Differences in endplate deformation of the adjacent and augmented vertebra following cement augmentation

Vertebral cement augmentation can restore the stiffness and strength of a fractured vertebra and relieve chronic pain. Previous finite element analysis, biomechanical tests and clinical studies have indirectly associated new adjacent vertebral fractures following augmentation to altered loading. The aim of this repeated measures in situ biomechanical study was to determine the changes in the adjacent and augmented endplate deformation following cement augmentation of human cadaveric functional spine units (FSU) using micro-computed tomography (micro-CT). The surrounding soft tissue and posterior elements of 22 cadaveric human FSU were removed. FSU were assigned to two groups, control (n = 8) (loaded on day 1 and day 2) and augmented (n = 14) (loaded on day 1, augmented 20% cement fill, and loaded on day 2). The augmented group was further subdivided into a prophylactic augmentation group (n = 9), and vertebrae which spontaneously fractured during loading on day 1 (n = 5). The FSU were axially loaded (200, 1,000, 1,500-2,000 N) within a custom made radiolucent, saline filled loading device. At each loading step, FSUs were scanned using the micro-CT. Endplate heights were determined using custom software. No significant increase in endplate deformation following cement augmentation was noted for the adjacent endplate (P > 0.05). The deformation of the augmented endplate was significantly reduced following cement augmentation for both the prophylactic and fracture group (P < 0.05, P < 0.01, respectively). Endplate deformation of the controls showed no statistically significant differences between loading on day 1 and day 2. A linear relationship was noted between the applied compressive load and endplate deflection (R (2) = 0.58). Evidence of significant endplate deformation differences between unaugmented and augmented FSU, while evident for the augmented endplate, was not present for the adjacent endplate. This non-invasive micro-CT method may also be useful to investigate endplate failure, and parameters that predict vertebral failure.

Multimodal approach in the use of clinical scoring, morphological MRI and biochemical T2-mapping and diffusion-weighted imaging in their ability to assess differences between cartilage repair tissue after microfracture therapy and matrix-associated autologous chondrocyte transplantation: a pilot study

OBJECTIVE: The aim of the present pilot study is to show initial results of a multimodal approach using clinical scoring, morphological magnetic resonance imaging (MRI) and biochemical T2-relaxation and diffusion-weighted imaging (DWI) in their ability to assess differences between cartilage repair tissue after microfracture therapy (MFX) and matrix-associated autologous chondrocyte transplantation (MACT). METHOD: Twenty patients were cross-sectionally evaluated at different post-operative intervals from 12 to 63 months after MFX and 12-59 months after MACT. The two groups were matched by age (MFX: 36.0+/-10.4 years; MACT: 35.1+/-7.7 years) and post-operative interval (MFX: 32.6+/-16.7 months; MACT: 31.7+/-18.3 months). After clinical evaluation using the Lysholm score, 3T-MRI was performed obtaining the MR observation of cartilage repair tissue (MOCART) score as well as T2-mapping and DWI for multi-parametric MRI. Quantitative T2-relaxation was achieved using a multi-echo spin-echo sequence; semi-quantitative diffusion-quotient (signal intensity without diffusion-weighting divided by signal intensity with diffusion weighting) was prepared by a partially balanced, steady-state gradient-echo pulse sequence. RESULTS: No differences in Lysholm (P=0.420) or MOCART (P=0.209) score were observed between MFX and MACT. T2-mapping showed lower T2 values after MFX compared to MACT (P=0.039). DWI distinguished between healthy cartilage and cartilage repair tissue in both procedures (MFX: P=0.001; MACT: P=0.007). Correlations were found between the Lysholm and the MOCART score (Pearson: 0.484; P=0.031), between the Lysholm score and DWI (Pearson:-0.557; P=0.011) and a trend between the Lysholm score and T2 (Person: 0.304; P=0.193). CONCLUSION: Using T2-mapping and DWI, additional information could be gained compared to clinical scoring or morphological MRI. In combination clinical, MR-morphological and MR-biochemical parameters can be seen as a promising multimodal tool in the follow-up of cartilage repair.

