New perspectives on the development of muscle contractures following central motor lesions.

Muscle contractures are common in patients with central motor lesions, but the mechanisms responsible for the development of contractures are still unclear. Increased or decreased neural activation, protracted placement of a joint with the muscle in a short position and muscle atrophy have been suggested to be involved, but none of these mechanisms are sufficient to explain the development of muscle contractures alone. Here we propose that changes in tissue homeostasis in the neuromuscular-tendon-connective tissue complex is at the heart of the development of contractures, and that an integrated physiological understanding of the interaction between neural, mechanical and metabolic factors, as well as genetic and epigenetic factors, is necessary in order to unravel the mechanisms that result in muscle contractures. We hope thereby to contribute to a reconsideration of how and why muscle contractures develop in a way which will open a window towards new insight in this area in the future.

Applicability of contrast-enhanced ultrasound in the diagnosis of plantar fasciitis.

Contrast-enhanced ultrasound (CEUS) is used to visualize the microvascularization in various tissues. The purpose of this study was to investigate whether CEUS could be used to visualize the microvascular volume (MV) in the plantar fascia, and to compare the method to clinical symptoms and B-mode ultrasound (US) in patients with plantar fasciitis (PF). Twenty patients with unilateral PF were included and were divided by US in insertional thickening (10), midsubstance thickening (5), and no US changes (5). The MV was measured simultaneously in both heels. Four areas in the plantar fascia and plantar fat pad were measured independently by two observers. Inter- and intra-observer correlation analyses were performed. The asymptomatic heels showed a constantly low MV, and for the whole group of patients, a significantly higher MV was found in the symptomatic plantar fascia and plantar fat pad. Inter-observer correlation as well as intra-observer agreement was excellent. The MV in the plantar fascia and plantar fat pad can be measured reliably using CEUS, suggesting that it is a reproducible method to examine patients with plantar fasciitis.

Three hundred and seventy-two novel HLA class II alleles identified in potential hematopoietic stem cell donors from Germany, the United States, and Poland.

We have characterized 372 novel human leukocyte antigen (HLA) class II alleles identified in newly registered stem cell donors, this includes 281 HLA-DRB1 alleles, 89 HLA-DQB1 alleles and 2 HLA-DPB1 alleles. Most novel alleles were single nucleotide variants when compared to their respective most homologous alleles. In 66.4% of all novel alleles non-synonymous nucleotide variations were identified, in 30.4% synonymous substitutions and in 3.2% nonsense mutations. Ninty-three (25.0%) novel alleles were found in several individuals; most often these were novel HLA-DRB1 alleles. Lastly, we underline the importance of recruiting ethnic minority donors in countries such as Germany and the United States, as novel alleles were frequently found among these groups.

Identification of 2127 new HLA class I alleles in potential stem cell donors from Germany, the United States and Poland.

We describe 2127 new human leukocyte antigen (HLA) class I alleles found in registered stem cell donors. These alleles represent 28.9% of the currently known class I alleles. Comparing new allele sequences to homologous sequences, we found 68.1% nonsynonymous nucleotide substitutions, 28.9% silent mutations and 3.0% nonsense mutations. Many substitutions occurred at positions that have not been known to be polymorphic before. A large number of HLA alleles and nucleotide variations underline the extreme diversity of the HLA system. Strikingly, 156 new alleles were found not only multiple times, but also in carriers of various parentage, suggesting that some new alleles are not necessarily rare. Moreover, new alleles were found especially often in minority donors. This emphasizes the benefits of specifically recruiting such groups of individuals.

Comparative validation of computer programs for haplotype frequency estimation from donor registry data.

