Parental optimism about childhood obesity-related disease risks.

OBJECTIVES: Most parents believe childhood obesity is a problem for society, but not for their own children. We sought to understand whether parents' risk assessment was skewed by optimism, the tendency to overestimate one's chances of experiencing positive events. METHODS: We administered a national web-based survey to 502 parents of 5-12-year-old children. Parents reported the chances that (a) their child and (b) 'a typical child in their community' would be overweight or obese, and develop hypertension, heart disease, type 2 diabetes and depression in adulthood. Respondents self-reported demographic and health information, and we obtained demographic and health information about the typical child using zip code-level census and lifestyle data. We used regression models with fixed effects to evaluate whether optimism bias was present in parent predictions of children's future health outcomes. RESULTS: Parents had 40 times lower adjusted odds (OR=0.025, P<0.001, 99% CI: 0.006, 0.100) of predicting that their child (versus a typical child) would be overweight or obese in adulthood. Of the 20% of parents who predicted their child would be overweight in adulthood, 93% predicted the typical child would also be overweight in adulthood. Controlling for health and demographic characteristics, parents estimated that their children's chances of developing obesity-related comorbidities would be 12-14 percentage points lower those that of a typical child. CONCLUSIONS: Parent risk assessment is skewed by optimism, among other characteristics. More accurate risk perception could motivate parents to engage in behavior change.

The desaturation response time of finger pulse oximeters during mild hypothermia.

Pulse oximeters may delay displaying the correct oxygen saturation during the onset of hypoxia. We investigated the desaturation response times of pulse oximeter sensors (forehead, ear and finger) during vasoconstriction due to mild hypothermia and vasodilation caused by glyceryl trinitrate. Ten healthy male volunteers were given three hypoxic challenges of 3 min duration under differing experimental conditions. Mild hypothermia increased the mean response time of finger oximeters from 130 to 215 s. Glyceryl trinitrate partly offset this effect by reducing the response time from 215 to 187 s. In contrast, the response times of the forehead and ear oximeters were unaffected by mild hypothermia, but the difference between head and finger oximeters was highly significant (p < 0.0001). The results suggest that the head oximeters provide a better monitoring site for pulse oximeters during mild hypothermia.

The effect of remifentanil on the middle latency auditory evoked response and haemodynamic measurements with and without the stimulus of orotracheal intubation.

BACKGROUND AND OBJECTIVE: Changes in the middle latency auditory evoked response following the administration of opioids have been shown. However, it remains unclear as to whether these changes are due to a direct depressant effect of opioids on the middle latency auditory evoked response itself, or an indirect effect on account of their action in attenuating central nervous system arousal associated with noxious stimuli. By comparing changes in the middle latency auditory evoked response in intubated and non-intubated patients, receiving saline or remifentanil in different doses, this study attempts to answer this question. METHODS: Fifty-four patients were anaesthetized with isoflurane and nitrous oxide (0.9 MAC) and randomized to 1-6 groups. Groups 1-3 received a bolus injection of either saline 0.9%, low-dose remifentanil (1 microg kg(-1)) or high-dose remifentanil (3 microg kg(-1)) prior to intubation of the trachea. Groups 4-6 were not intubated following the bolus injection. RESULTS: Pa and Nb amplitudes of the middle latency auditory evoked response increased by 82% and 79% with intubation in the saline group (P < 0.005) and these changes were not seen in the patients given remifentanil. There was a significant linear trend for the reduction in Pa and Nb amplitude with increasing remifentanil dose (P < 0.05). In the absence of endotracheal intubation remifentanil had no effect on either the amplitudes or latencies of the waves Pa and Nb and there was no effect of dose. For the haemodynamic measurements remifentanil attenuated the pressor response to intubation (P < 0.001) and had a significant dose-related effect (P < 0.001) in the absence of intubation. CONCLUSIONS: We demonstrated an effect of remifentanil on both the middle latency auditory evoked response and haemodynamic changes to endotracheal intubation. For the non-intubated patients there was only an effect of remifentanil on the haemodynamic measurements. This suggests that remifentanil has an effect on the middle latency auditory evoked response in attenuating the arousal associated with intubation of the trachea but has no effect in the absence of a stimulus.