Differences between dual X-ray absorptiometry using pencil beam and fan beam modes and their determinants in vivo and in vitro

The aim of this study was to determine the influence of individual factors on differences in bone mineral density (BMD) using dual X-ray absorptiometry pencil beam (PB) and fan beam (FB) modes in vivo and in vitro. PB.BMD and FB.BMD of 63 normal Caucasian females ages 21-80 yr were measured at the lumbar spine and hip. Residuals of the FB/PB regression were used to assess the impact of height, weight, adiposity index (AI) (= weight/height(3/2)), back tissue thickness, and PB.BMD, respectively, on FB/PB difference. The Hologic Anthropomorphic Spine Phantom (ASP) was measured using the PB and FB modes at two different levels to assess the impact of scanning mode and focus distance. The European Spine Phantom (ESP) prototype, a geometrically well-defined phantom with known vertebral densities, was measured using PB and FB modes and analyzed manually to determine the impact of bone density on FB/PB difference and automatically to determine the impact of edge detection on FB/PB difference. Population BMD results were perfectly correlated, but significantly overestimated by 1.5% at the lumbar spine and underestimated by 0.7% at the neck, 1.8% at the trochanter, and 2.0% at the total hip, respectively, when using the FB compared with PB mode. At the lumbar spine, the FB/PB residual correlated negatively with height (r = 0.34, p < 0.01) and PB.BMD (r = 0.48, p <: 0. 0001) and positively with AI (r = 0.26, p < 0.05). At the hip, residual of trochanter correlated positively with weight (r = 0.36, p < 0.01) and AI (r = 0.36, p < 0.01). The FB mode significantly increased ASP BMD by 0.7% compared with PB. Using the FB mode, increasing focus distance significantly (p < 0.001) decreased area and bone mineral content, but not BMD. By contrast, increasing focus distance significantly decreased PB.BMD by 0.7%. With the ESP, the PB mode supplied accurate projected are of the bone (AREA) results but significant underestimation of specified BMD in the manual analysis. The FB mode significantly underestimated PB. AREA by 2.9% but fitted specified BMD quite well. FB/PB overestimation was larger for the low-density (+8.7%) than for the high-density vertebra (+4. 9%). The automated analysis resulted in more than 14% underestimation of PB. AREA (low-density vertebra) and an almost 13% overestimation of PB.BMD (high-density vertebra) using FB. In conclusion, FB and PB measurements are highly correlated at the lumbar spine and hip with small but significant BMD differences related to height, adiposity, and BMD. In clinical practice, it can be erroneous to switch from one method to another, especially in women with low bone density.

Gender differences in methods of suicide attempts and prevalence of previous suicide attempts

Objective: Suicide attempts are important predictors of completed suicide. Adolescents admitted to the emergency room of a large university hospital in Bern after a suicide attempt during the years 2004-2010 were prospectively assessed for methods of suicide attempt. Method: Adolescents (N = 257; 66.5% female; age 14-21 years), presenting after a suicide attempt, were assessed with the WHO/EURO Multicentre Study on Parasuicide assessment tool. Results: Males more often used jumping from a high place (14% vs. 4.6% in females, p < .05) and less often intoxication (36% vs. 71.3%, p < .01). At least one previous suicide attempt was reported in 100 patients (44.4%; more females than males: Cramer-V = 0.21; p = .002). Of these, 35 adolescents did not present to this hospital or not at all for a previous suicide attempt. Conclusions: The present study is the first to examine methods of suicide attempts according to the ICD-10 X codes in this age group. Gender differences were observed. Because a relevant number of patients did not present to the same hospital or not at all for a previous suicide attempt, studies on pathways to care of adolescents after their first suicide attempt are important for early detection and intervention strategies.

