The effect of increasing risk and challenge in the school playground on physical activity and weight in children: a cluster randomised controlled trial (PLAY).

BACKGROUND: To investigate whether changing the play environment in primary schools to one that includes greater risk and challenge increases physical activity and reduces body mass index (BMI). SUBJECTS/METHODS: A 2-year cluster randomised controlled trial was undertaken in 16 New Zealand schools (years 1-8). Intervention schools (n=8) redesigned their play environments to encourage imaginative and independent free play by increasing opportunities for risk and challenge (for example, rough-and-tumble play), reducing rules and adding new playground components (for example, loose parts). Control schools (n=8) were asked to not change their play environment. A qualified playworker rated all school play environments at baseline and 1 year. Primary outcomes were moderate-to-vigorous physical activity (7-day accelerometry) and BMI z-score, collected in 840 children at baseline, 1 and 2 years. Data were analysed using generalised estimating equations. RESULTS: Multiple changes were made to the school play environments resulting in a significant difference in overall play evaluation score between intervention and control schools of 4.50 (95% confidence interval: 1.82 to 7.18, P=0.005), which represents a substantial improvement from baseline values of 19.0 (s.d. 3.2). Overall, schools liked the intervention and reported many benefits, including increased physical activity. However, these beliefs did not translate into significant differences in objectively measured physical activity, either as counts per minute (for example, 35 (-51 to 120) during lunch break) or as minutes of moderate-to-vigorous physical activity (0.4, -1.1 to 2.0). Similarly, no significant differences were observed for BMI, BMI z-score or waist circumference at 1 or 2 years (all P>0.321). CONCLUSIONS: Altering the school play environment to one that promoted greater risk and challenge for children did not increase physical activity, nor subsequently alter body weight. Although schools embraced the concept of adding risk and challenge in the playground, our findings suggest that children may have been involved in different, rather than additional activities.

Measuring physical activity and sedentary behaviors in women with young children: a systematic review.

Current evidence indicates that women with young children are less active than women without children. In this review the authors investigated the methods of measuring physical activity employed in studies of women with young children (aged 1-5 years) and the associated challenges in measurement. Articles from databases (MEDLINE, OVID, CINAHL, Google Scholar) and manual searches were limited to English peer-reviewed journals published from 1990 to 2010. Studies that included measurement of physical activity in samples of women with young children were selected. Measurement properties were extracted, and original reliability and validity articles were reviewed for physical activity measurement tools used by 15 samples. The evidence base was dominated by self-report measurement tools, many of which assessed leisure-time physical activity only. Use of motion sensors to assess physical activity in this population was limited. It is likely that much of the habitual physical activity performed by women with young children has not been captured by self-report measures. Further investigation should be undertaken using tools that capture adequately all health-enhancing physical activity among women with young children.

Studies on the depletion and accumulation of microvilli and changes in the tubulovesicular compartment of mouse parietal cells in relation to gastric acid secretion.

Gastric parietal cells in mice present a spectrum of microscopic appearances due mainly to variations in the abundance of the tubular and vesicular component of the cytoplasm and in the size and number of microvilli lining the intracellular canaliculi. Differences in the range of forms among parietal cells of fasting versus fed mice were not especially striking, but cells with very numerous tubules and vesicles were more common after fasting. However, in mice treated with drugs or hormones that induce acid secretion, parietal cells were more uniform in appearance. There was a marked reduction of these cytoplasmic membranes and a concomitant increase in both the number and size of microvilli. Measurements of acid secretion in control animals and in animals treated with acid secretagogues indicated hydrogen ion secretion contemporaneous with depletion of the cytoplasmic tubulovesicular membranes and with increase of the microvilli. In mice with inhibited acid secretion, parietal cells showed an accumulation of cytoplasmic tubules and vesicles and reduction in the numbers of microvilli. Stereological methods were used to quantitate 10 different parietal cell compartments. Tracer studies with lanthanum did not reveal continuity between the tubules and the plasma membrane. However, there were regions of close apposition between the tubulovesicular membranes and the cell membrane of the canaliculus, and instances where cytoplasmic tubules extended from the cell into the core of enlarged microvilli.

Pedometer steps in primary school-aged children: a comparison of school-based and out-of-school activity.

