Neutrophil-derived catecholamines mediate negative stress effects on bone.

Mental traumatization is associated with long-bone growth retardation, osteoporosis and increased fracture risk. We revealed earlier that mental trauma disturbs cartilage-to-bone transition during bone growth and repair in mice. Trauma increased tyrosine hydroxylase-expressing neutrophils in bone marrow and fracture callus. Here we show that tyrosine hydroxylase expression in the fracture hematoma of patients correlates positively with acknowledged stress, depression, and pain scores as well as individual ratings of healing-impairment and pain-perception post-fracture. Moreover, mice lacking tyrosine hydroxylase in myeloid cells are protected from chronic psychosocial stress-induced disturbance of bone growth and healing. Chondrocyte-specific ß2-adrenoceptor-deficient mice are also protected from stress-induced bone growth retardation. In summary, our preclinical data identify locally secreted catecholamines in concert with ß2-adrenoceptor signalling in chondrocytes as mediators of negative stress effects on bone growth and repair. Given our clinical data, these mechanistic insights seem to be of strong translational relevance.

Myeloid cell-derived catecholamines influence bone turnover and regeneration in mice.

Catecholamine signaling is known to influence bone tissue as reuptake of norepinephrine released from sympathetic nerves into bone cells declines with age leading to osteoporosis. Further, ß-adrenoceptor-blockers like propranolol provoke osteoprotective effects in osteoporotic patients. However, besides systemic adrenal and sympathetic catecholamine production, it is also known that myeloid cells can synthesize catecholamines, especially under inflammatory conditions. To investigate the effects of catecholamines produced by CD11b+ myeloid cells on bone turnover and regeneration, a mouse line with specific knockout of tyrosine hydroxylase, the rate-limiting enzyme of catecholamine synthesis, in CD11b+ myeloid cells (THflox/flox/CD11b-Cre+, referred to as THCD11b-Cre) was generated. For bone phenotyping, male mice were sacrificed at eight and twelve weeks of age and harvested bones were subjected to bone length measurement, micro-computed tomography, fluorescence-activated cell sorting of the bone marrow, gene expression analysis, histology and immunohistochemistry. Support for an age-dependent influence of myeloid cell-derived catecholamines on bone homeostasis is provided by the fact that twelve-week-old, but not eight-week-old THCD11b-Cre mice, developed an osteopenic phenotype and showed increased numbers of neutrophils and T lymphocytes in the bone marrow, while CCL2, IL-6, IL-4 and IL-10 mRNA expression was reduced in sorted myeloid bone marrow cells. To investigate the influence of myeloid cell-derived catecholamines on fracture healing, mice received a diaphyseal femur osteotomy. Three days post-fracture, immunohistochemistry revealed an increased number of macrophages, neutrophils and cytotoxic T lymphocytes in the fracture hematoma of THCD11b-Cre mice. Micro-computed tomography on day 21 showed a decreased tissue mineral density, a reduced bone volume and less trabeculae in the fracture callus indicating delayed fracture healing, probably due to the increased presence of inflammatory cells in THCD11b-Cre mice. This indicates a crucial role of myeloid cell-derived catecholamines in immune cell-bone cell crosstalk and during fracture healing.

Teachers' Perceptions of Word Callers and Related Literacy Concepts.

The purpose of the study was to investigate teachers' perceptions of word callers as they relate to the concepts of reading fluency and reading comprehension. To this end, second grade students (N = 408) completed a series of reading fluency and reading comprehension assessments, and their teachers (N = 31) completed word caller nominations and a questionnaire regarding their concepts surrounding these issues. Our findings suggested that teachers often over nominated children as word callers. Further, questionnaire data indicated a great deal of ambiguity and inconsistency exists regarding teachers' understanding and use of the term word caller. By contrast, teachers seemed to possess a veridical understanding of the related terms reading fluency and reading comprehension.

Insights into Fluency Instruction: Short- and Long-term Effects of Two Reading Programs.

The purpose of the study was to examine short- and long-term effects of two instructional approaches designed to improve the reading fluency of second grade children: Fluency-Oriented Reading Instruction (or FORI; Stahl & Heubach, 2005) and a wide reading approach (Kuhn et al., 2006). By the end of second grade, children in the wide reading classrooms showed better fluency and self-concept compared to children in control classrooms. Classroom observations indicated children in FORI classrooms were more likely to be off-task than controls. However, by the end of third grade, children in both programs displayed better comprehension. We conclude that extensive and long-term focus on the oral reading of complex texts using practices that scaffold reading in second grade is beneficial for the long-term development of reading comprehension skills.