Accounting for baseline differences and measurement error in the analysis of change over time

If change over time is compared in several groups, it is important to take into account baseline values so that the comparison is carried out under the same preconditions. As the observed baseline measurements are distorted by measurement error, it may not be sufficient to include them as covariate. By fitting a longitudinal mixed-effects model to all data including the baseline observations and subsequently calculating the expected change conditional on the underlying baseline value, a solution to this problem has been provided recently so that groups with the same baseline characteristics can be compared. In this article, we present an extended approach where a broader set of models can be used. Specifically, it is possible to include any desired set of interactions between the time variable and the other covariates, and also, time-dependent covariates can be included. Additionally, we extend the method to adjust for baseline measurement error of other time-varying covariates. We apply the methodology to data from the Swiss HIV Cohort Study to address the question if a joint infection with HIV-1 and hepatitis C virus leads to a slower increase of CD4 lymphocyte counts over time after the start of antiretroviral therapy.

0 and Metacognition: Relations and individual differences in 2nd graders

Introduction. Prospective Memory (PM), defined as the ability to remember to perform intended activities at some point in the future (Kliegel & Jäger, 2007), is crucial to succeed in everyday life. PM seems to increase over the childhood years (Zimmermann & Meier, 2006), but yet little is known about PM competences in children in general, but also about factors that influence its development. Currently, a number of studies has focused on factors that might influence PM performance, with EF being potentially influencing mechanisms (Ford, Driscoll, Shum & Macaulay, 2012; Mahy & Moses, 2011). Also metacognitive processes (MC: monitoring and control) are assumed to be involved while learning or optimizing one’s performance (Krebs & Roebers, 2010; 2012; Roebers, Schmid, & Roderer, 2009). Yet, the empirical relation between PM, EF and MC remains rather unclear. We intend to examine relations and explain individual differences in PM performance. Method. An empirical cross-sectional study on 120 2nd graders will be presented. Participants completed six EF tasks (a Stroop, two Updating Tasks, two Shifting Tasks, a Flanker Task), a computerised event-based PM Task and a MC spelling task. Children were tested individually in two sessions of 30 minutes each. Each of the three EF components defined by Miyake, Friedman, Emerson, Witzki & Howerter (2002) was represented by two variables. PM performance was represented by PM accuracy. Metacognitive processes (control, monitoring) were represented separately. Results. Preliminary analyses (SEM) indicate a substantial association between EF (updating, inhibition) and PM. Further, MC seems to be significantly related only to EF. We will explore whether metacognitive monitoring is related to PM monitoring (Roebers, 2002; Mantylä, 2007). As to EF and MC, we expect the two domains to be empirically well distinguishable and nevertheless substantially interrelated. Discussion. The results are discussed on a broader and interindividual level.

Sex identification and PIT-tagging: tools and prospects for studying intersexual differences in freshwater fishes

This study evaluated a technique to allow the long-term monitoring of individual fishes of known sex in the wild using sex confirmation in close proximity to the reproductive period combined with individual tagging. Hundreds of partially migratory roach Rutilus rutilus were tagged with passive integrated transponders (PIT) following sex determination in spring and various performance measures were compared with fish tagged outside the reproductive period in autumn. Short-term survival was > 95% for R. rutilus sexed and tagged under natural field conditions. Total length (LT) did not affect the probability of survival within the size range tagged (119–280mm), nor were there differences in timing of migration the following season between individuals sexed and tagged in spring and individuals tagged in autumn (i.e. outside the reproductive period). Also, a similar per cent of R. rutilus sexed and tagged in spring and tagged in autumn migrated the following season (34·5 and 34·7%). Moreover, long-term recapture data revealed no significant differences in body condition between R. rutilus individuals sexed and tagged in spring, individuals tagged in autumn and unmanipulated individuals. The observed sex ratio of recaptured fish did not differ from the expected values of equal recapture rates between males and females. Hence, there is no observable evidence for an adverse effect of tagging close to the reproductive period and therefore this method is suitable for studying intersexual differences and other phenotypic traits temporarily expressed during reproduction at the individual level in fishes.

