Blood transcriptomics to facilitate diagnosis and stratification in pediatric rheumatic diseases - a proof of concept study

BACKGROUND

Transcriptome profiling of blood cells is an efficient tool to study the gene expression signatures of rheumatic diseases. This study aims to improve the early diagnosis of pediatric rheumatic diseases by investigating patients' blood gene expression and applying machine learning on the transcriptome data to develop predictive models.

METHODS

RNA sequencing was performed on whole blood collected from children with rheumatic diseases. Random Forest classification models were developed based on the transcriptome data of 48 rheumatic patients, 46 children with viral infection, and 35 controls to classify different disease groups. The performance of these classifiers was evaluated by leave-one-out cross-validation. Analyses of differentially expressed genes (DEG), gene ontology (GO), and interferon-stimulated gene (ISG) score were also conducted.

RESULTS

Our first classifier could differentiate pediatric rheumatic patients from controls and infection cases with high area-under-the-curve (AUC) values (AUC = 0.8 ± 0.1 and 0.7 ± 0.1, respectively). Three other classifiers could distinguish chronic recurrent multifocal osteomyelitis (CRMO), juvenile idiopathic arthritis (JIA), and interferonopathies (IFN) from control and infection cases with AUC ≥ 0.8. DEG and GO analyses reveal that the pathophysiology of CRMO, IFN, and JIA involves innate immune responses including myeloid leukocyte and granulocyte activation, neutrophil activation and degranulation. IFN is specifically mediated by antibacterial and antifungal defense responses, CRMO by cellular response to cytokine, and JIA by cellular response to chemical stimulus. IFN patients particularly had the highest mean ISG score among all disease groups.

CONCLUSION

Our data show that blood transcriptomics combined with machine learning is a promising diagnostic tool for pediatric rheumatic diseases and may assist physicians in making data-driven and patient-specific decisions in clinical practice.

A Severe Form of Familial Desminopathy Due to a Homozygous Nonsense DES Variant in Two Siblings

Familial primary desminopathies are usually autosomal dominantly inherited and present at the age of 20 to 40 years with progressive muscle weakness and atrophy, cardiomyopathy, and cardiac arrhythmias. Cardiac features may precede the muscular weakness. Here, we report the rare case of two siblings presenting with a desminopathy at pediatric age, due to homozygous nonsense variations (c.700G > T [p.Glu234Ter]) in DES, representing an autosomal recessive inheritance pattern. The homozygous state of these variants is expected to result in the complete absence of desmin production. Rare autosomal recessive DES variants are associated with an earlier clinical presentation (from childhood to early adulthood) and faster evolution compared with more common autosomal dominant variants. A normal resting electrocardiography (ECG) and cardiac ultrasound can be a pitfall, as seen in our patient who has extensive fibrotic scarring on cardiac magnetic resonance imaging (MRI). We recommend yearly cardiac ultrasound, yearly 24-hour Holter monitoring and 2 yearly cardiac MRI from the age of 10 years in all asymptomatic patients. Heterozygous patients usually have no or only mild complaints but, though not yet reported in autosomal recessive desminopathies, muscular complaints are possible, as seen in the father of our patients. The prognosis for these patients with desminopathy presenting in childhood is unpredictable but anticipated as poor.

The role of Effortful Control in Substance Use Disorders

Background and aim: Temperament and personality traits are important factors underlying the vulnerability for both initiation and continuation of addictive behaviors. In SUDs there is a high comorbidity with mood and anxiety disorders and personality disorders. As there is a growing interest in the possible transdiagnostic role of Effortful Control in both SUDs as in their comorbid disorders the current study therefore investigates the influence of reactive (Behavioral Inhibition System and Behavioral Activation System, BIS/BAS) and regulative (Effortful Control, EC) temperament and their interaction in relation to clinical symptomatology and PDs in adult inpatients with SUD. Methods: The EC, BIS/BAS, SCL-90-R and ADP-IV questionnaires were administered to 841 patients (age between 17 y and 71 y) with a SUD admitted at the treatment unit for addiction of a psychiatric hospital. Results: Hierarchical regression analyses showed that both, clinical symptomatology and PDs were related to low levels of effortful control (EC). Furthermore, cluster C PDs were related to high levels of BIS and low levels of EC; whereas cluster B PDs were related to low levels of EC and high levels of BAS for the narcissistic and histrionic PD. An interaction effect (BIS*EC) was found for the Schizotypal PD, all other interactions (BIS*EC and BAS*EC) were not significant. Discussion: We found that low EC is involved in all clinical symptomatology and PDs in a sample of inpatients with SUDs. Therapeutic interventions aiming at strengthening effortful control can possibly result in better treatment outcomes for both the addiction as the comorbid psychopathology

The drive for thinness: Towards a mechanistic understanding of avoidance behaviors in a non-clinical population

Fear of weight gain is a cardinal feature of eating disorders, including Anorexia Nervosa (AN). This fear motivates behaviors aimed at avoiding weight gain, such as restricting food intake. Of note, avoidance in AN is not confined to food-related items but extends to intense emotional states. Despite the presence of several forms of excessive avoidance in AN, little is known about the mechanisms underpinning avoidance behavior in AN. In the present exploratory study, we investigated whether university students with an elevated desire to avoid weight gain (as measured through self-reported Drive for Thinness, DT) show deficits in generic avoidance learning. Two-hundred and seventy-five female students filled in the Eating Disorder Inventory-II (EDI-II) and performed a food-unrelated avoidance task. Generalized and linear mixed models (GLMM) revealed that students scoring higher on the DT scale of the EDI-II showed more ineffective avoidance, suggesting a tendency for excessive avoidance in at-risk individuals for AN. Similar results might extend to other eating disorders.

Obstetrical outcome after B-Lynch sutures and ligation of uterine arteries: A case report

Objective

To illustrate the obstetrical outcome after B-Lynch sutures and ligation of the uterine arteries.

