Leg dominancy in relation to fast isometric torque production and squat jump height

We hypothesized that maximal unilateral isometric knee extensor torque, the rate of torque development during maximally fast isometric contractions and unilateral squat jump performance would be better with the dominant than non-dominant leg. Limb dominancy was established using the step up, balance recovery, and ball kick test. On two days, eight men (21.5 ± 2.2 years, means ± SD) performed unilateral maximal isometric contractions with their knee extensors (120° knee angle) with superimposed electrical stimulation to determine maximal torque and voluntary activation for both limbs. In addition, maximally fast isometric contractions without countermovement and unilateral squat jumps (SJ) starting from 120° knee angles were performed. Torque time integral (contractile impulse) over the first 40 ms after torque onset (TTI40) and maximal rates of torque development (MRTD) during voluntary and maximal electrical nerve stimulation were used to quantify initial torque rise. Limb dominancy tests were very consistent, but none of the parameters was (or tended to be) significantly different between limbs, neither during maximal electrical stimulation nor during voluntary attempts. Between limbs there were significant relationships for voluntary TTI40 (r ² = 0.94) and maximal SJ height (r ² = 0.88) and both parameters were significantly related in both limbs (r ² = 0.69 and 0.75). In conclusion, unilateral fast torque generating capacity, muscle activation and squat jump performance were similar in both limbs, but differed substantially among subjects, with strong correlations between fast voluntary isometric torque development and jump height. These findings further challenge the concept of lower limb dominancy in dynamometry testing in sports and rehabilitation.     

Relative torque contribution of vastus medialis muscle at different knee angles

Aim: We investigated the relative contribution of the vastus medialis (VM) muscle to total isometric knee extension torque at 10°, 30°, 60° and 90° knee flexion. In the past a more prominent role of the VM muscle at more extended knee angles has been put forward. However, different components of the quadriceps muscle converge via a common distal tendon. We therefore hypothesized that the relative contribution of the VM to total knee extension torque would be similar across angles. Methods: At each knee angle the EMG isometric torque relations [20%, 25%, 30%, 35% maximal voluntary contraction (MVC)] of the rectus femoris (RF), vastus lateralis (VL) and VM muscle were established in 10 healthy male subjects; rectified surface EMG was normalized to M‐wave area. Subsequently, the VM was functionally eliminated by selective electrical surface stimulation with occluded blood flow. Results: There was no evidence for preferential activation of VM at any of the knee angles. Following VM elimination, total knee extension torque during maximal femoral nerve stimulation (three pulses at 300Hz) at 10°, 30°, 60° and 90°, respectively, decreased (P < 0.05) to (mean ± SD): 75.7 ± 12.2, 75.1 ± 9.3, 78.2 ± 7.2 and 76.0 ± 5.8% (P > 0.05 among knee angles). In addition, during voluntary contractions at 20% MVC the increases in torque output of RF and VL compensating for the loss of VM function were calculated from the increases in EMG and found to be similar (P > 0.05) at 10°, 30°, 60° and 90° values (%MVC), respectively, were: 9.1 ± 6.8, 7.5 ± 2.9, 5.9 ± 3.7 and 6.9 ± 3.4. Conclusion: The present findings support our hypothesis that the VM contributes similarly to total knee extension torque at different knee angles.     

Strength, size and activation of knee extensors followed during 8 weeks of horizontal bed rest and the influence of a countermeasure

Changes in the quadriceps femoris muscle with respect to anatomical cross sectional area (CSA), neural activation level and muscle strength were determined in 18 healthy men subjected to 8 weeks of horizontal bed rest (BR) with (n = 9) and without (n = 9) resistive vibration exercise (RVE). CSA of the knee extensor muscle group was measured with magnetic resonance imaging every 2 weeks during bed rest. In the control subjects (Ctrl), quadriceps femoris CSA decreased linearly over the 8 weeks of bed rest to −14.1 ± 5.2% (P < 0.05). This reduction was significantly (P < 0.001) mitigated by the exercise paradigm (−3.5 ± 4.2%; P < 0.05). Prior to and seven times during bed rest, maximal unilateral voluntary torque (MVT) values of the right leg were measured together with neural activation levels by means of a superimposed stimulation technique. For Ctrl, MVT decreased also linearly over time to −16.8 ± 7.4% after 8 weeks of bed rest (P < 0.01), whereas the exercise paradigm fully maintained MVT during bed rest. In contrast to previous reports, the maximal voluntary activation remained unaltered for both groups throughout the study. For Ctrl, the absence of deterioration of the activation level might have been related to the repeated testing of muscle function during the bed rest. This notion was supported by the observation that for a subset of Ctrl subjects (n = 5) the MVT of the left leg, which was not tested during BR, was reduced by 20.5 ± 10.1%, (P < 0.01) which was for those five subjects significantly (P < 0.05) more than the 11.1 ± 9.2% (P < 0.01) reduction for the right, regularly tested leg.Grants The BBR study was supported by grant 14431/02/NL/SH2 from the European Space Agency. The study was further sponsored by Charité—University Medicine Berlin (Campus Benjamin Franklin), DLR (German AeroSpace), MSD Sharp & Dohme, Lilly Germany, Servier Germany, Hoffmann-LaRoche, Siemens, Novartis, and Seca.     