Estimation of human leukocyte antigen (HLA) haplotype frequencies from unrelated stem cell donor registries presents a challenge because of large sample sizes and heterogeneity of HLA typing data. For the 14th International HLA and Immunogenetics Workshop, five bioinformatics groups initiated the 'Registry Diversity Component' aiming to cross-validate and improve current haplotype estimation tools. Five datasets were derived from different donor registries and then used as input for five different computer programs for haplotype frequency estimation. Because of issues related to heterogeneity and complexity of HLA typing data identified in the initial phase, the same five implementations, and two new ones, were used on simulated datasets in a controlled experiment where the correct results were known a priori. These datasets contained various fractions of missing HLA-DR modeled after European haplotype frequencies. We measured the contribution of sampling fluctuation and estimation error to the deviation of the frequencies from their true values, finding equivalent contributions of each for the chosen samples. Because of patient-directed activities, selective prospective typing strategies and the variety and evolution of typing technology, some donors have more complete and better HLA data. In this setting, we show that restricting estimation to fully typed individuals introduces biases that could be overcome by including all donors in frequency estimation. Our study underlines the importance of critical review and validation of tools in registry-related activity and provides a sustainable framework for validating the computational tools used. Accurate frequencies are essential for match prediction to improve registry operations and to help more patients identify suitably matched donors.

16(th) IHIW: global analysis of registry HLA haplotypes from 20 million individuals: report from the IHIW Registry Diversity Group.

This project has the goal to validate bioinformatics methods and tools for HLA haplotype frequency analysis specifically addressing unique issues of haematopoietic stem cell registry data sets. In addition to generating new methods and tools for the analysis of registry data sets, the intent is to produce a comprehensive analysis of HLA data from 20 million donors from the Bone Marrow Donors Worldwide (BMDW) database. This report summarizes the activity on this project as of the 16IHIW meeting in Liverpool.

Increased mast cell numbers in a calcaneal tendon overuse model.

Tendinopathy is often discovered late because the initial development of tendon pathology is asymptomatic. The aim of this study was to examine the potential role of mast cell involvement in early tendinopathy using a high-intensity uphill running (HIUR) exercise model. Twenty-four male Wistar rats were divided in two groups: running group (n = 12); sedentary control group (n = 12). The running-group was exposed to the HIUR exercise protocol for 7 weeks. The calcaneal tendons of both hind limbs were dissected. The right tendon was used for histologic analysis using Bonar score, immunohistochemistry, and second harmonic generation microscopy (SHGM). The left tendon was used for quantitative polymerase chain reaction (qPCR) analysis. An increased tendon cell density in the runners were observed compared to the controls (P = 0.05). Further, the intensity of immunostaining of protein kinase B, P = 0.03; 2.75 ± 0.54 vs 1.17 ± 0.53, was increased in the runners. The Bonar score (P = 0.05), and the number of mast cells (P = 0.02) were significantly higher in the runners compared to the controls. Furthermore, SHGM showed focal collagen disorganization in the runners, and reduced collagen density (P = 0.03). IL-3 mRNA levels were correlated with mast cell number in sedentary animals. The qPCR analysis showed no significant differences between the groups in the other analyzed targets. The current study demonstrates that 7-week HIUR causes structural changes in the calcaneal tendon, and further that these changes are associated with an increased mast cell density.

The effect of acute exercise on collagen turnover in human tendons: influence of prior immobilization period.

Mechanical loading of human tendon stimulates collagen synthesis, but the relationship between acute loading responses and training status of the tendon is not clear. We tested the effect of prolonged load deprivation on the acute loading-induced collagen turnover in human tendons, by applying the same absolute load to a relative untrained Achilles tendon (2-week immobilization period prior to acute loading) and a habitually loaded contra-lateral Achilles tendon, respectively, within the same individuals. Eight untrained, healthy males had one lower limb totally immobilized for 2 weeks, whereas the contra-lateral leg was used habitually. Following the procedure both Achilles tendons and calf muscles were loaded with the same absolute load during a 1-h treadmill run. Tissue collagen turnover was measured by microdialysis performed post-immobilization but pre-exercise around both Achilles tendons and compared to values obtained by 72-h post-exercise. Power Doppler was used to monitor alterations in intratendinous blood flow velocity of the Achilles tendon and MRI used to quantitate changes in tendon cross-section area. Acute loading resulted in an increased collagen synthesis 72 h after the run in both Achilles tendons (p < 0.05) with no significant difference. No signs of acute tendon overloading were demonstrated by Power Doppler, and tendon cross-section area did not change as a result of immobilization and reloading. The present study indicates that 2 weeks of tendon load deprivation is not sufficient to affect the normal adaptive response to loading determined as increased collagen synthesis of peritendinous Achilles tendon tissue in humans.

Enhanced alveolar bone loss in a model of non-invasive periodontitis in rice rats.