Cohort and Gender Differences in Psychosocial Adjustment to Later-Life Widowhood

Objectives. Despite the large body of literature on bereavement, little is known about the impact of sociohistorical context on individual reactions to spousal loss. This study examines the effect of marital status, time period and gender on physical and mental health, and whether reported difficulties following spousal loss differ at 2 distinctive time periods. Method. Two cohorts of older bereaved persons (n = 753) in Switzerland, surveyed in 1979 and 2011, were compared regarding their reports of difficulties related to marital loss. The bereaved spouses were also compared with a group of married contemporaries (n = 1,517) regarding subjective health and depressive symptoms. Results. Marital status and gender each have independent effects on subjective health and depressive symptoms. The effects of widowhood on subjective health differed significantly at both time points. Widowed individuals in 2011, especially women, reported fewer social and financial difficulties than their counterparts in 1979. However, the effect of widowhood on depressive symptoms and psychological difficulties did not differ significantly across time points. Discussion. Social changes in the late 20th century may be protective for older adults’ physical, social, and financial well-being in the face of spousal loss, yet these changes do not alleviate widow(er)s’ psychological distress.

Sex differences in heart rate variability: a longitudinal study in international elite cross-country skiers

PURPOSE: Exercise-related sudden cardiac deaths (SCD) occur with a striking male predominance. A higher sympathetic tone in men has been suggested as risk factor for SCD. Elite athletes have the highest risk for exercise-related SCD. We aimed to analyze the autonomic nervous system of elite cross-country skiers from Norway, Russia and Switzerland in supine position and after orthostatic challenge in various training periods (TP). METHOD: Measurements of heart rate variability (HRV) were performed on a weekly basis over 1 year using an orthostatic challenge test with controlled breathing. Main outcome parameters were the high-frequency power in supine position (HFsupine) as marker of cardiac parasympathetic activity and the low-frequency/high-frequency power ratio after orthostatic challenge (LF/HFstand) as marker of cardiac sympathetic activation. Training intensity and duration were recorded daily and expressed as training strain. The training year was divided into three TPs. An average of weekly HRV measurements was calculated for each TP. RESULT: Female (n = 19, VO2max 62.0 +/- 4.6 ml kg(-1) min(-1), age 25.8 +/- 4.3 years) and male (n = 16, VO2max 74.3 +/- 6.3 ml kg(-1) min(-1), age 24.4 +/- 4.2 years) athletes were included. Training strain was comparable between sexes (all p > 0.05) and changed between TPs (all p < 0.05) while no HRV parameters changed over time. There were no sex differences in HFsupine while the LF/HFstand was significantly higher in male athletes in all TPs. CONCLUSION: For a comparable amount of training, male athletes showed constantly higher markers of sympathetic activity after a provocation maneuver. This may explain part of the male predominance in sports-related SCD.

