Extrathyroidal expression of TSH receptor

The TSH receptor expressed on the cell surface of thyroid follicular cells plays a pivotal role in the regulation of thyroid status and growth of the thyroid gland. In recent years it has become evident that the TSH receptor is also expressed widely in a variety of extrathyroidal tissues including: anterior pituitary; hypothalamus; ovary; testis; skin; kidney; immune system; bone marrow and peripheral blood cells; white and brown adipose tissue; orbital preadipocyte fibroblasts and bone. A large body of evidence is emerging to describe the functional roles of the TSH receptor at these various sites but their physiological importance in many cases remains a subject of controversy and much interest. Current understanding of the actions of the TSH receptor in extrathyroidal tissues and their possible physiological implications is discussed.

Thyroid hormones and bone development

Thyroid hormones are critical determinants of postnatal skeletal development. Thyroid hormone deficiency or excess in children results in severe abnormalities of linear growth and bone maturation. These clinical observations have been recapitulated in mutant mice and these models have facilitated studies of the mechanisms of thyroid hormone action in the developing skeleton. In this review, we consider in detail the direct and indirect effects of thyroid hormone on bone and the molecular mechanisms involved.

Hybridization of leucyl-transfer ribonucleic Acid isoacceptors from green leaves with nuclear and chloroplast deoxyribonucleic Acid

Chromatographically distinct isoacceptors of leucyl-tRNA from mature bean leaves were all observed to hybridize with bean chloroplast and nuclear DNA in a ratio similar to that exhibited by the unfractionated leucyl-tRNA. Under the same hybridization conditions, maize tRNA failed to form a stable hybrid with bean DNA, and levels of hybridization between bean-leaf leucyl-tRNA and nuclear or chloroplast DNAs from tobacco and maize were relatively small.

Benzofuran derivatives and the thyroid

Amiodarone and dronedarone are two clinically important benzofuran derivatives. Amiodarone has been used widely for treating resistant tachyarrhythmias in the past three decades. However amiodarone and its main metabolically active metabolite desethylamiodarone can adversely affect many organs, including the thyroid gland. Amiodarone-induced thyroid disorders are common and often present as a management challenge for endocrinologists. The pathogenesis of amiodarone-induced thyroid dysfunction is complex but the inherent effects of the drug itself as well as its high iodine content appear to play a central role. The non-iodinated dronedarone also exhibits anti-arrhythmic properties but appears to be less toxic to the thyroid. This review describes the biochemistry of benzofuran derivatives, including their pharmacology and the physiology necessary for understanding the cellular mechanisms involved in their actions. The known effects of these compounds on thyroid action are described. Recommendations for management of amiodarone-induced hypothyroidism and thyrotoxicosis are suggested. Dronedarone appears to be an alternative but less-effective anti-arrhythmic agent and it does not have adverse effects on thyroid function. It may have a future role as an alternative agent in patients being considered for amiodarone therapy especially those at high risk of developing thyroid dysfunction but not in severe heart failure.

Neurodevelopmental and neurophysiological actions of thyroid hormone

For over 100 years, thyroid hormones have been known to be essential for neonatal neurodevelopment but whether they are required by the foetal brain remains a matter of controversy. For decades, the prevailing view was that thyroid hormones are not necessary until after birth because circulating levels in the foetus are very low and the placenta forms an efficient barrier to their transfer from the mother. Clinical observations of good neurological outcome following early treatment of congenital hypothyroidism were used to support the view that thyroid hormones are not required early in neurodevelopment. Nevertheless, the issue remained contentious because of findings that the severity of foetal neurological deficit due to maternal iodine deficiency correlated with the degree of maternal thyroxine (T4) deficiency. Furthermore, neurological damage in these cases could be prevented by correction of maternal T4 deficiency before mid-gestation. This observation led to the opposing view, supported by epidemiological studies of neurological cretinism, that maternal thyroid hormones are important and necessary for early foetal neurodevelopment. It is now clear that thyroid hormones are essential for both foetal and post-natal neurodevelopment and for the regulation of neuropsychological function in children and adults. In recent years, this controversial subject has progressed very rapidly following remarkable progress in understanding of the molecular mechanisms of thyroid hormone action. This article reviews the contributions of molecular biology and genetics to our new understanding of the physiological effects of thyroid hormones on neurodevelopment and in the adult brain.