Myth and Reality of the Word Caller: The Relation Between Teacher Nominations and Prevalence Among Elementary School Children.

The purpose of the study was to investigate (a) the prevalence of word callers in elementary school, (b) the accuracy of teachers' word caller nominations, and (c) teachers' conceptualization of reading fluency and reading comprehension. To this end, 2 cross-sectional studies of second- and third- (N = 868) and of third- and fifth-grade (N = 202) children were conducted. Our findings suggest that word callers occur infrequently in the primary grades but that they are more prevalent in late elementary school. Regardless of grade level, teachers often overnominated children as word callers. Furthermore, a great deal of ambiguity and inconsistency seems to exist regarding teachers' understanding and use of the term. These findings suggest that the term should be used relatively rarely and that reading educators should be cautious about their identification of word callers in early elementary school.

The influence of reading unit size on the development of Stroop interference in early word decoding.

The purpose of the experiments was to determine the automatic use of large or small word reading units in young readers in the absence of word decoding strategies. Picture-word Stroop interference was examined from four types of conflicting labels: (a) words containing both highly predictable grapheme-phoneme correspondence (GPC) units and highly consistent rime units (henceforth, Hi-GPC + Hi-Rime); (b) words with highly predictable GPC units and less consistent rime units (Hi-GPC + Lo-Rime); (c) words with low predictability GPC units and highly consistent rime units (Low GPC + High Rime); (d) nonwords that contained both highly predictable GPC and highly consistent rime units. Naming time for pictures containing these labels was compared against that for pictures with random letter strings or no labels. In Experiment 1, Stroop interference was examined in first, second, and third grade children to determine whether there was developmental change in the presence of rime or GPC interference. In Experiment 2, Stroop interference was examined as a function of relative reading skill in first grade children. In Experiment 3, Stroop interference in adults was compared to the use of rime or GPC pronunciation strategies for nonword reading. In all experiments, Stroop interference in picture naming was longer for pictures with highly predictable GPC unit labels than less predictable GPC unit labels. However, in Experiment 3, even though adults showed interference from predictable GPC units in the Stroop task, they always preferred rime pronunciation for ambiguous non-words in the nonword reading task. It is argued that the current experiments provide evidence for a flexible units model.

Teaching Children to Become Fluent and Automatic Readers.

The purpose of the study was to examine the effects of two instructional approaches designed to improve the reading fluency of 2nd-grade children. The first approach was based on Stahl and Heubach's (2005) fluency-oriented reading instruction (FORI) and involved the scaffolded, repeated reading of grade-level texts over the course of each week. The second was a wide-reading approach that also involved scaffolded instruction. hut that incorporated the reading of 3 different grade-level texts each week and provicled significantly less opportunity for repetition. By the end of the school year. FORI and wide-reading approaches showed similar benefits for standardized measures of word reading efficiency and reading comprehension skills compared to control approachcs. although the benefits of the wide-reading approach emerged earlier and included oral text reading fluency skill. Thus, we conclude that fluency instruction that emphasizes extensive oral reading of grade-level text using scaffolded approaches is effective for promoting reading development in young learners.

Becoming a fluent and automatic reader in the early elementary school years.

The goals of this study were to (a) develop an empirically based model regarding the development of fluent and automatic reading in the early elementary school years and (b) determine whether fluent text-reading skills provided benefits for reading comprehension beyond those accounted for by fluent word decoding. First-, second-, and third-grade children completed a series of reading tasks targeting word and nonword processing, text reading, spelling knowledge, autonomous reading, and reading comprehension. Structural equation modeling was carried out to evaluate how these skills operated together to produce fluent text reading and good comprehension. Evidence supported a simple reading fluency model for the early elementary school years suggesting that fluent word and text reading operate together with autonomous reading to produce good comprehension.

Becoming a Fluent Reader: Reading Skill and Prosodic Features in the Oral Reading of Young Readers.

Prosodic reading, or reading with expression, is considered one of the hallmarks of fluent reading. The major purpose of the study was to learn how reading prosody is related to decoding and reading comprehension skills. Suprasegmental features of oral reading were measured in 2nd- and 3rd-grade children (N = 123) and 24 adults. Reading comprehension and word decoding skills were assessed. Children with faster decoding speed made shorter and less variable intersentential pauses, shorter intrasentential pauses, larger sentence-final fundamental frequency (F(0)) declinations, and better matched the adult prosodic F(0) profile. Two structural equation models found evidence of a relationship between decoding speed and reading prosody as well as decoding speed and comprehension. There was only minimal evidence that prosodic reading was an important mediator of reading comprehension skill.