MECHANISMS OF SPECIES DIFFERENCES IN BRAIN ACETYLCHOLINESTERASE SENSITIVITY TO ORGANOPHOSPHATE INHIBITION

In vitro incubation of acetylcholinesterase from brain tissue of several species with organophosphate compounds indicated that the concentrations required to inhibit 50% of acetylcholinesterase activity (IC(,50)) differed from species to species for the same compound (Murphy, et al., 1968; Andersen, et al., 1972, 1977 and 1978).^ The hypothesis that non-specific binding proteins (Lauwerys and Murphy, 1969a,b) exerts a protective effect on acetylcholinesterase, and thus cause the differences observed in IC(,50) studies was tested by a ('3)H-DFP binding experiment. It was found that differences in the amount of non-specific binding protein cannot explain the observed differences observed in IC(,50) studies.^ An alternative hypothesis, that acetylcholinesterase from different species have different affinities for binding and/or different rates of phosphorylation by organophosphate insecticides was tested by determining the apparent affinity constant (k(,a)) and apparent rate of phosphorylation (k(,p)). Kinetic studies indicated that acetylcholinesterases from different species have different sensitivities to inhibition by organophosphate insecticides, and the differences are due to different affinities for binding and/or different rates of phosphorylation by the same organophosphate compound.^ Studies of the spontaneous reactivation of acetylcholinesterase after inhibition by organophosphate insecticides also indicated that acetylcholinesterases from different species have different rates and extents of spontaneous reactivation. This further substantiates the hypothesis that acetylcholinesterases from different species have different kinetic characteristics with respect to organophosphate insecticides inhibition.^ Eleven paraoxon analogs were synthesized for a quantitative structure-activity relationship study. It was found that the electron-withdrawing power ((sigma)) and hydrophobicity ((PARAGR)) of the substituent are important in determining the anti-cholinesterase activity of paraoxon analogs. Thus, predictions of species differences in acetylcholinesterase sensitivities to paraoxon analogs can be made if the physicochemical parameters ((sigma) and (PARAGR)) of the substituents are known.^ In another approach, i.e. enzyme modeling, the sensitivity of rat brain acetylcholinesterase to organophosphate insecticides was used as the independent variable to predict the sensitivities of acetylcholinesterases from other species to the same compound. Regression equations were derived for each species based on nineteen organophosphate insecticides studied. It was found, that in addition to paraoxon analogs, this method is also applicable to other organophosphate compounds with wide variations in structure. Thus, the sensitivities of acetylcholinesterases from other species can also be predicted from the sensitivity of rat brain acetylcholinesterase. ^

Differences in health status of HIV infected children cared for by parents as compared to those cared for by grandparents

Purpose. The purpose of the study was to use measures of an HIV positive child's health to examine whether or not there is a difference in their health status according to caretaker and household economic status. ^ Study design. This was a case comparison study between HIV infected children living with parents and those living with grandparents. ^ Study setting. The study was conducted at the Pediatric Infectious Disease Clinic (PIDC) in Mulago, Kampala, Uganda. ^ Participants. 369 HIV-infected children aged seven months to 15 years attending the PIDC between June 13th and August 15th 2007 as well as their caretakers. ^ Method. Patients were recruited during their clinic visits after they had seen the health care providers and waited to receive their medication. Methods used included a survey of all the 369 caregiver participants and abstraction of data from the 369 patient charts. ^ Results. There was no significant association between staging and caretaker status (OR: 0.73 95%CI 0.44–1.21 p=0.09). Children taken care of by grandparents were more likely to have low height for age z-scores and higher weight for height z-scores (OR: 0.32, 95%CI: 0.14–0.74, p = 0.005). There was no difference is social support seeking behavior between parents and grandparents. ^ Conclusion. There was no statistically significant association observed between caretaker status and presenting in advanced stages. This implies that the stage at which HIV-infected children present for care is not determined by the type of caretaker. Caretakers for HIV-infected children need a lot of support beyond medical care. ^

An assessment of differences in pediatric dental services provided for a Medicaid population when compared to a federally subsidized (military) clinic

Reimbursement for dental services performed for children receiving Medicaid is reimbursed per service while dental treatment for military dependents provided at a military installation is neither directly reimbursable to those providing the care nor billed to those receiving the care. The purpose of this study was to compare pediatric dental services provided for a Medicaid population to a federally subsidized military facility to compare treatment choices and subsequent costs of care. It was hypothesized that differences in dental procedures for Medicaid and military dependent children would exist based upon treatment philosophy and payment method. A total of 240 records were reviewed for this study, consisting of 120 Medicaid patients at the University of Texas Health Science Center at San Antonio (UTHSCSA) and 120 military dependents at Wilford Hall Medical Center (WHMC), Lackland Air Force Base, San Antonio. Demographic data and treatment information were abstracted for children receiving dental treatment under general anesthesia between 2002 and 2006. Data was analyzed using the Wilcoxon rank sum test, Kruskal-Wallis test, and Fisher's exact test. The Medicaid recipients treated at UTHSCSA were younger than patients at WHMC (40.2 vs. 49.8 months, p<.001). The university also treated significantly more Hispanic children than WHMC (78.3% vs. 30.0%, p<.001). Children at UTHSCSA had a mean of 9.5 decayed teeth and were treated with 2.3 composite fillings, 0 amalgam fillings, 5.6 stainless steel crowns, 1.1 pulp therapies, 1.6 extractions, and 1.0 sealant. Children at WHMC had a mean of 8.7 decayed teeth and were treated with 1.4 composite fillings, 0.9 amalgam fillings, 5.6 stainless steel crowns, 1.7 pulp therapies, 0.9 extractions, and 2.1 sealants. The means of decayed teeth, total fillings, and stainless steel crowns were not statistically different. UTHSCSA provided more composite fillings (p<.001), fewer amalgam fillings (p<.001), fewer pulp therapies (p <.001), more extractions (p=.01), and fewer sealants (p<.001) when compared to WHMC. Age and gender did not effect decay rates, but those of Hispanic ethnicity did experience more decay than non-Hispanics (9.5 vs. 8.6, p=.02). Based upon Texas Medicaid reimbursement rates from 2006, the cost for dental treatment at both sites was approximately $650 per child. The results of this study do not support the hypothesis that Medicaid providers provide less conservative therapies, which would be more costly, care when compared to a military treatment center. ^