Long durations of immobilization in the rat result in enhanced mechanical properties of the healing supraspinatus tendon insertion site

Rotator cuff tears frequently occur and can lead to pain and decreased shoulder function. Repair of the torn tendon back to bone is often successful in relieving pain, but failure of the repair commonly occurs. Post-operative activity level is an important treatment component that has received minimal attention for the shoulder, but may have the potential to enhance tendon to bone healing. The objective of this study was to investigate the effect of short and long durations of various activity levels on the healing supraspinatus tendon to bone insertion site. Rotator cuff tears were surgically created in Sprague-Dawley rats by detaching the supraspinatus tendon from its insertion on the humerus and these tears were immediately repaired back to the insertion site. The post-operative activity level was controlled through shoulder immobilization (IM), cage activity (CA), or moderate exercise (EX) for durations of 4 or 16 weeks. The healing tissue was evaluated utilizing biomechanical testing and a quantitative polarized light microscopy method. We found that activity level had no effect on the elastic properties (stiffness, modulus) of the insertion site at four weeks post injury and repair, and a decreased activity level had a positive effect on these properties at 16 weeks (IM>CA=EX). Furthermore, a decreased activity level had the greatest positive effect on these properties over time (IM>CA=EX). The angular deviation of the collagen, a measure of disorganization, was decreased with a decrease in activity level at 4 weeks (IM<CA=EX), but was similar between groups at 16 weeks (IM=CA=EX). It appears from this study that decreasing the activity level by immobilizing the shoulder improves tendon to bone healing, which progresses by first increasing the organization of the collagen and then increasing the mechanical properties. Future studies in this area will investigate the effect of passive motion and remobilization on both tendon to bone healing and shoulder function.

Detection of central respiratory events using pulse transit time in infants

The prevalence of sudden infant death syndrome (SIDS) has been well studied and central sleep apnea is deemed as one of the possible causes. Current gold standard for its diagnosis is nocturnal polysomnography (PSG). However, this procedure is complex and generally needs to be performed in a sleep laboratory. Pulse transit time (PTT) shows its potential to indicate abrupt blood pressure (BP) changes during the occurrences of upper airway obstruction. The main objective of this study was to assess the capability of PTT to differentiate central respiratory events from tidal breathing in infants. This study involved 5 infants (4 male) with mean age of 7.8 months. 50 valid central respiratory events were randomly selected. These events were free from motion artifacts and pre-scored in the corresponding PSG studies by two blinded observers. PTT measurements from these events were then evaluated against the PSG scorings. Using a two-tailed F-test for variance, it was observed that central events differed from tidal breathing in a significant manner (p<0.05). Furthermore, PTT has showed its sensitivity to monitor marginal BP fluctuations during tidal breathing. Hence, the results herein suggest that PTT can be a valuable non-invasive technique to monitor central apneic events in sleeping infants.

Use of regression equation of peripheral pulse timing characteristics to predict hypertension in children

Studies have shown that an increase in arterial stiffening can indicate the presence of cardiovascular diseases like hypertension. Current gold standard in clinical practice is by measuring the blood pressure of patients using a mercury sphygmomanometer. However, the nature of this technique is not suitable for prolonged monitoring. It has been established that pulse wave velocity is a direct measure of arterial stiffening. However, its usefulness is hampered by the absence of techniques to estimate it non-invasively. Pulse transit time (PTT) is a simple and non-intrusive method derived from pulse wave velocity. It has shown its capability in childhood respiratory sleep studies. Recently, regression equations that can predict PTT values for healthy Caucasian children were formulated. However, its usefulness to identify hypertensive children based on mean PTT values has not been investigated. This was a continual study where 3 more Caucasian male children with known clinical hypertension were recruited. Results indicated that the PTT predictive equations are able to identify hypertensive children from their normal counterparts in a significant manner (p<0.05). Hence, PTT can be a useful diagnostic tool in identifying hypertension in children and shows potential to be a non-invasive continual monitor for arterial stiffening.

Relations between Physiologic Parameters and Pulse Transit Time during Loaded Breathing

Pulse transit time (PTT) is a non-invasive measure, defined as time taken for the pulse pressure waves to travel from the R-wave of electrocardiogram to a selected peripheral site. Baseline PTT value is known to be influenced by physiologic variables like heart rate (HR), blood pressure (BP) and arterial compliance (AC). However, few quantitative data are available describing the factors which can influence PTT measurements in a child during breathing. The aim of this study was to investigate the effects of changes in breathing efforts on PTT baseline and fluctuations. Two different inspiratory resistive loading (IRL) devices were used to simulate loaded breathing in order to induce these effects. It is known that HR can influence the normative PTT value however the effect of HR variability (HRV) is not well-studied. Two groups of 3 healthy children (&#8804;12years) were recruited; one group with insignificant (p>0.05) HR changes during all test activities. Results showed that HRV is not the sole contributor to PTT variations and suggest that changes in other physiologic parameters are also equally important. Hence, monitoring PTT measurement can be indicative of these associated changes during tidal or increased breathing efforts in healthy children.