Case

A 26-year-old nulliparous woman. A caesarean section performed for obstructed labour was complicated by uterine atony. A B-Lynch uterine compression suture technique was used combined with ligation of the ascending branches of the uterine arteries. Before the subsequent fertility treatment, gel instillation sonography and power Doppler imaging showed a normal uterine cavity and restored myometrial vascularization. Subsequent caesarean section showed external adhesions on the anterior uterine serosa. A healthy baby of normal weight was delivered. There was focal placenta accreta; the underlying myometrium was strikingly thinner and prone to inversion.

Discussion

After B-Lynch sutures and ligation of the ascending branches of the uterine arteries, the pregnancy was subsequently uncomplicated. The potential association between B-Lynch sutures and placenta accreta or uterine inversion in a subsequent pregnancy has to be assessed in further studies. This case report illustrates how 3D gel instillation sonography is a valuable tool to evaluate the integrity of the uterine cavity.

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3D gel instillation sonography gives the best evaluation of the uterus after B-Lynch sutures have been used.

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Normal fertility and pregnancy are possible after B-Lynch sutures have been used.

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Normal fertility and pregnancy are possible after ligation of the uterine arteries.

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B-Lynch sutures and ligation of the uterine arteries are useful in postpartum haemorrhage.

Predicting the incidence of non-suicidal self-injury in college students

Background:

Despite increased awareness that non-suicidal self-injury (NSSI) poses a significant public health concern on college campuses worldwide, few studies have prospectively investigated the incidence of NSSI in college and considered targeting college entrants at high risk for onset of NSSI.

Methods:

Using data from the Leuven College Surveys (n = 4,565; 56.8%female, Mage = 18.3, SD = 1.1), students provided data on NSSI, sociodemographics, traumatic experiences, stressful events, perceived social support, and mental disorders. A total of 2,163 baseline responders provided data at a two-year annual follow-up assessment (63.2% conditional response rate).

Results:

One-year incidence of first onset NSSI was 10.3% in year 1 and 6.0% in year 2, with a total of 8.6% reporting sporadic NSSI (1–4 times per year) and 7.0% reporting repetitive NSSI (≥ 5 times per year) during the first two years of college. Many hypothesized proximal and distal risk factors were associated with the subsequent onset of NSSI (ORs = 1.5–18.2). Dating violence prior to age 17 and severe role impairment in daily life were the strongest predictors. Multivariate prediction suggests that an intervention focused on the 10% at highest risk would reach 23.9% of students who report sporadic, and 36.1% of students who report repetitive NSSI during college (cross-validated AUCs =.70–.75).

Discussion:

The college period carries high risk for the onset of NSSI. Individualized web-based screening may be a promising approach for detecting young adults at high risk for self-injury and offering timely intervention.

Challenges in diagnosing ectopic thymus tissue in children

The presentation of a fast-growing cervical mass necessitates prompt attention due to risk of the mass effect on vital structures and requires preferential screening for infections, bleeding and malignancies in an extensive list of differential diagnoses. This case report describes a 4.5-year-old boy with a fast-growing, unilateral lesion in the neck, with clinical features in keeping with malignant characteristics. Surgical excision with pathocytological examination revealed an exceptional diagnosis of haemorrhage in an ectopic cervical thymic cyst. Thymic cysts are a rare cause of unilateral masses in the neck, usually presenting as an asymptomatic, painless, slow-growing or stable mass anywhere along the thymopharyngeal duct. Spontaneous haemorrhages in thymic tissue can occur, often due to coagulation defects. Treatment of symptomatic thymic cysts is based on surgical excision. Partial resection of the thymus should be encouraged if possible, since clinical consequences of removing all thymic tissue in children are still unclear.

The associations between non-suicidal self-injury and first onset suicidal thoughts and behaviors

BACKGROUND

Theoretical and empirical literature suggests that non-suicidal self-injury (NSSI) is an important correlate of suicide risk. The present study was designed to evaluate: (a) whether NSSI is associated with increased odds of subsequent onsets of suicidal thoughts and behaviors (STB) independent of common mental disorders, (b) whether NSSI is associated with increased risk of transitioning from suicide ideation to attempt, and (c) which NSSI characteristics are associated with STB after NSSI.

METHOD

Using discrete-time survival models, based on retrospective age of onset reports from college students (n = 6,393, 56.8% female), we examined associations of temporally prior NSSI with subsequent STB (i.e., suicide ideation, plan, and attempt) controlling mental disorders (i.e., MDD, Broad Mania, GAD, Panic Disorder, and risk for Alcohol Dependence). NSSI characteristics associated with subsequent STB were examined using logistic regressions.

RESULTS

NSSI was associated with increased odds of subsequent suicide ideation (OR = 2.8), plan (OR = 3.0), and attempt (OR = 5.5) in models that controlled for the distribution of mental disorders. Further analyses revealed that NSSI was associated with increased risk of transitioning to a plan among those with ideation, as well as attempt among those with a plan (ORs = 1.7-2.1). Several NSSI characteristics (e.g., automatic positive reinforcement, earlier onset NSSI) were associated with increased odds of experiencing STB.

LIMITATIONS

Surveys relied on self-report, and thus, there is the potential for recall bias.

CONCLUSIONS

This study provides support for the conceptualization of NSSI as a risk factor for STB. Investigation of the underlying pathways accounting for these time-ordered associations is an important avenue for future research.

Using Indirect Measurement Tasks to Assess the Self–Concept of Personality: A Systematic Review and Meta–Analyses

This systematic review presents the current state of research investigating the implicit self–concept of personality. First, we present results on meta–analyses estimating internal consistency, reliability coefficients, the implicit–explicit consistency and the single association predictive effect of implicit self–concept of personality measures. To do this, studies were aggregated over personality domains. Second, for each of the Five Factor personality domains, different aspects of construct validity and predictive validity are reviewed in a narrative way. Results show that implicit self–concept of personality measures are reliable, and there is evidence for the construct and predictive validity of these implicit measures, especially in the extraversion and agreeableness domains of personality. However, it must be kept in mind that clear evidence for publication bias was found for studies examining the single association predictive pattern. Finally, this systematic review identifies some achievable improvements that are needed in future research. Large cross–lab efforts are important in this respect. Moreover, the implicit self–concept of personality field must move from an ‘ad hoc’ to a ‘validation’ approach in developing new indirect measurement tasks. By adopting these research objectives, the information processing account of personality will increase its potential to become integrated into mainstream personality theory and research. Copyright © 2017 European Association of Personality Psychology