PCR-based subtractive hybridization and differences in gene content among strains of Helicobacter pylori

Genes that are characteristic of only certain strains of a bacterial species can be of great biologic interest. Here we describe a PCR-based subtractive hybridization method for efficiently detecting such DNAs and apply it to the gastric pathogen Helicobacter pylori. Eighteen DNAs specific to a monkey-colonizing strain (J166) were obtained by subtractive hybridization against an unrelated strain whose genome has been fully sequenced (26695). Seven J166-specific clones had no DNA sequence match to the 26695 genome, and 11 other clones were mixed, with adjacent patches that did and did not match any sequences in 26695. At the protein level, seven clones had homology to putative DNA restriction-modification enzymes, and two had homology to putative metabolic enzymes. Nine others had no database match with proteins of assigned function. PCR tests of 13 unrelated H. pylori strains by using primers specific for 12 subtracted clones and complementary Southern blot hybridizations indicated that these DNAs are highly polymorphic in the H. pylori population, with each strain yielding a different pattern of gene-specific PCR amplification. The search for polymorphic DNAs, as described here, should help identify previously unknown virulence genes in pathogens and provide new insights into microbial genetic diversity and evolution.

Differences between males and females in rates of serotonin synthesis in human brain

Rates of serotonin synthesis were measured in the human brain using positron emission tomography. The sensitivity of the method is indicated by the fact that measurements are possible even after a substantial lowering of synthesis induced by acute tryptophan depletion. Unlike serotonin levels in human brain, which vary greatly in different brain areas, rates of synthesis of the indolamine are rather uniform throughout the brain. The mean rate of synthesis in normal males was found to be 52% higher than in normal females; this marked difference may be a factor relevant to the lower incidence of major unipolar depression in males.

Psychosocial Distress Screening in a Community Cancer Center: An Examination of Gender Differences

Objective: The aim of this study was to gain a better understanding of the needs of male and female oncology patients within a community cancer setting to inform the provision of psychosocial services. Data obtained from 835 single-page measures of oncology patient distress were collected and analyzed to examine the relationship between gender and reported level of distress, the source of this distress, and requests for follow-up from psychosocial service providers.Method: Patients in medical and radiation oncology were given a distress screener tool that included a distress thermometer, a problem checklist, and a list of psychosocial service providers with whom the patient could request to speak.Results: Women reported higher levels of distress than men (p=.003). Women were also more likely than men to endorse practical problems as the cause of their distress (p=.003). A marginally significant relationship between gender and requesting the cancer resource navigator was also found (p=. 059)Conclusion: Gender is a salient factor in reported distress among cancer patients. Although no single variable can entirely explain an individual's response to cancer, male and female patients do appear to have distinctive, gender-specific needs. Psychosocial interventions that account for differences related to gender-role may be particularly beneficial. These results also illustrate the utility of consistent screening practices to better understand and meet the psychosocial needs of oncology