While studies of the physical activity habits of New Zealand children have been carried out, the findings have been restricted by the use of proxy and self-report measures and limited to total overall daily activity. Objective measurement of children's in-school and out-of school physical activity using pedometry is likely to provide more accurate data on habitual daily activity. To date, no such data are available for New Zealand children. In the present study, children from school years 1-6 (girls, n=46; boys, n=45) at a New Zealand primary school wore a Yamax Digiwalker SW-200 pedometer to record school-based and out-of-school steps over a 3-day period. Mean daily steps for the overall sample were 14 333 (S.D.=4110). Boys (X=15 606; S.D.=4601) were significantly more active than girls (X=13 031; S.D.=3079) (p=.00). Mean steps were also significantly higher in older age groups for both boys (p=.03) and in particular, girls (p=.00). Of note, for the overall sample, steps taken out of school made up 52.4% of total daily steps. Girls (53.6%) and boys (51.3%) took a similar proportion of their overall daily steps outside of the school environment. While a significant difference was found between the most and least active tertiles in steps taken during both during school hours (p=.00) and outside of school hours (p=.00), the most active third of the sample completed significantly more of their daily steps outside of school (55.1%) than did their least active (46.7%) counterparts (p=.00). These results suggest that physical activity outside of the school environment is a key contributor to a child's overall level of physical activity, reinforcing the need for interventions targeting the family and community as well as the school environment.

Objectively-measured physical activity in New Zealand workers.

To date, no objective measurements of New Zealanders' physical activity have been reported. The relative contribution of work time activity to total daily physical activity by gender and occupational category has also not been measured objectively in any population. The present study reports such data using pedometer steps counts to quantify both work and non-work physical activity in a sample of New Zealand adult workers in six different occupational categories over a three-day period. Females (9943+/-3855 steps) had slightly higher, but not significantly different (F=0.084(1,179)1, p=0.772) daily step counts than males (9766+/-3965 steps). Using the 10 000 steps a day criterion, 57% of the sample were considered at least low-active. Analysis of variance was used to identify between group (occupational) differences in workplace physical activity (F=11.189(5,175), p<0.001), non-work physical activity (F=2.596(5.175), p=0.027), and total physical activity (F=6.265(5,175), p<0.001). Tukey post hoc comparisons showed significant differences with retail and blue collar workers achieving higher activity levels in comparison to the other occupational categories in work and total physical activity. Odds ratios were calculated to find the odds of being in the top half of activity classification for work and non-work physical activity by tertile splits of work time, active transportation use, sport and exercise participation, television and computer viewing, and passive recreation. Active transportation and passive recreation were related to increased odds of higher work pedometer steps. For non-work pedometer values, television and computer use increased the likelihood of being in the lowest activity group, while sport and exercise participation were associated with increased activity levels.

Development of a psychometrically valid and reliable sports nutrition knowledge questionnaire.

The present range of sports nutrition knowledge questionnaires have inadequate psychometric validation, and few are up to date in a rapidly changing discipline. The purpose of this study was to design a sports nutrition questionnaire that satisfied acceptable psychometric criteria of validity (content and construct) and reliability (test-retest). The questionnaire was designed by an expert panel of six sports dietitians and distributed to five groups, selected for their expected variation in sports nutrition knowledge. Dietitians, university business staff and nutrition students received questionnaires via e-mail. The response rates obtained were 21.3% (n = 49), 34.4% (n = 33), and 72.0% (n = 18), respectively. University business and fitness students completed questionnaires during class time. Response rates were 52.3% (n = 23) and 75.4% (n = 49), respectively. The questionnaire was administered a second time to the business staff and the dietitians to assess test-retest reliability. Two methods were used: 1, Pearson's product-moment correlation; and 2, a percentage calculation of questions answered in an identical manner on both test occasions. Reliability was acceptable with Method 1 yielding acceptable values (r = 0.74-0.93), aside from the fluid sub-category (r = 0.52). Method 2 showed good test-retest concordance with 81.2% duplication of responses of all questions. Construct validity was high, as indicated by significant mean knowledge score differences between the groups (p = 0.0001). Dietitians and nutrition students achieved significantly greater mean scores than the remaining groups. The findings of this study indicate that the questionnaire is suitably valid and reliable to be used in research and practice to determine sports nutrition knowledge.