OBJECTIVE: The rice rat (Oryzomys palustris) develops periodontitis-like lesions when fed a diet rich in sucrose and casein (H-SC). We aimed to establish whether this model can accurately mimic the development of human periodontitis. MATERIALS AND METHODS: For this purpose, 28-day-old rice rats (15/group) were assigned to standard (STD) or H-SC diets and sacrificed after 6, 12, and 18 weeks. Jaws were processed for morphometric, histometric, histologic, histomorphometric, and micro-CT analyses. RESULTS: We found a progressive increase in horizontal alveolar bone loss (ABL) with age in maxillae of rats fed the STD diet as determined by morphometry. The H-SC diet exacerbated horizontal ABL at the palatal surface at 12 and 18 weeks. Furthermore, increased vertical ABL was detected in mandibles and maxillae of rats fed the H-SC diet for 12 and/or 18 weeks by histometry and micro-CT. Remarkably, the H-SC diet significantly increased bone remodeling at the interproximal alveolar bone of mandibles from rats fed for 6 weeks, but not in those fed for longer periods. CONCLUSIONS: These findings indicate that the H-SC diet induced a transient increase in alveolar bone remodeling, which is followed by ABL characteristic of moderate periodontitis.

Mutations in the tyrosine phosphatase CD45 gene in a child with severe combined immunodeficiency disease.

The hematopoietic-specific transmembrane protein tyrosine phosphatase CD45 functions to regulate Src kinases required for T- and B-cell antigen receptor signal transduction. So far, there have been no reports to our knowledge of a human deficiency in a tyrosine-specific phosphatase. Here, we identified a male patient with a deficiency in CD45 due to a large deletion at one allele and a point mutation at the other. The point mutation resulted in the alteration of intervening sequence 13 donor splice site. The patient presented at 2 months of age with severe combined immunodeficiency disease. The population of peripheral blood T lymphocytes was greatly diminished and unresponsive to mitogen stimulation. Despite normal B-lymphocyte numbers, serum immunoglobulin levels decreased with age. Thus, CD45 deficiency in humans results in T- and B-lymphocyte dysfunction.

Effect of administration of oral contraceptives in vivo on collagen synthesis in tendon and muscle connective tissue in young women.

Women are at greater risk than men for certain kinds of diseases and injuries, which may at least partly be caused by sex hormonal differences. We aimed to test the influence of estradiol in vivo on collagen synthesis in tendon, bone, and muscle. Two groups of young, healthy women similar in age, body composition, and exercise-training status were included. The two groups were either habitual users of oral contraceptives exposed to a high concentration of synthetic estradiol and progestogens (OC, n = 11), or non-OC-users tested in the follicular phase of the menstrual cycle characterized by low concentrations of estradiol and progesterone (control, n = 12). Subjects performed 1 h of one-legged kicking exercise. The next day collagen fractional synthesis rates (FSR) in tendon and muscle connective tissue were measured after a flooding dose of [(13)C]proline followed by biopsies from the patellar tendon and vastus lateralis in both legs. Simultaneously, microdialysis catheters were inserted in vastus lateralis and in front of the patellar tendon for measurement of insulin-like growth factor I (IGF-I) and its binding proteins. Serum NH(2)-terminal propeptide of type I collagen (PINP) and urine COOH-terminal telopeptides of type-I collagen (CTX-I) were measured as markers for bone synthesis and breakdown, respectively. Tendon FSR and PINP were lower in OC compared with control. An increase in muscle collagen FSR postexercise was only observed in control (P < 0.05). Furthermore, the results indicate a lower bioavailability of IGF-I in OC. In conclusion, synthetic female sex hormones administered as OC had an inhibiting effect on collagen synthesis in tendon, bone, and muscle connective tissue, which may be related to a lower bioavailability of IGF-I.

Direct regulation of ZAP-70 by SHP-1 in T cell antigen receptor signaling.

The threshold at which antigen triggers lymphocyte activation is set by the enzymes that regulate tyrosine phosphorylation. Upon T cell activation, the protein tyrosine phosphatase SHP-1 was found to bind to the protein tyrosine kinase ZAP-70. This interaction resulted in an increase in SHP-1 phosphatase activity and a decrease in ZAP-70 kinase activity. Expression of a dominant negative mutant of SHP-1 in T cells increased the sensitivity of the antigen receptor. Thus, SHP-1 functions as a negative regulator of the T cell antigen receptor and in setting the threshold of activation.