Thyroid hormone regulates heparan sulfate proteoglycan expression in the growth plate

Thyroid hormone is essential for normal skeletal development. Hypothyroidism is associated with growth arrest, failure of chondrocyte differentiation, and abnormal matrix synthesis. Thyroid hormone modulates the Indian hedgehog/PTHrP feedback loop and regulates fibroblast growth factor (FGF)/FGF receptor signaling. Because heparan sulfate (HS) proteoglycans (Prgs) (HSPGs) are absolutely required by these signaling pathways, we have investigated whether thyroid status affects HSPG expression within the growth plate. Tibial growth plate sections were obtained from 12-wk-old rats rendered euthyroid, thyrotoxic, or hypothyroid at 6 wk of age, 14-d-old congenitally hypothyroid Pax8-null mice, and TRalpha/TRbeta double-null mice lacking all thyroid hormone receptors. HS and chondroitin sulfate Prg expression was determined by immunohistochemistry using three monoclonal antibodies. There was increased HS staining in growth plates from hypothyroid animals predominantly within the extracellular matrix of reserve and proliferative zones. Cellular HS staining was also increased particularly in prehypertrophic chondrocytes. T3 regulation of HSPG core protein and HS synthetic and modification enzyme expression was studied in ATDC5 cells using semiquantitative RT-PCR. Thyroid hormone negatively regulated expression of the core protein Gpc6, the polymerase Ext1, and the modification enzyme Hs6st2. These studies demonstrate that the expression and distribution of growth plate Prgs are regulated by thyroid hormone, and the regulation of HSPG expression provides an important additional link between FGF and Indian hedgehog signaling and T3. These novel observations suggest that the cartilage matrix and especially HSPGs are critical mediators of the skeletal response to thyroid hormone.

Effects of thyroid status on bone metabolism: a primary role for thyroid stimulating hormone or thyroid hormone?

Thyroid hormones are essential for normal skeletal growth and the maintenance of bone mass in adulthood, although their mechanism of action in bone is poorly understood. Hypothyroidism causes impaired bone formation and growth retardation whereas thyrotoxicosis results in accelerated growth, advanced bone age and decreased bone mass. Adults with thyrotoxicosis or a suppressed thyroid stimulating hormone (TSH) from any cause have an increased risk of osteoporotic fracture. Conventionally, bone loss in thyrotoxicosis has been regarded as a direct consequence of thyroid hormone excess acting locally on bone. Recently, however, it has been proposed that TSH may be a direct negative regulator of bone turnover acting via the TSH receptor on both osteoblasts and osteoclasts. Thus, TSH deficiency could be partly responsible for the skeletal loss seen in thyrotoxicosis. Here we provide an overview of the molecular actions of thyroid hormone in bone and discuss in detail the current evidence relating to a possible role for TSH in bone metabolism.

A clinically meaningful difference was generated for a performance measure of recovery from hip fracture

BACKGROUND AND OBJECTIVE

The Lower Extremity Gain Scale (LEGS) is a performance measure of tasks that are often impaired in hip fracture patients. This study was designed to determine a clinically meaningful difference in LEGS.

METHODS

The population was 139 female patients (age >65 years) admitted to Baltimore hospitals. Recovery levels were estimated by fitting trajectory curves for the cohort for the 12 months post fracture. The clinically meaningful difference was evaluated using an anchor-based approach, examining the relationship between the LEGS recovery level and age. A second, distribution-based method used an effect size of .20.

RESULTS

According to our model, a difference of 5 years in age corresponded to a difference of 1.6-3.6 points in LEGS scores. The standard deviation for LEGS at 12 months was 8.0; thus, Cohen's effect size of 0.2 would equate to a difference of 1.6 points.

CONCLUSION

This suggests that a clinically meaningful difference in the LEGS scores for a population in this age range would be 2-3 points.