Chemistry and the biological response against immunoisolating alginate-polycation capsules of different composition

Implantation of microencapsulated cells has been proposed as a therapy for a wide variety of diseases. An absolute requirement is that the applied microcapsules have an optimal biocompatibility. The alginate-poly-L-lysine system is the most commonly applied system but is still suffering from tissue responses provoked by the capsule materials. In the present study, we investigate the biocompatibility of microcapsules elaborated with two commonly applied alginates, i.e. an intermediate-G alginate and a high-G alginate. These alginates were coated with poly-L-lysine (PLL), poly-D-lysine (PDL) and poly-L-ornithine (PLO). The main objective of this study is to determine the interaction of each alginate matrix with the different polycations and the potential impact of these interactions in the modulation of the host's immune response. To address these issues the different types of microcapsules were implanted into the peritoneal cavity of rats for I month. After this period the microcapsules were recovered and they were evaluated by different techniques. Monochromatised X-ray photoelectron spectroscopy (XPS) was performance and the degree of capsular recovery, overgrowth on each capsule, and the cellular composition of the overgrowth were evaluated by histology. Our results illustrate that the different observed immune responses are the consequence of the variations in the interactions between the polycations and alginates rather than to the alginates themselves.Our results suggest that PLL is the best option available and that we should avoid using PLO and PDL in its present form since it is our goals to produce capsules that lack overgrowth and do not induce an immunological response as such.     

Evaluation of relapse after orthodontic therapy combined with orthognathic surgery in the treatment of skeletal class III

Introduction

Multidisciplinary treatment of skeletal malocclusion by orthognathic surgery in addition to orthodontics is a routine strategy believed to offer good functional and esthetic outcomes. Postoperative relapse is, however, a problem. The present study was conducted to analyze the stability of outcomes achieved by surgical treatment of skeletal class III patients in terms of the rate and extent of relapses.

Patients and methods

A total of 30 patients who had undergone orthodontic treatment combined with orthognathic surgery were included. The primary inclusion criterion was a skeletal class III treated by mandibular setback (Obwegeser/Dal Pont) surgery alone or combined with maxillary advancement (Le Fort I) surgery. Analysis was based on one preoperative and two postoperative cephalograms per patient.

Results

We observed relapse (defined, in accordance with Proffit, as changes >2 mm or 2°) at a rate of 24% after bimaxillary procedures, compared to a lower rate of 21% after mandibular setback procedures only. The relapse rate was 21% among patients who had undergone upper-jaw surgery versus 27% among those who had undergone lower-jaw surgery, which was statistically significant.

Conclusion

The majority of patients exhibited stable treatment outcomes. Maxillary advancement procedures were found to be less susceptible to relapse—resulting in more stable outcomes—and mandibular setback distances correlated positively with the degree of the relapse. No statistically significant differences were observed between the procedures conducted in both jaws versus in the lower jaw only, or in the extent of upper-jaw repositioning.     

Direct molecular diagnosis of myotonic dystrophy

Hecht BK, Donnelly A, Gedeon AK, Byard RW, Haan EA, Mulley JC. Direct molecular diagnosis of myotonic dystrophy. Clin Genet 1993: 43: 276–285. © Munksgaard, 1993 Myotonic dystrophy (DM) arises from an unstable trinucleotide (CTG_n) repeat sequence within the DM locus at 19q13.3. Twenty-three myotonic dystrophy families containing 205 persons with no symptoms, minimal manifestations, classic DM or congenital DM were investigated to validate the application of the pM10M6 probe to direct molecular diagnosis. Affected family members had been diagnosed clinically and the unaffected family members had been assigned carrier probabilities close to either zero or 100%, using closely linked flanking markers. Southern analysis identified all 89 DM gene carriers as having expansions of the unstable element. PstI detected all small expansions of the repeat sequence as easily seen discrete bands; but large expansions were usually seen as diffuse smears, sometimes difficult to distinguish from lane background. EcoRI concentrated these diffuse smears, associated with somatic instability, into discrete bands which were easy to detect; but it did not resolve the smaller expansions present in 9 (10%) of the DM carriers. It is essential that PstI and EcoRI gels are run in parallel to detect all DM gene carriers. The extent of expansion of CTG correlated with age of onset and disease severity. Biopsies of various fetal tissues from two terminated pregnancies confirmed the diagnosis obtained by CVS and revealed no heterogeneity between tissues at this developmental stage. Further expansion occurred during the culture of CVS cells, indicating that direct prenatal diagnosis needs to be carried out on CVS tissue rather than on cultured cells. The intergenerational change of the repeat sequence from DM parent to DM offspring showed a significant parental sex difference for those parents with large expansions. Contraction of the unstable element was observed in the three males carrying the largest expansions and could explain why congenital DM is exclusively of maternal origin.     