[Reliability of OTC advertisement Relevance and quality of cited literature]

Introduction Pharmacist receive a lot of publicity for OTC products. Often one or more literature references are mentioned to support the advertising claims. Objective In this study we examine: [1) whether the advertising claim is consistent with what is stated in the literature references mentioned on the leaflet and [2] whether these literature references are trustworthy. Method Through 60 randomly selected community pharmacies, pharmacist-directed advertisements for OTC products I= medicines, medical devices, dietary supplements and parapharmacy) with at least one bibliographic reference, were collected. The literature references listed in these leaflets were assessed in terms of content [= is the claim consistent with the information in the reference) and technically [= evaluation of the quality of the references]. Results The 85 collected OTC advertisements made 214 claims that referred to 243 references. Of these, 128 references did not support the promotional claim. The remaining 84 references did support the corresponding claim. From 31 references no full text was obtained. Of the 84 supporting references 44 were of dubious quality. The remaining 40 references were found to be reliable. Conclusion This study shows that the literature references in advertising leaflets for OTC-products are not a reliable source of information on the advertised product. Pharmacists should deal critically with this information and should be encouraged to consult reliable scientific sources.

Non-Suicidal Self-Injury Among Dutch and Belgian Adolescents: Personality, Stress and Coping

Background

This study examines: (1) the prevalence of Non-Suicidal Self-Injury (NSSI) among Dutch and Belgian adolescents, (2) the associations between Big Five personality traits and NSSI engagement/versatility (i.e., number of NSSI methods), and (3) whether these associations are mediated by perceived stress and coping.

Methods

A total of 946 Flemish (46%) and Dutch (54%) non-institutionalized adolescents (Mean age = 15.52; SD = 1.34, 44% females) were surveyed. Measures included the NSSI subscale of the Self-Harm-Inventory, the Dutch Quick Big Five Personality questionnaire, the Perceived Stress Scale and the Utrecht Coping List for Adolescents. Examination of zero-order correlations was used to reveal associations, and hierarchical regression analysis was used to reveal potential mediators which were further examined within parallel mediation models by using a bootstrapping-corrected procedure.

Results

Lifetime prevalence of NSSI was 24.31%. Neuroticism; perceived stress; and distractive, avoidant, depressive, and emotional coping were positively associated with NSSI engagement, whereas Agreeableness, Conscientiousness; and active, social, and optimistic coping were negatively associated with NSSI engagement. Observed relationships between personality traits and NSSI engagement were consistently explained by perceived stress and depressive coping. A higher versatility of NSSI was not associated with any Big Five personality trait, but was associated with higher scores on perceived stress and depressive coping and with lower scores on active and optimistic coping.

Conclusion

Our study suggests that a specific personality constellation is associated with NSSI engagement via high stress levels and a typical depressive reaction pattern to handle stressful life events.

Systematic review and meta-analysis of prevalence studies in transsexualism

BACKGROUND

Over the last 50 years, several studies have provided estimates of the prevalence of transsexualism. The variation in reported prevalence is considerable and may be explained by factors such as the methodology and diagnostic classification used and the year and country in which the studies took place. Taking these into consideration, this study aimed to critically and systematically review the available literature measuring the prevalence of transsexualism as well as performing a meta-analysis using the available data.

METHODS

Databases were systematically searched and 1473 possible studies were identified. After initial scrutiny of the article titles and removal of those not relevant, 250 studies were selected for further appraisal. Of these, 211 were excluded after reading the abstracts and a further 18 after reading the full article. This resulted in 21 studies on which to perform a systematic review, with only 12 having sufficient data for meta-analysis. The primary data of the epidemiological studies were extracted as raw numbers. An aggregate effect size, weighted by sample size, was computed to provide an overall effect size across the studies. Risk ratios and 95% confidence intervals (CIs) were calculated. The relative weighted contribution of each study was also assessed.

RESULTS

The overall meta-analytical prevalence for transsexualism was 4.6 in 100,000 individuals; 6.8 for trans women and 2.6 for trans men. Time analysis found an increase in reported prevalence over the last 50 years.

CONCLUSIONS

The overall prevalence of transsexualism reported in the literature is increasing. However, it is still very low and is mainly based on individuals attending clinical services and so does not provide an overall picture of prevalence in the general population. However, this study should be considered as a starting point and the field would benefit from more rigorous epidemiological studies acknowledging current changes in the classification system and including different locations worldwide.

Intrauterine transfusion for fetal anemia due to red blood cell alloimmunization: 14 years experience in Leuven

OBJECTIVE

The purpose of this study is to report on the pregnancy and neonatal outcome of intrauterine transfusion (IUT) for red blood cell (RBC-)alloimmunization.

MATERIAL AND METHODS

Retrospective cohort study of all IUT for RBC-alloimmunization in the University Hospital of Leuven, between January 2000 and January 2014. The influence of hydrops, gestational age and technique of transfusion on procedure related adverse events were examined.

RESULTS

135 IUTs were performed in 56 fetuses. In none of the cases fetal or neonatal death occurred. Mild adverse events were noted in 10% of IUTs, whereas severe adverse events occurred in 1.5%. Hydrops and transfusion in a free loop were associated with an increased risk of adverse events whereas gestational age (GA) at transfusion after 34 weeks was not. Median GA at birth was 35.6 weeks and 9% was born before 34 weeks. Besides phototherapy 65.4% required additional neonatal treatment for alloimmune anemia. Non-hematologic complications occurred in 23.6% and were mainly related to preterm birth.

CONCLUSION

In experienced hands, IUT for RBC-alloimmunization is a safe procedure in this era. Patients should be referred to specialist centers prior to the development of hydrops. IUT in a free loop of cord and unnecessary preterm birth are best avoided.