Motion artefact reduction of the photoplethysmographic signal in pulse transit time measurement

Motion artefact is a common occurrence that contaminates photoplethysmographic (PPG) measurements. To extract timing information from signals during artefact is challenging. PPG signal is very sensitive to artefacts and can be used in applications like, pulse transit time (PTT) as part of the polysomnographic studies. A correlation cancellation or signal processing approach is implemented with the adaptive cancelling filter concept and a triaxial accelerometry. PPG signals obtained from a Masimo (Reference) pulse oximeter is used as reference to compare with the reconstructed PPG signals. Different hands are used for each PPG source, one stationary while the other involves typical movements during sleep. A second Masimo pulse oximeter is used to register intensity of timing errors on commercial PPG signals. 108 PTT measurements are recorded in three different movements with PTT estimates from unprocessed PPG signals showing 35.51+/-27.42%, Masimo 50.02+/-29.40% and reconstructed 4.32+/-3.59% difference against those from the Reference PPG. The triaxial accelerometry can be used to detect the presence of artefact on PPG signals. This is useful in PTT measurements when signal contaminated with artefacts are required for further analysis, especially after and during arousals in sleep. The suggested filtering model can then reconstruct these corrupted PPG signals.

Analysis of thyroid hormone responsive gene expression in osteoblastic cells

Thyroid hormones regulate gene expression to influence the development and metabolism of many tissues including bone. The identification of genes that are regulated by thyroid hormones during skeletal development requires sensitive and quantitative techniques that are not limited by small amounts of available tissue and RNA. We have compared the efficiencies of differential display and poly A PCR subtraction hybridisation methods for the detection of thyroid hormone responsive genes expressed in osteoblastic cells. The utility of each technique was evaluated with respect to its sensitivity, specificity, cost and ability to identify novel genes. Subtraction hybridisation was rapid and more efficient in all categories. Poly A PCR facilitates quantitative and representative global amplification of cDNAs from low concentrations of RNA extracted from small tissue samples. The method, in combination with microarray analyses, may prove useful as an additional, complementary strategy to subtraction hybridisation for the analysis of differential gene expression in tissues where sample size is limiting.

Tendon to bone healing: differences in biomechanical, structural, and compositional properties due to a range of activity levels

Little knowledge exists about the healing process of the tendon to bone insertion, and hence little can be done to improve tissue healing. The goal of this study is to describe the healing of the supraspinatus tendon to its bony insertion under a variety of loading conditions. Tendons were surgically detached and repaired in rats. Rat shoulders were then immobilized, allowed cage activity, or exercised. Shoulders that were immobilized demonstrated superior structural (significantly higher collagen orientation), compositional (expression of extracellular matrix genes similar to the uninjured insertion), and quasilinear viscoelastic properties (A = 0.30 +/- 0.10 MPa vs. 0.16 +/- 0.08 MPa, B = 17.4 +/- 2.9 vs. 15.1 +/- 0.9, and tau 2 = 344 +/- 161 s vs. 233 +/- 40 s) compared to those that were exercised, contrary to expectations. With this knowledge of the healing response, treatment modalities for rotator cuff tears can be developed.

Insight into the physiological actions of thyroid hormone receptors from genetically modified mice

Thyroid hormones exert a range of developmental and physiological actions in all vertebrates. Serum concentrations of L-thyroxine (T4) and 3,5,3 -L-triiodothyronine (T3) are maintained by a negative feedback loop involving T3-inhibition of hypothalamic thyrotrophin releasing hormone (TRH) and pituitary thyroid stimulating hormone (TSH) secretion, and by tissue specific and hormone-regulated expression of the three iodothyronine deiodinase enzymes that activate or metabolise thyroid hormones. T3 actions are mediated by two T3-receptors, TRalpha and TRbeta, which act as hormone-inducible transcription factors. The TRalpha (NR1A1) and TRbeta (NR1A2) genes encode mRNAs that are alternatively spliced to generate 9 mRNA isoforms (TRalpha1, alpha2, alpha3, Deltaalpha1, Deltaalpha2, beta1, beta2, beta3 and Deltabeta3), of which four (TRalpha1, alpha2, beta1 and beta2) are known to be expressed at the protein level in vivo. The numerous TR mRNAs are expressed widely in tissue- and developmental stage-specific patterns, although it is important to note that levels of mRNA expression may not correlate with receptor protein concentrations in individual tissues. The TRalpha2, alpha3, Deltaalpha1 and Deltaalpha2 transcripts encode proteins that fail to bind T3 in vitro. These non-binding isoforms, in addition to TRDeltabeta3 which does bind hormone, may act as dominant negative antagonists of the true T3-binding receptors in vitro, but their physiological functions and those of the TRbeta3 isoform have not been determined. In order to obtain a new understanding of the complexities of T3 action in vivo and the role of TRs during development, many mouse models of disrupted or augmented thyroid hormone signalling have been generated. The aim of this review is to provide a picture of the physiological actions of thyroid hormones by considering the phenotypes of these genetically modified mice.