Effects of different concentrations of sevoflurane and desflurane on subcortical somatosensory evoked responses in anaesthetized, non-stimulated patients.

Twenty-four patients were recruited and given either sevoflurane or desflurane as their sole anaesthetic. Each patient was given sequentially increasing or decreasing doses at 0.5 MAC intervals, and the median nerve somatosensory evoked response recorded after an equilibration at each concentration. The N20-P25 and P25-N35 amplitudes decreased with increasing agent concentration. However, for both agents the P15-N20 amplitude response was quadratic in shape. The peak inflection points were at 3.2% for sevoflurane and 4.9% for desflurane. There were no differences between the ascending and descending groups. This increase in activity in the midbrain at 'surgical' end-tidal anaesthetic concentrations suggests more complex neuroelectrical responses to anaesthesia than simple global suppression.

A re-appraisal of wood-fired combustion.

Targets for a considerable increase in electricity generation from renewables have been set in order to reduce greenhouse gas emissions and fossil fuel dependence. Extensive planting of willow, poplar and alder as energy crops has been planned for power generation plants which use wood as the fuel. The current trend is to use gasification or pyrolysis technology, but alternatively a case may be made for wood combustion, if wood becomes readily available. A range of wood-fired circulating fluidised bed combustion (CFBC) plants, using from 10 to 10,000 dry tonne equivalent (DTE)/day, was examined using the ECLIPSE process simulation package. Various factors, such as wood moisture content, harvest yield, afforestation level (AL) and discounted cash flow rate (DCF) were investigated to test their influence on the efficiency and the economics of the systems. Steam cycle conditions and wood moisture content were found to have the biggest effects on the system efficiencies; DCF and AL had the largest influences on the economics. Plants which could handle more than 500 dry tonnes/day could be economically viable; those using more than 1000 dry tonnes wood/day could be competitive with large-scale, conventional coal-fired plants, if sufficient wood were available.

Monocyte-derived giant cell formation in patients with breast cancer.

Recent reports of monocyte-derived giant cell formation in breast cancer and associated retroviral findings have attracted much interest in the scientific literature and with the media, revitalising hypotheses of a viral role in the aetiology of the disease. We describe an assay developed to investigate further the giant cell forming phenomenon and report results which conflict with earlier work. We observed a smaller proportion of patients with breast cancer forming giant cells than in previous reports. Conversely, a much larger proportion of controls formed giant cells. Using our assay to calculate a fusion index the formation of giant cells, as defined in earlier work, was found to be a poor indicator of the degree of cell fusion in our samples. We discuss our experiences with the assay and suggest the calculation of a fusion index as a more comparable and quantitative measurement of cell fusion.

Chest tube perforation of esophagus following repair of esophageal atresia.

The two major acute thoracic complications of closed chest tube thoracostomy are pulmonary laceration and vascular compression. We have noted that closed chest tube thoracostomy can also perforate an esophageal anastomosis or myotomy site. Clinically, such a perforation produces a profuse discharge of gas and/or fluid through a chest tube positioned at the level of the anastomosis or myotomy site. Plain films demonstrate an accumulation of extrapleural gas and/or fluid adjacent to the distal portion of the chest tube. If untreated, these accumulations may form into an extrapleural abscess.

Successful pregnancy and vaginal delivery after heart transplantation.

Successful pregnancy and delivery in women with serious cardiovascular diseases have been reported. We describe here a patient with a transplanted heart, treated with cyclosporine and prednisone, who underwent pregnancy and vaginal delivery with good outcomes for mother and infant.

Evolution of single-copy DNA and the ADH gene in seven drosophilids.