Rodent animal models of delayed bone healing and non-union formation: a comprehensive review

Despite the growing knowledge on the mechanisms of fracture healing, delayed healing and non-union formation remain a major clinical challenge. Animal models are needed to study the complex process of normal and impaired fracture healing and to develop new therapeutic strategies. Whereas in the past mainly large animals have been used to study normal and impaired fracture healing, nowadays rodent models are of increasing interest. New osteosynthesis techniques for rat and mice have been developed during the last years, which allowed for the first time stable osteosynthesis in these animals comparable to the standards in large animals and humans. Based on these new implants, different models in rat and mice have been established to study delayed healing and non-union formation. Although in humans the terms delayed union and non-union are well defined, in rodents definitions are lacking. However, especially in scientific studies clear definitions are necessary to develop a uniform scientific language and allow comparison of the results between different studies. In this consensus report, we define the basic terms "union", "delayed healing" and "non-union" in rodent animal models. Based on a review of the literature and our own experience, we further provide an overview on available models of delayed healing and non-union formation in rats and mice. We further summarise the value of different approaches to study normal and delayed fracture healing as well as non-union formation, and discuss different methods of data evaluation.

[Factor structure of the German version of the BIS/BAS Scales in a population-based sample]

BACKGROUND

The Behavioural Inhibition System/Behavioural Activation System Scale (BIS/BAS-Scales) developed by Carver and White 1 is a self-rating instrument to assess the dispositional sensitivity to punishment and reward. The present work aims to examine the factor structure of the German version of the BIS/BAS-Scales.

MATERIAL AND METHODS

In a large German population-based sample (n = 1881) the model fit of several factor models was tested by using confirmatory factor analyses.

RESULTS

The best model fit was found for the 5-factor model with two BIS (anxiety, fear) and three BAS (drive, reward responsiveness, fun seeking) scales, whereas the BIS-fear, the BAS-reward responsiveness, and the BAS-fun seeking subscales showed low internal consistency. The BIS/BAS scales were negatively correlated with age, and women reported higher BIS subscale scores than men.

CONCLUSION

Confirmatory factor analyses suggest a 5-factor model. However, due to the low internal reliability of some of the subscales the use of this model is questionable.

The impact of the voice in relation to psychosomatic well-being after education in female student teachers: a longitudinal, descriptive study

OBJECTIVE

Voice handicap in relation to psychosomatic well-being after education in female student teachers.

METHODS

A longitudinal survey among 90 female students using Voice Handicap Index and Symptom Check List-90 at the start and end of education.

RESULTS

Student teachers in fourth grade showed lower VHI Total and lower SCL-90 Total scores compared to first grade. Students with higher VHI scores in fourth grade had higher risk on "Anxiety" (OR=1.8 to 4.8), "Agoraphobia" (OR=1.9 to 3.9) and "Insufficiency in thinking and acting" (OR=1.6 to 3.2). Students with respectively higher VHI-Total and VHI-Emotional subscale scores had higher risk on "Depression" (OR=1.7, resp. 3.9), "Interpersonal sensitivity and mistrust" (OR=1.6, resp. 3.2), "Hostility" (OR=1.7, resp. 2.1) and SCL-Total (OR=3.1 resp. 4.0).

CONCLUSIONS

Student teachers at the end of education showed more well-being and were less vocally handicapped. A tendency for a positive relation between higher emotional voice handicap and more psychosomatic complaints was found.

SUGGESTIONS

The VHI has proven to be useful and special attention to VHI Emotional scale is advised in screening. This study might have implications for the preventive care and a multi-dimensional approach with attention to physical, mental and social voice care in future teachers is suggested. In contrast to the group score comparisons a closer look at individual reports on specific VHI items in relation to SCL-90 may be fruitful to detect tendencies. Student teachers can benefit from interdisciplinary collaboration between a psychologist and voice therapist in reducing psychosocial risk factors.

[Meaningful 'romming' (routine outcome monitoring): seeking a balance between userfriendliness and clinical relevance]

BACKGROUND

In the course of the last few years several ROM systems have been developed in which the measurements and feedback are restricted to the therapy outcome in terms of symptom reduction. In these ROM systems the emphasis is on the user-friendliness and on the ease with which the measurements can be implemented in clinical practice. However, research shows that many therapists and clients consider that the measurement of symptom reduction is too simplistic.

AIM

To develop a ROM system that is therapeutically more relevant.

METHOD

We describe the development and implementation of the Leuven Systematic Case study Protocol.

RESULTS

In this multidimensional and multimodal monitoring system the emphasis is on the therapeutic relevance of 'romming:' not simply in terms of symptom reduction, but also in terms of processes of change and growth-orientated processes. In addition, the monitoring system takes into account the unique characteristics of client and therapist and the synergy existing between them.

CONCLUSION

Not only do therapists have to learn to deal with the practical aspects of 'romming', they also need to be trained and supported so that they can deal adequately with a more explicit evaluation and feedback 'culture'.

Small animal bone healing models: standards, tips, and pitfalls results of a consensus meeting

Small animal fracture models have gained increasing interest in fracture healing studies. To achieve standardized and defined study conditions, various variables must be carefully controlled when designing fracture healing experiments in mice or rats. The strain, age and sex of the animals may influence the process of fracture healing. Furthermore, the choice of the fracture fixation technique depends on the questions addressed, whereby intra- and extramedullary implants as well as open and closed surgical approaches may be considered. During the last few years, a variety of different, highly sophisticated implants for fracture fixation in small animals have been developed. Rigid fixation with locking plates or external fixators results in predominantly intramembranous healing in both mice and rats. Locking plates, external fixators, intramedullary screws, the locking nail and the pin-clip device allow different degrees of stability resulting in various amounts of endochondral and intramembranous healing. The use of common pins that do not provide rotational and axial stability during fracture stabilization should be discouraged in the future. Analyses should include at least biomechanical and histological evaluations, even if the focus of the study is directed towards the elucidation of molecular mechanisms of fracture healing using the largely available spectrum of antibodies and gene-targeted animals to study molecular mechanisms of fracture healing. This review discusses distinct requirements for the experimental setups as well as the advantages and pitfalls of the different fixation techniques in rats and mice.