Dexamethasone inhibits and thyroid hormone promotes differentiation of mouse chondrogenic ATDC5 cells

The effects of glucocorticoid (GC) excess, thyrotoxicosis, and hypothyroidism on linear growth indicate that growth plate chondrocytes are exquisitely sensitive to GC and thyroid hormone (T(3)). Murine ATDC5 cells undergo chondrogenesis in vitro and were used to evaluate the effects of dexamethasone (Dex) and T(3) on cell proliferation and differentiation. Immature and differentiated ATDC5 cells expressed glucocorticoid and T(3)-receptor mRNAs. Cells proliferated and organized into cartilage-like nodules after 7 days. Chondrocyte maturation progressed over 9-40 days, with increasing alkaline phosphatase (ALP) activity, secretion of an Alcian blue-positive matrix, and mineralization of cartilage-like nodules. Dex reduced cell number over the 40 day period, causing inhibition of ALP activity and matrix production with failure of mineralization. Following withdrawal of Dex, chondrocytes proliferated and re-entered the differentiation and mineralization program, indicating that GC inhibition of chondrogenesis is reversible. In contrast, T(3) reduced cell proliferation, but induced ALP activity and increased matrix secretion earlier than in control cultures. Thus, GCs and T(3) regulate growth plate chondrocyte differentiation by distinct mechanisms. GCs arrest cell proliferation, differentiation, and cartilage mineralization and maintain chondrocyte precursors in a state of quiescence with the capacity to re-enter chondrogenesis. T(3) inhibits cell proliferation but accelerates differentiation to stimulate chondrogenesis.

The localized expression of extracellular matrix components in healing tendon insertion sites: an in situ hybridization study

The localized expression of a number of extracellular matrix genes was evaluated over time in a novel rat rotator cuff injury model. The supraspinatus tendons of rats were severed at the bony insertion and repaired surgically. The healing response was evaluated at 1, 2, 4, and 8 weeks post-injury using histologic and in situ hybridization techniques. Expression patterns of collagens (I, II, III, IX, X, XII), proteoglycans (decorin, aggrecan, versican, biglycan, fibromodulin), and other extracellular matrix proteins (elastin, osteocalcin, alkaline phosphatase) were evaluated at the healing tendon to bone insertion site. Histologic results indicate a poor healing response to the injury, with only partial recreation of the insertion site by 8 weeks. In situ hybridization results indicate a specific pattern of genes expressed in each zone of the insertion site (i.e., tendon, fibrocartilage, mineralized cartilage, bone). Overall, expression of collagen types I and XII, aggrecan, and biglycan was increased, while expression of collagen type X and decorin was decreased. Expression of collagen type I, collagen type XII, and biglycan decreased over time, but remained above normal at 8 weeks. Results indicate that the rat supraspinatus tendon is ineffective in recreating the original insertion site, even at 8 weeks post-injury, in the absence of biological or biomechanical enhancements.

Glucocorticoids, thyroid hormone and growth hormone interactions: implications for the growth plate

Linear growth occurs during childhood and results from endochondral ossification in the growth plate. Prepubertal growth is primarily regulated by growth hormone (GH) and insulin-like growth factor (IGF)-I, with important contributions from glucocorticoids (GC) and thyroid hormone (T(3)). The somatomedin hypothesis proposed that GH stimulates hepatic IGF-I production, which then regulates growth via IGF-I receptor expressing chondrocytes in an endocrine fashion. Recent studies indicate that locally acting IGF-I is a key determinant of endochondral ossification and that GH, GC and T(3) regulate expression of IGF-I and its receptor in the growth plate directly. Analysis of hormone imbalance during childhood and studies of genetically modified mice provide support for an important GH and IGF-I autocrine/paracrine pathway and for direct effects of GC and T(3) during endochondral ossification. Thus, the epiphyseal growth plate is a key site for convergent hormone action that mediates the control of linear growth.

Complications of thermal capsulorrhaphy of the shoulder

BACKGROUND

The purpose of this study was to evaluate the rate of recurrence and the prevalence of complications related to the use of thermal energy for the treatment of glenohumeral instability.