Single-copy DNA was isolated from Drosophila melanogaster and hybridized with total genomic DNA of D. melanogaster, D. mauritiana, D. simulans, D. pseudoobscura, D. willistoni, D. hydei and D. virilis. The duplexes were thermally eluted from hydroxyapatite and the data used to assess the relatedness of each species to D. melanogaster. The general pattern of relatedness was similar to that predicted by morphological methods but with some notable exceptions. The rate of nucleotide substitution was estimated to be greater than 0.66% of bases per million years. An unexpected, rapidly evolving component of D. melanogaster single-copy DNA was identified. The relatedness of these species was also studied with respect to the gene coding for alcohol dehydrogenase (ADH). The ADH gene, previously cloned from D. melanogaster (Goldberg 1980), was hybridized with Southern blots of genomic digests of the seven species. The intensity and position of the hybridizing bands suggest the amount of divergence of the gene. Divergence was quantitated by reassociation of a fragment of the cloned ADH gene with total DNA of the seven drosophilids and thermal elution of the resultant duplexes from hydroxyapatite. The ADH gene was isolated from genomic clone libraries of D. melanogaster, D. simulans and D. mauritiana and further studied by comparison of position of restriction sites. Species relationships deduced from comparison of total single-copy DNA and the ADH gene were consistent, demonstrating that a single gene can reflect divergence of the entire genome.

Bone resorption in organ culture: inhibition by the divalent cation ionophores A23187 and X-537A.

The ionophores A23187 and X-537A were used as probes to investigate the possible role of calcium uptake by bone as a mediator for the stimulation of bone resorption induced by parathyroid hormone (PTH) and other agents in cultured mouse calvaria. The ionophores alone at concentrations from 1 nM to 20 muM did not stimulate bone resorption, nor did they potentiate bone resorption stimulated by submaximal concentrations of PTH after either brief (15-60 min) or extended (1-3 day) exposure to the ionophores. Unexpectedly, we found that the ionophores inhibit in a dose-dependent manner bone resorption stimulated by PTH and a wide variety of other compounds (prostaglandin E2, 1alpha-hydroxycholecalciferol, 3-isobutyl-1-methyl-xanthine, and phorbol myristate acetate). This inhibition was not due to irreversible damage to the bones by the ionophores, because the inhibition was reversible even after 24 h of treatment. Inhibition of bone resorption by the ionophores was observed in media of both high and low calcium concentration, indicating that the inhibition was not due to a critical extracellular calcium concentration. Inhibition by the ionophores differs qualitatively in several ways from that produced by calcitonin, a natural inhibitor of bone resorption. Furthermore, A23187 at 1.0 mug/ml had no effect on the accumulation of cyclic AMP in the medium of either control, PTH- or calcitonin treated calvaria. We conclude that the ionophores A23187 or X537A do not stimulate bone resorption nor potentiate the effects of stimulators of bone resorption; instead they are inhibitors of bone resorption stimulated by a wide variety of compounds.

Studies on "big" growth hormone from human plasma and pituitary.

Most of the immunoreactive growth hormone (IRGH) in human plasma elutes from Sephadex G-75 as "little" GH (LGH), mol wt 22,000, but 14-39% elutes earlier ("big" GH, BGH). In saline extracts of human pituitary, 11-17% of IRGH eluted as BGH. On gel filtration of pituitary and plasma BGH in 8 M urea, 59-81% ran as LGH, but when the remaining BGH was refiltered in urea, all ran as BGH. Thus there is a "urea-stable" and a "urea-labile" form of BGH. SImilarly, freezing and thawing converted over half of pituitary and plasma BGH to LGH, but when the "freeze-stable" BGH was again frozen, thawed, and refiltered, almost all ran as BGH. Urea-stable BGH was not dissociated by freezing, and most of the freeze-stable BGH was stable in urea, so the two forms are very similar or identical. Since 8 M urea and freezing dissociate peptides linked by noncovalent bonds, probably the BGH that is dissociated by urea and freezing consists of LGH bound noncovalently to another moiety, while in stable BGH the LGH is bound to another molecule by covalent or unusually strong noncovalent linkage. On centrifugation, the sedimentation of urea-stable BGH was consistent with a mol wt about twice that of LGH. Trypsinization of urea-stable BGH converted 36-59% to LGH, suggesting that some BGH may be a "prohormone" of LGH. On retrypsinization of the BGH that was not converted to LGH, only 13-24% converted, suggesting that there may be two forms of urea-stable BGH which vary in their response to trypsin.