A novel method for lateral callus distraction and its importance for the mechano-biology of bone formation

We introduce a novel method of lateral callus distraction for bone formation, which avoids the conventional splitting and weakening of bones. At the medial aspect of the sheep tibia the periosteum was resected and small holes were drilled into the cortex to connect the bone surface with the marrow. A distraction device with a hydroxyapatite-coated titanium plate was fixed over the drilled area. After 10 days latency the plate was distracted perpendicular to the bone's long axis twice a day by 0.27 mm for 10 days. The newly formed tissue was then allowed 50 days of maturation. In a control group the plate was fixed 5.4mm distant from the bone surface. After 70 days all sheep were sacrificed and investigated histo-morphologically and with pQCT. Significantly more bone had developed between the lateral bone surface and the plate in the distraction group compared to the control group. There was exclusively intra-membranous bone formation with trabeculae oriented in the direction of the applied distraction. The main calcification occurred weeks after the last distraction. In conventional callus distraction the tissue strain caused by distraction is superimposed by the tissue deformation due to the deformation of the fixation device. In contrast, in the newly introduced lateral callus distraction method pure uniaxial strain occurs. From a mechano-biological point of view these results suggest that pure uniaxial strain induces exclusively intra-membranous bone formation. Furthermore, it shows that the anabolic effect of tissue strain is present even 50 days after the last stimulation by distraction.

Deficiencies of folate and vitamin B12 do not affect fracture healing in mice

PURPOSE

Recently, hyperhomocysteinemia has been shown to be associated with impaired fracture healing in mice. The main causes for hyperhomocysteinemia are deficiencies of folate and vitamin B12. However, there is no information on whether deficiencies of these B vitamins are affecting bone repair, too.

METHODS

We used two groups of mice to investigate the impact of folate and vitamin B12 deficiency on fracture healing: mice of the first group were fed a folate- and vitamin B12-deficient diet (n=14), while mice of the second group received an equicaloric control diet (n=13). Four weeks after stabilizing a closed femur fracture, bone repair was analyzed by histomorphometry and biomechanical testing. In addition, serum concentrations of homocysteine, folate, vitamin B12, the bone formation marker osteocalcin (OC), and the bone resorption marker collagen I C-terminal crosslaps (CTX) were measured.

RESULTS

Serum analyses revealed significantly decreased concentrations of folate and vitamin B12 in animals fed the folate- and vitamin B12-deficient diet when compared to controls. This was associated with a moderate hyperhomocysteinemia in folate- and vitamin B12-deficient mice, while no hyperhomocysteinemia was found in controls. Three-point bending tests showed no significant differences in callus stiffness between bones of folate- and vitamin B12-deficient animals and those of control animals. In accordance, the histomorphometric analysis demonstrated a comparable size and tissue composition of the callus, and also serum markers of bone turnover did not differ significantly between the two groups.

CONCLUSIONS

We conclude that folate and vitamin B12 deficiency does not affect bone repair in mice.

Group I afferent pathway contributes to functional knee stability

The hamstring reflex response has been suggested to play a substantial role in knee joint stabilization during anterior tibial translation. The present study was performed to determine which afferent pathways contribute to the hamstring reflex as well as the potential effects of specific afferent pathways on functional knee stability. Short- and medium-latency hamstring reflexes (SLR and MLR) were evoked by anterior tibial translation in 35 healthy subjects during standing with 30 degrees knee flexion. Nerve cooling, tizanidine, and ischemia were employed to differentiate afferent pathways. Two hours of thigh cooling (n = 10) resulted in a significant increase in MLR latency and, to a lesser extent, SLR latency. No significant changes were recorded in reflex sizes or maximum tibial translation. The ingestion of tizanidine (n = 10), a suppressor of group II afferents, strongly reduced the MLR size while SLR size or latency of both reflex responses was not significantly affected. Maximum tibial translation was unchanged [5.3 +/- 1.9 to 4.8 +/- 2 (SD) mm; P = 0.410]. Ischemia in the thigh (n = 15) led to a highly significant depression in SLR size (89 +/- 4%; P < 0.001) but only a slight and not significant decline of MLR size. In these subjects maximum tibial translation increased significantly (6.9 +/- 1.6 to 9.4 +/- 3.2 mm; P = 0.028). It is concluded that the hamstring SLR is mediated by Ia afferents, while group II afferents mainly contribute to the MLR. Suppression of SLR may increase maximum anterior tibial translation, thus indicating a possible functional role of Ia afferents in knee joint stabilization.

Hyperhomocysteinemia is associated with impaired fracture healing in mice

Hyperhomocysteinemia (HHCY) has been shown to disturb bone metabolism and to increase the incidence of osteoporosis and osteoporotic fractures. However, there is a complete lack of information on whether these metabolic alterations affect bone repair. The aim of this study was to analyze the impact of HHCY on fracture healing. One group of mice was fed a homocystine-supplemented diet (n = 12), whereas another group received the accordant standard diet for control (n = 13). Four weeks after the stable fixation of a closed femoral fracture, animals were killed to prepare bones for histomorphometric and biomechanical analyses. In addition, blood samples were obtained to evaluate serum concentration of homocysteine (HCY). Quantitative analysis of blood samples revealed severe HHCY as indicated by significantly increased serum concentrations of HCY in animals fed the homocystine-supplemented diet (102.2 +/- 64.5 micromol/l) compared to controls (2.8 +/- 1.5 micromol/l). Biomechanical evaluation of bone repair revealed significantly decreased bending stiffness of the femora of homocystine-fed animals (45.5 +/- 18.2 N/mm) compared with controls (64.6 +/- 15.8 N/mm). Histomorphometric analysis demonstrated a slightly smaller callus diameter in HHCY animals but no significant differences in the tissue composition of the callus. In conclusion, the homocystine-supplemented diet leads to severe HHCY, which is associated with an impaired biomechanical quality of the healing bone.

[Possibilities of geometric X-ray examination of the pelvis for partial pelvis replacement]

Patients with tumors of the pelvis, which cannot be treated by chemotherapy or radiation, must undergo hemipelvectomy. The postoperative prosthetic treatment was difficult und not always sufficient. So, a complete internal hemipelvectomy was done by replacement of an artificial part of half pelvis. Before the operation it was necessary to know the measurements of the pelvis exactly. This was done by taking X-ray pictures in anterior--posterior, lateral and axial direction which brought out the relevant diameters for the construction of the artificial pelvis. By using the Computer-Tomography we could get exact slices of the pelvis in the transversal plane. The slices were centrally positioned, then the model was covered with modelling-mass. The result was an exact positive feature of the pelvis which must be replaced.