When does a human being die?

For most of human history there has been no particular importance of establishing the exact time of a person's death, only whether the person is alive or dead. With modern medical advances, however, more precise answers are looked for. For a definition of death to succeed is important that it is a universal definition and that under it, all human beings are correctly identified as alive or dead. This article initially examines the most commonly proposed positions on when a human being dies those of cardiopulmonary death, whole brain death, brainstem death and higher brain death and for each describes scenarios that provide counter-intuitive results. Intuition is used as a benchmark as this is what our patients most commonly use. The second part of the article seeks to establish a more robust definition of death. We argue that death is an event that takes place at a set point in time, when the collection of bodily processes that maintains homoeostasis finally cease. Based upon defining 'human being' as being in possession of human DNA and Olsen's Animalism, the model is applicable to a full lifespan and maintains personal identity throughout the course of life. That this conclusion will interfere with clinical practice concerning organ transplantation is considered, but countered with the argument that there has been a conflation of the normative question of timing of organ retrieval for transplantation with the metaphysical question of what is death.

Implementation of a quality improvement programme to support advance care planning in five hospitals across a health region.

OBJECTIVES: Advance care planning (ACP) can help patients with a terminal illness to prepare for the end of their lives. This report describes a regional service improvement initiative to increase the identification of hospital inpatients at this stage in their illnesses and to increase the number of such patients who are offered the opportunity to start the process of ACP. METHODS: Data were collected prospectively over a 7 month period from four acute hospital trusts and a specialist cancer centre in the South-West London region. Each unit identified a specific patient population who were screened for eligibility to engage in the process of ACP. Data concerning the reasons for eligibility, the suitability for discussion and the various reasons why patients did not complete the process, were recorded. RESULTS: Over a 7 month period 1980 patients were screened and 559 (28.2%) were found to be potentially eligible for an ACP discussion. Of these 227/559 (40.6%) were deemed suitable for a discussion by medical staff. The majority of these patients (195/227; 86%) were offered the opportunity to undergo ACP discussions and 144/195 (73.8%) agreed to begin the process of ACP. CONCLUSIONS: This report shows that a targeted approach can result in increased uptake in the number of patients who engage in ACP. However, systematic identification of potentially eligible patients requires a significant investment of clinical time and resources.

Thimerosal increases the responsiveness of the calcium receptor in human parathyroid and rMTC6-23 cells.

Parathyroid cells express a plasma membrane calcium receptor (CaR), which is stimulated by a rise in extracellular calcium concentration ([Ca2+]ext). A decreased sensitivity to [Ca2+]ext occurs in adenomatous parathyroid cells in patients with primary hyperparathyroidism, but the underlying functional mechanism is not yet fully understood. This study explored whether CaR responsiveness is influenced by increasing the affinity of IP3 receptors--a major signalling component of other G-protein-coupled receptors. The sulphydryl reagent thimerosal was used to increase the responsiveness of IP3-receptors. Quantitative fluorescence microscopy in Fura-2-loaded cells was used to investigate the effects of thimerosal on the cytoplasmic calcium concentrations ([Ca2+]i) in human parathyroid cells and to compare its effects in a rat medullary thyroid carcinoma cell line (rMTC6-23) also expressing CaR. During incubation in Ca(2+)-free medium, thimerosal 5 microM induced a rapid sustained rise in [Ca2+]i in human parathyroid cells and no further [Ca2+]i increase appeared in response to the CaR agonist Gd3+ (100 microM). Thimerosal 1 microM induced only slow and minimal changes of basal [Ca2+]i and allowed a rapid response to Gd3+ 20 nM (a concentration without effect in control cells). The slope of the thimerosal-induced [Ca2+]i responses was steeper following exposure to CaR agonists. In the presence of 1 mM [Ca2+]ext, thimerosal (0.5 microM) induced a sharp increase in [Ca2+]i to a peak (within 60 s), followed either by return to basal [Ca2+]i or by a plateau of slightly higher amplitude. Similar results were obtained using rMTC6-23 cells. Thimerosal increases the responsiveness to CaR agonists through modulation of the sensitivity of the IP3 receptor in both parathyroid and rMTC6-23 cells.

Neurotransmission through sympathetic ganglia of spontaneously hypertensive rats.