CD8+ T-cell clones deficient in the expression of the CD45 protein tyrosine phosphatase have impaired responses to T-cell receptor stimuli.

CD45 is a high-molecular-weight transmembrane protein tyrosine phosphatase expressed only by nucleated cells of hematopoietic origin. To examine function, mouse CD8+ cytolytic T-cell clones were derived that had a specific defect in the expression of CD45. Northern (RNA) blot analysis indicates that the CD45 deficiency is due to either a transcriptional defect or mRNA instability. The CD45-deficient cells were greatly diminished in their ability to respond to antigen. All functional parameters of T-cell receptor signalling analyzed (cytolysis of targets, proliferation, and cytokine production) were markedly diminished. A CD45+ revertant was isolated, and the ability to respond to antigen was restored. These results support a central and immediate role for this transmembrane protein tyrosine phosphatase in T-cell receptor signalling.

Detection of 549 new HLA alleles in potential stem cell donors from the United States, Poland and Germany.

We characterized 549 new human leukocyte antigen (HLA) class I and class II alleles found in newly registered stem cell donors as a result of high-throughput HLA typing. New alleles include 101 HLA-A, 132 HLA-B, 105 HLA-C, 2 HLA-DRB1, 89 HLA-DQB1 and 120 HLA-DPB1 alleles. Mainly, new alleles comprised single nucleotide variations when compared with homologous sequences. We identified nonsynonymous nucleotide mutations in 70.7% of all new alleles, synonymous variations in 26.4% and nonsense substitutions in 2.9% (null alleles). Some new alleles (55, 10.0%) were found multiple times, HLA-DPB1 alleles being the most frequent among these. Furthermore, as several new alleles were identified in individuals from ethnic minority groups, the relevance of recruiting donors belonging to such groups and the importance of ethnicity data collection in donor centers and registries is highlighted.

A comparative reference study for the validation of HLA-matching algorithms in the search for allogeneic hematopoietic stem cell donors and cord blood units.

The accuracy of human leukocyte antigen (HLA)-matching algorithms is a prerequisite for the correct and efficient identification of optimal unrelated donors for patients requiring hematopoietic stem cell transplantation. The goal of this World Marrow Donor Association study was to validate established matching algorithms from different international donor registries by challenging them with simulated input data and subsequently comparing the output. This experiment addressed three specific aspects of HLA matching using different data sets for tasks of increasing complexity. The first two tasks targeted the traditional matching approach identifying discrepancies between patient and donor HLA genotypes by counting antigen and allele differences. Contemporary matching procedures predicting the probability for HLA identity using haplotype frequencies were addressed by the third task. In each task, the identified disparities between the results of the participating computer programs were analyzed, classified and quantified. This study led to a deep understanding of the algorithms participating and finally produced virtually identical results. The unresolved discrepancies total to less than 1%, 4% and 2% for the three tasks and are mostly because of individual decisions in the design of the programs. Based on these findings, reference results for the three input data sets were compiled that can be used to validate future matching algorithms and thus improve the quality of the global donor search process.

Assessing the dimensions of pain: a multitrait-multimethod evaluation of seven measures.

A multitrait-multimethod design was used to examine the convergent and discriminant validity of seven pain measures from three widely used self-report instruments designed to assess the sensory, affective and intensity dimensions of pain. The instruments were the McGill Pain Questionnaire, the Pain Perception Profile and Numerical Ratings. Three distinct factor models, each corresponding to a different hypothesis about how these pain measures are related, were tested using confirmatory factor analysis in a sample of 419 headache sufferers. A three-factor model, postulating three correlated factors defined by the three assessment instruments best explained the correlations between the pain measures. Measures of sensory, affective and intensity dimensions from the three instruments failed to exhibit convergent or discriminant validity. Rather, instrument variance obscured the pain qualities the three pain instruments were designed to assess. These findings suggest that greater attention needs to be paid to how formal characteristics of pain assessment instruments influence patients' descriptions of their pain.

A comparison of pharmacological (amitriptyline HCL) and nonpharmacological (cognitive-behavioral) therapies for chronic tension headaches.