Can a modified interspinous spacer prevent instability in axial rotation and lateral bending? A biomechanical in vitro study resulting in a new idea

BACKGROUND

Interspinous spacers are mainly used to treat lumbar spinal stenosis and facet arthrosis. Biomechanically, they stabilise in extension but do not compensate instability in axial rotation and lateral bending. It would therefore be desirable to have an interspinous spacer available, which provides for more stability also in these two planes. At the same time, the intervertebral disc should not completely be unloaded to keep it viable. To meet these requirements, a new version of the Coflex interspinous implant was developed, called "Coflex rivet", which can be more rigidly attached to the spinous processes. The aim was to investigate whether this new implant compensates instability but still allows some load to be transferred through the disc.

METHODS

Twelve human lumbar spine segments were equally divided into two groups, one for Coflex rivet and one for the original Coflex implant. The specimens were tested for flexibility under pure moment loads in the three main planes. These tests were carried out in the intact condition, after creation of a destabilising defect and after insertion of either of the two implants. Before implantation, the interspinous spacers were equipped with strain gauges to measure the load transfer.

FINDINGS

Compared to the defect condition, both implants had a strong stabilising effect in extension (P<0.05). Coflex rivet also strongly stabilised in flexion and to a smaller degree in lateral bending and axial rotation (P<0.05). In contrast, in these three loading directions, the original Coflex implant could not compensate the destabilising effect of the defect (P>0.05). The bending moments transferred through the implants were highest in extension and flexion. Yet, they were no more than 1.2 Nm in median.

INTERPRETATION

The new Coflex rivet seems be a suitable option to compensate instability. Its biomechanical characteristics might even make it suitable as an adjunct to fusion, which would be a new indication for this type of implant.

Biomechanical comparison of two side plate fixation techniques in an unstable intertrochanteric osteotomy model: Sliding Hip Screw and Percutaneous Compression Plate

BACKGROUND

Our objective was to determine the biomechanical primary stability of two different side plate fixation devices in an unstable intertrochanteric cadaver model: the Sliding Hip Screw with an additional derotation screw was compared with the Percutaneous Compression Plate.

METHODS

Eight pairs of human cadaver femurs were tested for comparison of the primary stability of the two implants in two modes: (a) cyclic loading up to 200 N, 400 N, 600 N, 800 N, and 1000 N, respectively. In vitro combined axial and bending loads were applied. Angular displacements of the proximal head fragment during loading were recorded in rotational, varus-valgus, and anterior-posterior directions. (b) The load to failure was determined.

FINDINGS

Specimens fixed with the Percutaneous Compression Plate showed higher displacements in the varus during loading up to 200 N (P=0.033), and 400 N (P=0.001), compared to the Sliding Hip Screw. A similar tendency was observed for higher loads. The Percutaneous Compression Plate allowed more external rotation of the proximal fragment only at loads up to 800 N (P=0.019). No statistical difference could be found for the slight migrations in the posterior direction. Load to failure also revealed no statistical difference between the two implants.

INTERPRETATION

The Percutaneous Compression Plate as a double-axis fixation device with a sliding capability allows higher displacements in the varus direction and also in external rotation at 800 N loading compared to the Sliding Hip Screw as a single-axis fixation device combined with an additional derotation screw. While both implants are successful used in clinical practice, this should be considered in treatment of unstable intertrochanteric fractures with inferior comminution in osteoporotic patients.

Influence of extracellular osmolarity and mechanical stimulation on gene expression of intervertebral disc cells

Intervertebral discs (IVD) have a higher extracellular osmolarity than most other tissues; moreover their osmolarity changes by around 25% during each diurnal cycle. In this study, changes in aggrecan, collagen I and collagen II expression of IVD cells were examined after exposure to osmotic environment alterations or mechanical stimulation under different osmotic conditions. Human and bovine IVD cells seeded in three-dimensional (3D) collagen type I matrices were cultured under hypo-osmotic (300 mOsm), iso-osmotic (400 mOsm), or hyperosmotic (500 mOsm) conditions. Osmolarity-induced changes in gene expression of IVD cells were measured after 5 days. Load-induced changes in gene expression under the different osmotic conditions were measured after application of hydrostatic pressure (0.25 MPa, 0.1 Hz, 30 min) or cyclic strain (4%, 1 Hz, 24 h). The results showed that IVD cells respond strongly to changes in the osmotic environment by altering mRNA expression. Human cells cultured over 5 days increased expression of aggrecan and collagen II in both nucleus and annulus cells under increasing osmolarity. In contrast, collagen I expression was inhibited at high osmolarity in both cell types. Mechanically induced alterations in gene expression appear to have only modest effects on matrix protein expression, but the same stimulus partly resulted in an inhibition or stimulation of gene expression, depending on the osmotic conditions. This study showed that the osmotic environment does not only have an appreciable effect on gene expression but also affects responses to mechanical stimuli. This suggests that the osmotic conditions cannot be ignored when examining physiological and pathological behavior of IVD cells.

The influence of meniscal lesions on reflex activity in the hamstring muscles

Meniscal lesions are among the most common knee injuries and substantially affect the mechanical function of the knee joint. In addition, the presence of mechanoreceptors in the meniscus suggests that the menisci are also involved in the sensorimotor control of the knee. The objective of this study was to investigate the influence of an isolated meniscal lesion on the reflex behaviour of the hamstring muscles, which are involved in the sensorimotor control of the knee joint. For this purpose, we mechanically induced tibial translation in 19 patients in a standing position and analysed the biphasic response of the hamstrings consisting of a short-latency response (SLR) and a medium-latency response (MLR). Moreover, we determined anterior tibial translation. A comparison of electromyographic data for the healthy legs versus the injured legs showed no significant differences in either SLRs or MLRs. Although there was a tendency to an increase in tibial translation, no significant difference between the legs in anterior tibial translation was found. In conclusion, our experimental work did not reveal any substantial effects of a meniscal lesion on the reflex behaviour of the hamstrings. Our data suggest that the menisci appear to play only a minor role for the sensorimotor induced anterior posterior knee stability.