Transmission of neuronal activity was assessed by recording preganglionic and postganglionic compound action potentials in superior cervical ganglia isolated from adult spontaneously hypertensive rats (SHR), Wistar-Kyoto (WKY) rats, and Wistar rats as well as young SHR and WKY rats to determine if previously observed alterations of membrane excitability, synaptic transmission, or both, have an effect on the transmission of preganglionic activity in SHR. Single stimuli induced more postganglionic neurons to fire over a wide range of preganglionic stimulation intensities in superior cervical ganglia from adult SHR as compared with those from adult normotensive controls. Short stimulation trains confirmed that SHR are able to maintain this greater number of active postganglionic neurons during low-frequency stimulation (1-20 Hz). However, by the end of a train of high-frequency stimulation (70-100 Hz) fewer neurons fired in ganglia from SHR compared with those from normotensive controls. These differences in transmission were not observed in the young rats. The results from the present study demonstrate that physiological frequencies of preganglionic activity are more effectively transmitted through sympathetic ganglia from adult SHR compared with those from normotensive controls, and this enhanced transmission through ganglia may contribute to the elevated sympathetic activity and the consequent hypertension seen in this model.

Room temperature culture extends the useful life of adult neurons for voltage-clamp experiments.

Isolated superior cervical ganglion (SCG) neurons were maintained in vitro at 22 degrees C (22 degrees C neurons) for up to 4 days in an effort to inhibit process outgrowth and thus extend the useful life of SCG neurons for voltage-clamp experiments. The neurons were viable after 4 days in vitro and remained roughly spherical whereas neurons maintained in vitro at 37 degrees C (37 degrees C neurons) developed extensive neurite processes after 2 days. The resting potential of 22 degrees C neurons was more hyperpolarized and the action potential duration was reduced compared to acutely isolated neurons (acute neurons) or 37 degrees C neurons. The steady state Na+ current activation and inactivation parameters of the acute and 22 degrees C neurons were similar whereas the half activation voltage was hyperpolarized and the slope factor of inactivation was reduced for the 37 degrees C neurons compared to the other two groups. The Na+ currents recorded from the 37 degrees C neurons displayed obvious signs of poor voltage control which were not observed in the acute or 22 degrees C neurons. The acetylcholine (ACh) sensitivity of both 22 degrees C and 37 degrees C neurons was significantly less than that of the acute neurons. This report demonstrates that room temperature culture of SCG neurons is a simple method which prevents process outgrowth and thus extends the useful life of the neurons for voltage-clamp experiments.

Ca2+ currents of fast blue-labeled superior cervical ganglion neurons.

To investigate if Ca2+ currents of acutely isolated superior cervical ganglion (SCG) neurons are altered after dye labeling or ultraviolet (UV) exposure, SCG neurons were labeled by multiple injections of 2% fast blue (FB) (5-microliters total) into the submaxillary gland. Ca2+ currents of both labeled and unlabeled neurons were significantly depressed by 2-min exposure to UV, compared to labeled and unlabeled neurons not exposed to UV. The I-V curve of labeled neurons was shifted hyperpolarized after UV exposure. Tail-current activation curves of both labeled and unlabeled neurons were fitted to a double Boltzmann equation. In labeled neurons, 2-min exposure to UV produced a significant reduction of the amplitude of the more depolarized component as well as a hyperpolarizing shift of the half activation potential of both components of the activation curve. However, the short time (< 10 s) required to identify a target-specific neuron had no significant effect on the biophysical properties of Ca2+ currents of FB-labeled SCG neurons. Thus, use of this label in combination with the patch-clamp technique comprises a powerful approach to study membrane currents of target-specific neurons.

Potassium currents of acutely isolated adult rat superior cervical ganglion neurons.