METHODS

A survey was conducted of all members of the American Shoulder and Elbow Surgeons, the Arthroscopy Association of North America, and the American Orthopaedic Society for Sports Medicine. The survey focused on the rate of recurrence, the number of axillary nerve injuries, and the prevalence of capsular insufficiency seen in revision surgery after thermal capsulorrhaphy of the shoulder.

RESULTS

Three hundred and seventy-nine surgeons responded to the survey. Of 236,015 shoulder procedures performed over the last five years, 14,277 (6%) involved the use of thermal energy (1,077 involved laser energy; 9,013, monopolar radiofrequency; and 4,187, bipolar radiofrequency) for the treatment of glenohumeral instability. The rates of recurrent instability after laser, monopolar radiofrequency, and bipolar radiofrequency capsulorrhaphy were 8.4%, 8.3%, and 7.1%, respectively. Of the patients with recurrent instability, 363 (twenty-one treated with laser energy, 220 treated with monopolar radiofrequency, and 122 treated with bipolar radiofrequency) required revision surgery. In this group of patients with revision surgery, seven (33%) of the twenty-one treated primarily with laser energy, thirty-nine (18%) of the 220 treated primarily with monopolar radiofrequency, and twenty-five (20%) of the 122 treated primarily with bipolar radiofrequency exhibited signs of capsular attenuation at the time of the revision. A total of 196 patients (1.4%) (three treated with laser energy; 133, with monopolar radiofrequency; and sixty, with bipolar radiofrequency) had a postoperative axillary neuropathy; 93% of the 196 had a sensory deficit only. Of these patients, 95% recovered completely, with the sensory deficits lasting an average of 2.3 months and the combined deficits, an average of four months.

CONCLUSIONS

The use of thermal energy for the treatment of shoulder instability has promising short-term results. The rates of recurrent instability are low. However, when recurrent instability occurs, capsular insufficiency may be present. Axillary nerve injury was reported in 1.4% of the patients, in most of whom it resolved spontaneously.

Thyroid status affects number and localization of thyroid hormone receptor expressing mast cells in bone marrow

Thyroid hormone (T(3)) plays a key role in endochondral ossification. The process relies on the coordinated synthesis and degradation of cartilage matrix and is disrupted in juvenile hypothyroidism, leading to abnormal skeletal development. Mast cells synthesize and store matrix-degrading enzymes. We examined whether thyroid status influences skeletal mast cell distribution in growing rats to determine whether they might modulate the actions of T(3) in bone. Tibiae were collected for histological, histochemical, immunohistochemical, and immunofluorescence analysis. Mast cells were increased throughout the bone marrow in hypothyroid rats compared with euthyroid, thyrotoxic, and hypothyroid-thyroxine replaced animals. Large numbers were present in metaphyseal marrow adjacent to the growth plate in hypothyroid animals and cells were distributed evenly throughout the marrow. Very few mast cells were present in metaphyseal marrow in other groups, but their numbers increased with increasing distance from the growth plate. T(3) receptor alpha1 (TRalpha1) was expressed in the nucleus and cytoplasm of skeletal mast cells, whereas TRalpha2 and TRbeta1 were restricted to the cytoplasm. Localization of TRs was not affected by altered thyroid status. Thus, disrupted endochondral ossification in hypothyroidism may be mediated in part by skeletal mast cells, which express TR proteins and may function as T(3) target cells.

Reflection: possible strategies to improve its use by qualified staff

Reflection is now a prerequisite for all nurses, midwives and health visitors (UKCC, 2001). It is the method endorsed by the UKCC to promote the development of informed, knowledgeable and safe practice, and qualified practitioners are required to maintain a personal professional profile containing evidence of reflection on practice. The aim of this article is to examine why qualified practitioners may be reluctant to reflect formally, to speculate on the possible barriers to reflection, and to suggest how reflection can be promoted positively as an integral part of nursing practice. The article begins with an examination of definitions of reflection, reflective theory and the purpose of reflection, and continues by questioning whether the concept of reflection has been embraced as eagerly by nurses at 'grass roots' as it has by academia, the nursing press and the UKCC. It is suggested that several barriers to effective reflection may create a division between practitioners and the professional hierarchy regarding the conceived common practice of reflection, and strategies are proposed that may help to overcome these barriers. The discussion concludes by prioritizing the need for a clear definition and concept analysis of reflection, supported by long-term investment into research that explores the effect of reflection on clinical practice and patient care.