VEGF producing bone marrow stromal cells (BMSC) enhance vascularization and resorption of a natural coral bone substitute

Bone graft substitutes often exhibit poor bone regeneration in large defects because of inadequate vascularization. Studies have shown that if blood supply is compromised, application of osteogenic factors alone could not induce successful healing. This study was to evaluate the effects of vascular endothelial growth factor, which combined with a coralline scaffold, on vascularization, scaffold resorption and osteogenesis in a rabbit radius critical size defect model. The scaffold was either coated with a control-plasmid DNA (group 1), coated with VEGF-plasmid DNA (group 2), loaded with mesenchymal stem cells (BMSC) transfected with control plasmid (group 3) or with both stem cells and the VEGF plasmid (group 4). X-rays were taken every 4 weeks up to week 16, when animals were euthanized. The volume of new bone was measured by mu-CT scans and blood vessels were counted after anti-CD31 staining of endothelial cells. The results from the solitary VEGF- and VEGF-transfected cells (groups 2 and 4) demonstrated significantly enhanced vascularization, osteogenesis and resorption of the carrier when compared to the control group. The highest degree of osteogenesis was found when the carrier was loaded with BMSC (group 3), whereas VEGF-transfected cells led to the highest vascularization and fastest resorption of the bone substitute. Additionally, VEGF-transfected BMSC led to a more homogenous vascularization of the defect. The results indicate that VEGF can be a helpful factor to improve healing in large bone defects, in which bone substitutes will otherwise not be vascularized and replaced by fresh bone.

The non-steroidal anti-inflammatory drug diclofenac reduces appearance of osteoblasts in bone defect healing in rats

INTRODUCTION

Non-steroidal anti-inflammatory drug (NSAID) is well known to significantly delay fracture healing. Results from in vitro studies implicate an impairment of osteoblast proliferation due to NSAIDs during the initial stages of healing. We studied whether diclofenac, a non-selective NSAID, also impairs appearance of osteoblasts in vivo during the early phase of healing (at 10 days).

MATERIALS AND METHODS

Two defects (Ø 1.1 mm) were drilled within distal femurs of 20 male Wistar rats. Ten rats received diclofenac continuously; the other obtained a placebo until sacrificing at 10 days. Osteoblast proliferation was assessed by cell counting using light microscopy, and bone mineral density (BMD) was measured using pQCT.

RESULTS

Osteoblast counts from the centre of bone defect were significantly reduced in the diclofenac group (median 73.5 +/- 8.4 cells/grid) compared to animals fed with placebo (median 171.5 +/- 13.9 cells/grid). BMD within the defect showed a significant reduction after diclofenac administration (median 111.5 +/- 9.3 mg/cm(3)) compared to the placebo group (median 177 +/- 45.4 mg/cm(3)).

CONCLUSION

The reduced appearance of osteoblasts in vivo implicates an inhibiting effect of diclofenac on osteoblasts at a very early level of bone healing. The inhibition of proliferation and migration of osteoblasts, or differentiation from progenitor cells, is implicated in the delay of fracture healing after NSAID application.

The effects of non-steroidal anti-inflammatory drug application on incisional wound healing in rats

OBJECTIVE

There is evidence that non-steroidal anti-inflammatory drugs (NSAIDs) delay both epithelialisation and angiogenesis in the early phases of wound healing because of an antiproliferative effect. We investigated the influence of diclofenac, a non-selective NSAID, on incisional wound healing.

METHOD

Ten male Wistar rats were given 5 mg diclofenac per kg bodyweight per day; 10 rats were given placebo pellets. After 10 days, unimpaired healing occurred independently of drug treatment both macroscopically and microscopically. Histomorphometry revealed a significant reduction (p = 0.006) in fibroblasts after diclofenac application (median 3 166 cells per mm2) compared with the placebo group (median 3940 cells per mm2). Epidermal thickness was not statistically different between the two groups.

RESULTS

Diclofenac diminished the amount of fibroblasts in connective tissue, reflecting the known antiproliferative effect of NSAIDs on fibroblasts. Clinical healing was not affected.

CONCLUSION

We recommend short-term diclofenac application for post-surgical and post-traumatic patients with wounds who would benefit from its antiphlogistic and analgesic effect. However, if wound healing is disturbed, the negative effect of diclofenac on fibroblasts should be considered. This is particularly relevant for patients with chronic wounds or conditions such as diabetes which can delay wound healing.

1[alpha],25-dihydroxyvitamin D(3) enhances annexin II dependent proliferation of osteoblasts

Cells experience a variety of physiological and non-physiological stresses and consequently have appropriate mechanisms to deal with such deviations from homeostasis. Particularly subject to mechanical stress and shear forces are the cells that make up the bones. Osteoblastic cells can interpret this stress as a stimulus for proliferation; however, the molecular mechanisms underlying this phenomenon are poorly understood. We have identified annexin II as being specifically upregulated in mechanically stressed osteoblasts and found that increased levels of this protein are necessary for 1[alpha],25-dihydroxyvitamin D(3) mediated augmentation of the proliferative response of osteoblasts after mechanical stress. Our data demonstrate a novel interaction between 1[alpha],25-dihydroxyvitamin D(3) and annexin II in the proliferative response of osteoblasts as well as a novel function for annexin II in the stress response. These findings may offer new therapeutic opportunities for conditions that require regenerative osteoblastic activity such as osteoporosis.