K+ currents of adult rat superior cervical ganglion neurons were studied using the voltage-clamp technique. Neuronal somata were dissociated from the ganglion using an enzymatic dispersion technique and voltage-clamped using the whole-cell patch-clamp technique. In solutions designed to isolate K+ currents, depolarization from a prepulse potential of -100 mV induced both transient and sustained outward current components. The transient current was completely eliminated by depolarization to -50 mV. The remaining sustained current component could be separated further into Ca2+-sensitive and Ca2+-insensitive components by superfusion with a Ca2+-free external solution. The transient current, which could be isolated by digital subtraction, rose rapidly and decayed over the subsequent 80 ms. Reversal potential determinations in different K+-containing solutions demonstrated that the current was carried primarily by K+. The transient current showed voltage-dependent inactivation, showing 50% inactivation near -87 mV and was completely inactivated at potentials more positive than -60 mV. The transient current recovered from inactivation with a voltage-dependent time course, the time course of inactivation decreasing with hyperpolarization. This transient outward current had characteristics of IA. The sustained Ca2+-insensitive outward current showed little decay over 800 ms and was also carried primarily by K+. This current component had characteristics similar to the delayed rectifier. A third sustained outward current eliminated by superfusion with Ca2+-free external solution had characteristics similar to the Ca2+-dependent K+ current.

Single acetylcholine channel currents in sympathetic neurons.

Single acetylcholine (ACh) channel currents were studied by the gigaohm patch-clamp technique in cultured sympathetic neurons of the bullfrog, Rana catesbeiana. Recordings were made at 22 degrees C on cell-attached and excised membrane patches. When ACh (0.5-1 microM) was present in the pipette, a single class of inward currents was observed with a chord conductance of 30 pS and a reversal potential of -2 mV. The mean channel open time was 11.6 ms at -65 mV and showed little or no voltage-dependence over the range -85 to -45 mV. These channels appear to mediate the fast nicotinic excitatory postsynaptic current.

Norepinephrine inhibits a Ca2+ current in rat sympathetic neurons via a G-protein.

The effects of norepinephrine on a Ca2+ current from acutely isolated and short-term (24 h) cultured adult rat superior cervical ganglion neurons were studied using the whole-cell variant of the patch-clamp technique. Norepinephrine produced a rapid, reversible and concentration-dependent reduction of the Ca2+ current. Accurately timed applications of norepinephrine (3 microM) showed that the development of Ca2+ current inhibition was delayed by up to 11 s after application of norepinephrine. Internal 500 microM guanylyl-imidodiphosphate (Gpp(NH)p) or guanosine-5'-O-(3-thiotriphosphate) (GTP-gamma-S) decreased the Ca2+ current amplitude and induced a biphasic rising phase of the Ca2+ current. Under these conditions, the reduction of Ca2+ current amplitude by 3 microM norepinephrine was virtually abolished when compared with cells dialysed with GTP-containing internal solutions. Internal dialysis with solutions containing 2 mM guanosine-5'-O-(2-thiodiphosphate) (GDP-beta-S) increased the Ca2+ current amplitude and reduced the inhibition produced by 3 microM norepinephrine compared to cells dialysed with control internal solution. Treatment with 200 ng/ml pertussis toxin for 12-16 h greatly reduced the norepinephrine-induced Ca2+ current inhibition. Internal dialysis with solutions containing 500 microM cyclic adenosine 3',5'-monophosphate (cyclic AMP) and 3-isobutyl-1-methylxanthine had no significant effect on either the Ca2+ current inhibition by norepinephrine or the Ca2+ current amplitude. These results suggest that norepinephrine blocks a Ca2+ current in adult rat superior cervical ganglion neurons via a pertussis toxin-sensitive G-protein which is independent of intracellular cyclic AMP.

Norepinephrine blocks a calcium current of adult rat sympathetic neurons via an alpha 2-adrenoceptor.

The effects of alpha-adrenoceptor agonist and antagonist drugs on the Ca2+ current of acutely isolated adult rat superior cervical ganglion (SCG) neurons were investigated to characterize the adrenoceptor which mediates a catecholamine-induced decrease of the Ca2+ current. Ca2+ currents were recorded using the whole-cell variant of the patch-clamp technique from neurons isolated enzymatically from adult rat SCG. Norepinephrine (1 microM) produced a rapid, reversible, and concentration-dependent decrease in Ca2+ current amplitude and slowed the rising phase of the Ca2+ current. These effects could be mimicked by clonidine (1 microM), an alpha 2-agonist but not by the alpha 1-agonist phenylephrine (1 microM). The norepinephrine-induced decrease in Ca2+ current amplitude was attenuated in the presence of idazoxan (1 microM), an alpha 2-antagonist, but was unaffected in the presence of the alpha 1-antagonist prazosin (1 microM). Neither antagonist displayed any Ca2+ current blocking activity. These results suggest that the alpha-receptor which mediates the norepinephrine-induced decrease of the Ca2+ current in adult rat SCG neurons is of the alpha 2-subtype.

