were delayed in the LapA-SI leaves. Moreover, two pathogenesis-related 1 (PR-1c and PR-1a2) and two dehydrin (TAS14 and Dhn3) genes were negatively regulated by LAP-A. Collectively, this study has shown that tomato wound responses are complex and that LAP-A’s role in modulation of wound responses extends beyond the well described late-wound gene core.
Alzheimer's disease (AD) is the leading cause of dementia and represents a significant burden on the global economy and society. The role of transition metals, in particular copper (Cu), in AD has become of significant interest due to the dyshomeostasis of these essential elements, which can impart profound effects on cell viability and neuronal function. We tested the hypothesis that there is a systemic perturbation in Cu compartmentalization in AD, within the brain as well as in the periphery, specifically within erythrocytes. Our results showed that the previously reported decrease in Cu within the human frontal cortex was confined to the soluble (P < 0.05) and total homogenate (P < 0.05) fractions. No differences were observed in Cu concentration in erythrocytes. Our data indicate that there is a brain specific alteration in Cu levels in AD localized to the soluble extracted material, which is not reflected in erythrocytes. Further studies using metalloproteomics approaches will be able to elucidate the metabolic mechanism(s) that results in the decreased brain Cu levels during the progression of AD.
In humans, congenital myopathy-linked tropomyosin mutations lead to skeletal muscle dysfunction, but the cellular and molecular mechanisms underlying such dysfunction remain obscure. Recent studies have suggested a unifying mechanism by which tropomyosin mutations partially inhibit thin filament activation and prevent proper formation and cycling of myosin cross-bridges, inducing force deficits at the fiber and whole-muscle levels. Here, we aimed to verify this mechanism using single membrane-permeabilized fibers from patients with three tropomyosin mutations (TPM2-null, TPM3-R167H and TPM2-E181K) and measuring a broad range of parameters. Interestingly, we identified two divergent, mutation-specific pathophysiological mechanisms. (i) The TPM2-null and TPM3-R167H mutations both decreased cooperative thin filament activation in combination with reductions in the myosin cross-bridge number and force production. The TPM3-R167H mutation also induced a concomitant reduction in thin filament length. (ii) In contrast, the TPM2-E181K mutation increased thin filament activation, cross-bridge binding and force generation. In the former mechanism, modulating thin filament activation by administering troponin activators (CK-1909178 and EMD 57033) to single membrane-permeabilized fibers carrying tropomyosin mutations rescued the thin filament activation defect associated with the pathophysiology. Therefore, administration of troponin activators may constitute a promising therapeutic approach in the future.
Although existing guidelines support the utilization of intracranial pressure (ICP) monitoring in patients with traumatic brain injury (TBI), the evidence suggesting benefit is limited. To evaluate the impact on outcome, we determined the relationship between ICP monitoring and mortality in centers participating in the American College of Surgeons Trauma Quality Improvement Program (TQIP). Data on 10,628 adults with severe TBI were derived from 155 TQIP centers over 2009–2011. Random-intercept multilevel modeling was used to evaluate the association between ICP monitoring and mortality after adjusting for important confounders. We evaluated this relationship at the patient level and at the institutional level. Overall mortality (n=3769) was 35%. Only 1874 (17.6%) patients underwent ICP monitoring, with a mortality of 32%. The adjusted odds ratio (OR) for mortality was 0.44 [95% confidence interval (CI), 0.31–0.63], when comparing patients with ICP monitoring to those without. It is plausible that patients receiving ICP monitoring were selected because of an anticipated favorable outcome. To overcome this limitation, we stratified hospitals into quartiles based on ICP monitoring utilization. Hospitals with higher rates of ICP monitoring use were associated with lower mortality: The adjusted OR of death was 0.52 (95% CI, 0.35–0.78) in the quartile of hospitals with highest use, compared to the lowest. ICP monitoring utilization rates explained only 9.9% of variation in mortality across centers. Results were comparable irrespective of the method of case-mix adjustment. In this observational study, ICP monitoring utilization was associated with lower mortality. However, variability in ICP monitoring rates contributed only modestly to variability in institutional mortality rates. Identifying other institutional practices that impact on mortality is an important area for future research.
head injury; intracranial pressure; multilevel analysis; traumatic brain injury
In the recent years, the Internet has been used as a medium to find sexual partners and engage in risky sexual behavior. This has changed the way in which men having have sex with men (MSM) seek sexual partners and has increased the number of high-risk sexual encounters. Therefore, developers of human immunodeficiency virus (HIV)-prevention interventions have also started using the Internet as a viable medium to promote safe sexual behaviors. However, much of the efforts thus far have been aimed at HIV-negative rather than HIV-positive MSM. HIV-positive individuals continue to engage in risky sexual behaviors and thus constitute an important group in which HIV prevention strategies need to be addressed. Therefore, HIV prevention in HIV-positive MSM is a critical issue.
Condom-Him, an Internet-based intervention tailored to increase condom use among HIV-positive MSM, was developed with the aim of improving condom use, self-efficacy, and intentions to use condoms among these individuals. The acceptability and feasibility of this Internet-based intervention will be examined in a pilot study.
We will perform a randomized controlled parallel-group superiority trial. HIV-positive MSM who currently engage in unprotected anal sex will be recruited for the study. Participants will be randomly assigned using a one-to-one allocation ratio generated by the computer program. The researchers will be blinded to participant’s group assignment. Participants will be assigned either to use the Condom-Him intervention (experimental arm) or to view a list of websites containing HIV/AIDS related information (control arm). Self-administered questionnaires will be provided online before randomization (baseline) and two weeks after intervention (post-test).
The study will include a total of 60 participants with 30 in each group. The results from this pilot study will provide further evidence for a larger study to examine the effectiveness of this intervention and will provide a cost-effective and widely accessible approach to HIV prevention for HIV-positive MSM.
Internet-based interventions for HIV-positive MSM, a population that has been under-represented in the efforts for positive prevention of HIV within Canada, have the potential to provide a cost-effective strategy, which influences the way in which information is accessed and provided to high-risk individuals. The advantages of an Internet-based intervention include the potential to provide consistency in the delivery of an intervention and the ability to disseminate the intervention to a wider population. Internet-based interventions are perceived as vital tools in combating HIV infection within the realm of social media. Therefore, it is important to determine the feasibility and acceptability of these interventions before implementing them.
Clinicaltrials.gov: NCT01726153; http://clinicaltrials.gov/ct2/show/NCT01726153 (Archived by WebCite at http://www.webcitation.org/6Jljzip8B).
HIV-positive; men having sex with men; condom use; self-efficacy; intention; HIV prevention; pilot study; intervention