Changes in Stretch Reflex Excitability Are Related to “Giving Way” Symptoms in Patients With Anterior Cruciate Ligament Rupture

A rupture of the anterior cruciate ligament (ACL) usually leads to an altered stretch reflex excitability of the thigh muscles that stabilize the knee. The purpose of this study was to quantitatively assess reflex activity in the m. semitendinosus/semimembranosus after anterior tibial translation in 21 patients with isolated ACL ruptures. The patients were divided into a group with “giving way” symptoms (noncopers, n = 12) and a group without “giving way” symptoms (copers, n = 9). While the patients were standing upright with 30° knee flexion, a force of 300 N was applied to the knee to induce posterior–anterior tibial translation. Activity of m. semitendinosus/semimembranosus was measured using surface electromyography (EMG). A linear potentiometer was placed on the tibial tuberosity and measured maximum tibial translation during standing (i.e., functional condition). In addition, knee laxity was assessed with a KT1000 arthrometer under passive conditions. After ACL rupture, the short-latency response (SLR) latency remained unchanged ( P = 0.21), whereas for the medium-latency response (MLR) it was significantly longer ( P < 0.001). Significantly longer MLR latencies were noted for noncopers compared with copers ( P < 0.01), whereas SLR latencies were similar. Significant differences between healthy and injured legs were noted after tibial translations using KT1000 ( P < 0.001) and during stance ( P < 0.001). Mechanical knee instability was found to be unchanged between copers and noncopers (KT1000: P = 0.97; tibial translation: P = 0.31). These results indicate that ACL rupture is associated with altered stretch reflex excitability, which may lead to “giving way” symptoms, and that altered stretch reflex excitability may be more important for the development of “giving way” than the mechanical instability of the knee.

A novel GABRG2 mutation associated with febrile seizures

Mutations in the gene encoding the gamma2 subunit of the gamma-aminobutyric acid type A receptor (GABRG2) have been reported to cause childhood absence epilepsy (CAE), febrile seizures (FS), and generalized epilepsy with FS plus (GEFS+). The authors analyzed GABRG2 in 47 unrelated patients with CAE, FS, and GEFS+ and identified a novel mutation that cosegregated with FS. Electrophysiologic studies demonstrated altered current desensitization and reduced benzodiazepine enhancement in mutant receptors.

Biomechanical performance of the new BeadEx implant in the treatment of osteoporotic vertebral body compression fractures: restoration and maintenance of height and stability

BACKGROUND

Vertebral compression fractures are counted among the most common complications of osteoporosis. For treatment, a new, alternative implant has been developed (BeadEx, Expandis, Hof HaCarmel, Israel). The aim of the present in vitro study was to evaluate whether this implant is able to restore the initial height and three-dimensional stability after fracture and whether it is able to maintain this height and stability during complex cyclic loading.

METHODS

The BeadEx implant consists of small titanium rolls, which are pressed into the vertebral body through specially designed, hollow pedicle screws. The height and the three-dimensional flexibility of 18 bisegmental spine specimens (nine T12-L2, nine L3-L5) was measured, first, before and after creating a wedge compression fracture at the middle vertebral body (L1 resp. L4), second, after treatment of the fracture, and, third, during and after complex cyclic loading. The fractures were treated either with BeadEx plus internal fixator, BeadEx plus bone cement or vertebroplasty for comparison.

FINDINGS

The height before fracture could almost be restored by BeadEx plus bone cement but not by BeadEx plus fixator and vertebroplasty. The total height loss after cyclic loading was smallest with BeadEx plus bone cement (in median -4.7mm with respect to the intact specimens) but -6.2mm with BeadEx plus fixator and -7.8mm with vertebroplasty. The three-dimensional stability of the specimens was clearly higher if treated with BeadEx plus fixator than with BeadEx plus bone cement or vertebroplasty.

INTERPRETATION

From a biomechanical point of view, BeadEx plus bone cement can be recommended as an alternative to vertebroplasty in the treatment of osteoporotic vertebral body fractures. BeadEx plus fixator can be recommended if additional stability is needed.

In vitro fixator rod loading after transforaminal compared to anterior lumbar interbody fusion

BACKGROUND

Cages are commonly used to assist lumbar interbody fusion. They are implanted from various approaches. In many cases internal fixators are added to provide sufficient stability. However, how the rods of these fixators are loaded and whether the kind of approach affects these loads is still unknown. The aim of this in vitro study therefore was to determine the loads acting on fixator rods and cages after anterior compared to transforaminal lumbar interbody fusion.

METHODS

Six intact human lumbar spine specimens (L1-5) were loaded in a spine tester with pure moments (+/-7.5 N m) in the frontal, sagittal and transverse plane. Loading was repeated, first, after the segments L2-3 and L4-5 were instrumented either with an anterior or a transforaminal lumbar interbody fusion cage "stand alone" and, second, after additional stabilisation with an internal fixator. The rods of the fixator and the four "corners" of the cages were instrumented with strain gauges.

FINDINGS

The loads transmitted through the rods were highest in lateral bending. In this loading direction an axial distraction force of in median up to 140 N, an axial compression force of up to 100 N, and a resultant bending moment of up to 1.1 N m were measured in each rod. These loads tended to be lower for the anterior compared to the transforaminal approach. For comparison, the load applied was +/-7.5 N m. The axial strains recorded in the four "corners" of the cages considerably varied from one specimen to the other. Differences in cage strain between the two approaches could not be detected.

INTERPRETATION

The loads acting on the rods of the fixator were small compared to the load that was applied. Thus, other structures such as the cages or the facet joints still play an important role in load transfer. The type of approach (anterior or transforaminal) had only little effect on the loading of the rods. This also applies to the local loading of the cages, which probably more depends on the fit between cage and endplates and on the local stiffness properties of the adjacent vertebral bodies.

The usefulness of experience sampling in understanding the urge to move in anorexia nervosa

BACKGROUND

Physical hyperactivity has often been described in anorexia nervosa (AN) patients but up until now in-depth research has been scarce. Experience sampling methodology (ESM), a structured diary technique assessing momentary mental state at random times during the day, may be useful in studying hyperactivity in AN.

METHODS

In two single case reports, ESM was used to investigate the variation across time of the urge to move in relation to potentially relevant eliciting conditions such as positive and negative emotions, weight preoccupation and attractiveness.

RESULTS

Frequency distribution of the involved variables indicated substantial individual differences between patients. While both patients' tendency to be hyperactive was positively related to their weight preoccupation and negative emotions, in only one patient, the urge to move turned out to be significantly related to (the absence of) positive emotions.

CONCLUSIONS

ESM can be useful to test whether general theories of psychopathology apply to specific patients, and it may be conceived as an individually tailored approach to self-monitoring. As such, it may guide the clinician to devise therapeutic interventions in particular patients.