Nitric oxide modulates Ca2+ channel currents in rat sympathetic neurons.

The effects of nitric oxide on the Ca2+ channel currents of adult rat superior cervical ganglion neurons were investigated using the whole-cell patch-clamp technique. Nitric oxide-containing compounds sodium nitroprusside and S-nitroso-N-acetyl-penicillamine increased the amplitude of Ca2+ currents by intracellular application. In addition, both sodium nitroprusside and S-nitroso-N-acetylpenicillamine reduced norepinephrine-induced inhibition of Ca2+ currents. The results suggest that nitric oxide might be involved in the modulation of Ca(2+)-dependent neurotransmission in sympathetic neurons.

Norepinephrine-induced Ca2+ current inhibition in adult rat sympathetic neurons does not require protein kinase C activation.

Experiments were performed to investigate if protein kinase C is involved in the norepinephrine-induced alpha 2-adrenoceptor-mediated inhibition of the Ca2+ current in adult rat superior cervical ganglion neurons. Ca2+ currents were recorded from dispersed superior cervical ganglion neurons, acutely isolated from adult rats, using the whole-cell patch-clamp technique. Both norepinephrine and the protein kinase C activator, 1,2-dioctanoylglycerol (diC8) decreased the Ca2+ current induced by step depolarizations to +10 mV from a holding potential of -80 mV. In the presence of norepinephrine, the Ca2+ current rising phase was adequately fit by a double exponential with a second time constant much larger than control, whereas in the presence of diC8 the rising phase became mono-exponential and the current displayed a prominent decay. Control tail current activation curves were described by the sum of two Boltzmann functions. Both norepinephrine and diC8 reduced peak tail current amplitude. Norepinephrine preferentially reduced the component activated at more hyperpolarized potentials, while diC8 preferentially reduced the component activated at more depolarized potentials. Intracellular application of three protein kinase C inhibitors: protein kinase C pseudosubstrate (PKC-19-36) (2 microM), staurosporine (1 microM) and 1-(5-isoquinolinylsulonyl)-2-sulfonylpiperazine (H-7) (50 microM), failed to affect norepinephrine-induced Ca2+ current inhibition. In addition, these protein kinase C inhibitors did not decrease the Ca2+ current inhibition induced by diC8.(ABSTRACT TRUNCATED AT 250 WORDS)

Neuropeptide Y blocks a calcium current in C cells of bullfrog sympathetic ganglia.

The effects of neuropeptide Y (NPY) on the Ca2+ current of enzymatically dispersed neuronal somata from bullfrog paravertebral sympathetic ganglia were investigated using the patch-clamp technique. In C neurons, NPY induced a concentration-dependent decrease in the amplitude of the Ca2+ current and induced a slow biphasic current rising phase. Upon removal of NPY these parameters returned to near control values. NPY had no discernable effect on the Ca2+ current recorded in B neurons.

The effect of pumiliotoxin-B on the excitability of bullfrog sympathetic neurons.

The effects of the alkaloid pumiliotoxin-B were investigated on neurons from bullfrog paravertebral ganglia using current-clamp techniques. Pumiliotoxin-B (2 microM) induced repetitive action potential discharge or bursting pacemaker activity in response to a single stimulus. The toxin had no significant effect on the mean resting potential or action potential characteristics of single action potentials evoked prior to the action potential discharge onset. During the action potential discharge, action potential threshold and afterhyperpolarization amplitude were decreased. In the presence of pumiliotoxin-B, single action potentials were followed by a depolarizing afterpotential. Pumiliotoxin-B still induced action potential discharge in Ca2+-free or Cd2+-containing solutions. Brief superfusion with a Na+-free or tetrodotoxin-containing solution abolished the pumiliotoxin-B-induced action potential discharge prior to the blockade of directly elicited single action potentials. These solutions decreased or abolished the depolarizing afterpotential. Pumiliotoxin-B increases membrane excitability and can induce a stimulation-dependent action potential discharge which appears to result from a tetrodotoxin-sensitive Na+-sensitive potential.