Early childhood internalizing problems,externalizing problems and their co-occurrence and (mal)adaptive functioning in emerging adulthood: a 16-year follow-up study

Purpose

A vast amount of studies suggest that internalizing or externalizing problems are related to individual functioning, and often co-occur. Yet, a focus on their additive and interactive effects is scarce. Furthermore, most research has focused on a limited number of developmental domains and mostly on maladaptive functioning. Therefore, the current prospective study examined whether early childhood (ages 4–8) internalizing and externalizing problems and their interaction were related to a broad range of (mal)adaptive functioning outcomes in emerging adulthood (ages 20–24).

Methods

Data from the Flemish Study on Parenting, Personality and Development were used. At Time 1 (1999) mothers of 374 children (45% boys) and fathers of 357 children (46% boys) rated internalizing and externalizing problems through the Child Behavior Checklist. Outcomes in emerging adulthood were measured through self-reports 16 years later across the following domains: psychological functioning, social functioning, work, physical health, and self-concept.

Results

Early externalizing problems were related to maladaptive outcomes on the psychological and social domains. With regard to adaptive functioning, externalizing problems were associated with lower satisfaction regarding general health on the physical domain. Early internalizing problems were not associated with any emerging adulthood outcomes. The interaction of (father reported) internalizing and externalizing problems was related to aggressive behavior.

Conclusion

Early childhood externalizing problems were associated with maladaptive and adaptive functioning over a time span of 16 years. The results add to studies on the implementation of prevention and intervention programs in early childhood and to the value for developing personalized interventions.

     

Drug monitoring of lamotrigine and oxcarbazepine combination during pregnancy

Little is known about pregnancy-induced alterations in the pharmacokinetics of the newer antiepileptic drugs, especially when used in combinations. Two women receiving combination therapy of lamotrigine (LTG) and oxcarbazepine (OXC) were followed prospectively during pregnancy and puerperium. Steady-state concentrations of LTG and the active metabolite of OXC, 10-hydroxycarbazepine (MHD), were measured at regular intervals using a dried blood spot method, and clearances were calculated. A strong effect of pregnancy on the clearance of both LTG and MHD was seen. An increase in seizure frequency occurred in both women. This stresses the importance of therapeutic drug monitoring of LTG and MHD during pregnancy. In case of breakthrough seizures or increased seizure frequency, dosage adjustment of both drugs may be required.     

Insight in psychosis: relationship with neurocognition, social cognition and clinical symptoms depends on phase of illness

Reduced insight has been reported in a majority of patients with a psychotic disorder. Most studies have focused on associations with neurocognition, neglecting relations with social cognition. Two hundred seventy patients with nonaffective psychosis participated in this study, which was part of the GROUP (Genetic Risk and OUtcome of Psychosis)-project. Linear regression analyses were performed to investigate the predictive value of composite measures of neurocognition, social cognition, and clinical symptoms. The moderating effect of phase of illness was also investigated. Insight was measured with a composite measure, based on the insight item on the Positive And Negative Syndrome Scale (PANSS) and the Birchwood Insight Scale (BIS). Insight on the BIS and the PANSS correlated significantly (r = .406). All independent variables correlated with the insight composite measure. The additional effect of social cognition and clinical symptoms were both significant. Phase of illness was a moderating variable: In patients with recent-onset psychosis (ROP), none of the independent variables explained variance. In patients with multiple episode or chronic psychosis, both social cognition and clinical symptoms had additional effects and explained insight, along with neurocognition, together explaining 20% of the variance. These findings indicate that multiple factors are associated with insight in psychosis. Specifically, associations of insight with social cognitive and clinical symptom measures were observed, over and above a contribution of neurocognition. This supports theories that imply a role for deficient emotion recognition and mentalizing in reduced insight. Further studies need to investigate insight in ROP into more detail.     

Moving beyond transition outcomes: Meta-analysis of remission rates in individuals at high clinical risk for psychosis

Recent evidence suggests that transition risks from initial clinical high risk (CHR) status to psychosis are decreasing. The role played by remission in this context is mostly unknown. The present study addresses this issue by means of a meta-analysis including eight relevant studies published up to January 2012 that reported remission rates from an initial CHR status. The primary effect size measure was the longitudinal proportion of remissions compared to non-remission in subjects with a baseline CHR state. Random effect models were employed to address the high heterogeneity across studies included. To assess the robustness of the results, we performed sensitivity analyses by sequentially removing each study and rerunning the analysis. Of 773 subjects who met initial CHR criteria, 73% did not convert to psychosis along a 2-year follow. Of these, about 46% fully remitted from the baseline attenuated psychotic symptoms, as evaluated on the psychometric measures usually employed by prodromal services. The corresponding clinical remission was estimated as high as 35% of the baseline CHR sample. The CHR state is associated with a significant proportion of remitting subjects that can be accounted by the effective treatments received, a lead time bias, a dilution effect, a comorbid effect of other psychiatric diagnoses.