Forty-one recurrent tension headache sufferers were randomly assigned to either cognitive-behavioral therapy (administered in a primarily home-based treatment protocol) or to amitriptyline therapy (with dosage individualized at 25, 50, or 75 mg/day). Cognitive-behavioral therapy and amitriptyline each yielded clinically significant improvements in headache activity, both when improvement was assessed with patient daily recordings (56% and 27% reduction in headache index, respectively), and when improvement was assessed with neurologist ratings of clinical improvement (94% and 69% of patients rated at least moderately improved, respectively). In instances where differences in treatment effectiveness were observed (headache index, somatic complaints, perceptions of control of headache activity), cognitive-behavioral therapy yielded somewhat more positive outcomes than did amitriptyline. Neither treatment, however, eliminated headache problems.

An update to the HLA Nomenclature Guidelines of the World Marrow Donor Association, 2012.

For more than two decades, international cooperation and information technology have been playing key roles in the identification of suitable unrelated donors and cord blood units for hematopoietic SCT. To ensure consistent coding and interpretation of HLA data among the linked computer systems, the World Marrow Donor Association has standardized the extensions of the World Health Organization (WHO) Nomenclature for factors of the HLA system applied in practice. The first version of this report published in 2007 has become the reference for the technical validation of HLA information on donors and patients in the context of search and matching and is used by registries of volunteer unrelated hematopoietic stem cell donors and umbilical cord blood banks throughout the world. The present update became necessary after the major revision of the WHO HLA nomenclature in April 2010. It now covers issues arising when alleles are withdrawn or renamed because of the continuous updating of the WHO HLA nomenclature. In addition, formal validation and interpretation rules for the so-called 'multiple allele codes' have been added.

Effects of transdermal estrogen on collagen turnover at rest and in response to exercise in postmenopausal women.

Menopause is associated with loss of collagen content in the skin and tendon as well as accumulation of noncontractile tissue in skeletal muscle. The relative role of hormones and physical activity on these changes is not known. Accordingly, in a randomized, controlled, crossover study we investigated effects of transdermal estrogen replacement therapy (ERT) on type I collagen synthesis in tendon and skeletal muscle in 11 postmenopausal women. Patches with estrogen (Evorel) were placed on the skin above the patellar tendons and compared with no patch (control period). On day 2 all subjects performed one-legged exercise, and thereafter the exercised leg (EX leg) was compared with the nonexercised leg (Rest leg). Microdialysis catheters were placed in front of the patellar tendons and in the vastus lateralis muscle of both legs at days 3 and 5. The collected dialysate was analyzed for procollagen type I NH(2)-terminal propeptide (PINP), insulin-like growth factor I (IGF-I), and interleukin-6 (IL-6). Neither loading (Rest leg vs. EX leg) nor treatment (control vs. ERT) influenced peritendinous PINP, whereas combined exercise and ERT enhanced muscle PINP after 72 h (interaction between loading and treatment P = 0.008). In neither skeletal muscle nor peritendinous fluid were IGF-I and IL-6 influenced by treatment or exercise. In conclusion, ERT was associated with enhanced synthesis of type I collagen in the skeletal muscle in response to acute exercise. In perspective, this indicates that the availability of estrogen in postmenopausal women is important for repair of muscle damage or remodeling of the connective tissue within the skeletal muscle after exercise.

Evidence that the leukocyte-common antigen is required for antigen-induced T lymphocyte proliferation.

The leukocyte-common antigen (L-CA) is a family of large molecular weight glycoproteins uniquely expressed on the surface of all nucleated cells of hematopoietic origin. The glycoprotein consists of a heavily glycosylated exterior domain, a single membrane spanning region, and a large cytoplasmic domain that contains tyrosine phosphatase activity. To investigate the function of this family, we generated T cell clones that lacked L-CA (L-CA-). The expression of the alpha beta T cell receptor, CD3, CD4, IL-2 receptor (p55), LFA-1, Thy-1, and Pgp-1 (CD44) was normal. The L-CA- T cell clones failed to proliferate in response to antigen or cross-linked CD3; however, they could still proliferate in response to IL-2. An L-CA+ revertant was obtained and the ability to proliferate in response to antigen and cross-linked CD3 was restored. These data indicate that L-CA is required for T cells to enter into cell cycle in response to antigen.