"That's His Choice Not Mine!" Parents' Perspectives on Providing a Packed Lunch for Their Children in Primary School.

OBJECTIVE: To examine factors influencing parents' selection of packed lunches over a school lunch, their choices in food preparation, and the role of children within these. DESIGN: A qualitative approach using semistructured focus group and individual interviews. SETTING: Four primary schools in a UK local authority. PARTICIPANTS: Twenty parents providing a packed lunch for their children (aged 5-11 years). ANALYSIS: An inductive thematic approach was used to identify categories and themes. The researchers maintained rigor in the data analysis through internal discussion and review until consensus was reached. RESULTS: Children emerged as active decision makers exerting substantial power particularly in the initial decision to have a packed lunch, and then in influencing the lunch's contents. The packed lunch could be a source of anxiety for some parents; however, ultimately parents' attitudes and perceptions revolved around the key requirement that the lunch was eaten. Providing a packed lunch was a means of achieving this. CONCLUSIONS: This study highlights children's growing authority over everyday food decisions. Further research is needed to explore children's perceptions of their role in food provision. The study's findings have implications for school food, nutrition education, and school-based interventions. Frameworks that look to improve children's nutrition in this area should reflect children's growing status as food decision makers and consider how this can be employed to support and sustain positive changes.

Stochastic precision analysis of 2D cardiac strain estimation in vivo.

Ultrasonic strain imaging has been applied to echocardiography and carries great potential to be used as a tool in the clinical setting. Two-dimensional (2D) strain estimation may be useful when studying the heart due to the complex, 3D deformation of the cardiac tissue. Increasing the framerate used for motion estimation, i.e. motion estimation rate (MER), has been shown to improve the precision of the strain estimation, although maintaining the spatial resolution necessary to view the entire heart structure in a single heartbeat remains challenging at high MERs. Two previously developed methods, the temporally unequispaced acquisition sequence (TUAS) and the diverging beam sequence (DBS), have been used in the past to successfully estimate in vivo axial strain at high MERs without compromising spatial resolution. In this study, a stochastic assessment of 2D strain estimation precision is performed in vivo for both sequences at varying MERs (65, 272, 544, 815 Hz for TUAS; 250, 500, 1000, 2000 Hz for DBS). 2D incremental strains were estimated during left ventricular contraction in five healthy volunteers using a normalized cross-correlation function and a least-squares strain estimator. Both sequences were shown capable of estimating 2D incremental strains in vivo. The conditional expected value of the elastographic signal-to-noise ratio (E(SNRe|ε)) was used to compare strain estimation precision of both sequences at multiple MERs over a wide range of clinical strain values. The results here indicate that axial strain estimation precision is much more dependent on MER than lateral strain estimation, while lateral estimation is more affected by strain magnitude. MER should be increased at least above 544 Hz to avoid suboptimal axial strain estimation. Radial and circumferential strain estimations were influenced by the axial and lateral strain in different ways. Furthermore, the TUAS and DBS were found to be of comparable precision at similar MERs.

Neonatal HIV-1 thymic infection.

The thymus is the primary site of T cell ontogeny and selection during fetal and neonatal development. Previous studies have established that the thymus is also a site of HIV-1 infection, as early as the first trimester of pregnancy. Alteration of the thymocyte maturation process by HIV-1 could impact on the peripheral T cell population and interfere with immune responses. A neonatal thymic organ culture system was established to study HIV-1 infection within the thymus. We have shown that this primary tissue isolate can support a productive HIV-1 infection. Infection occurred without detectable thymocyte cytopathology. The ability to infect the developing thymocyte within an intact micro environment will enable us to further establish the kinetics of acute HIV-1 thymic infection and its consequences on lymphocyte maturation.

Human neonatal thymic organ culture: an ex vivo model of thymocyte ontogeny and HIV-1 infection.

An intact thymic microenvironment is required for the normal maturation and selection of thymocytes. This process is directed by the interaction of thymocyte progenitors with molecules on the surface of thymic stromal cells and with cytokines. The precise nature of these events is poorly understood in humans. We have developed a technique of human neonatal thymic organ culture (hNTOC) that enabled thymocyte development for up to 14 days of ex vivo culture. hNTOC supported the maturation of CD4+CD8+ double-positive cells into both CD4+CD8- and CD4-CD8+ single-positive thymocytes. hNTOC was also used to examine infection with HIV-1, as a means to address the thymic pathology of HIV-1. These results establish an experimental system for the analysis of human thymic ontogeny and for the experimental manipulation of these events by ex vivo administration of cytokines, drugs or infectious agents.

Pharmacokinetics and pharmacodynamics following single and repeated nightly administrations of loprazolam, a new benzodiazepine hypnotic.

The pharmacokinetics of oral loprazolam and pharmacodynamic responses on the morning following nightly drug administration were examined after single and after seven consecutive 1 mg doses in six non-fasting healthy subjects. The serum concentration-time profiles for unchanged loprazolam measured by a specific high pressure liquid chromatography/gas chromatography (h.p.l.c./g.c.) method and for benzodiazepine material measured by radioimmunoassay (RIA) were qualitatively similar although RIA levels were consistently higher. Approximate elimination half-life of unchanged loprazolam after single doses was 8.0 h. For RIA measured material, approximate half-life was 11.7 h following acute administration and 12.8 h after seven consecutive doses. Compared to results after single doses, maximum serum concentration and AUC were greater following 1 week's treatment. Using RIA results, the increases were 27.2% (95% CL 6.9 to 47.4%) and 35.1% (95% CL 15.8 to 54.3%) respectively and using h.p.l.c./g.c. data, 11% (95% CL - 22.6% to 44.5%) and 41% (95% CL - 50.9 to 133.0%). After repeated doses of loprazolam, there were no significant changes with respect to results after single doses in psychomotor function assessed objectively by critical flicker fusion threshold or choice reaction time, or in sleep quality or behaviour on awakening assessed subjectively by 10 cm analogue scales. Mean time to maximum serum concentration was 4.95 h with considerable inter-individual variability (range 1-12 h) and there was a lag time of 1-1.5 h before drug was detectable in blood.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of prolactin secretion by low-dose dopamine infusion in patients with hyperprolactinaemia.

Dopamine inhibits the secretion of prolactin from the pituitary. We have examined the relation between plasma dopamine and serum prolactin in 12 patients with hyperprolactinaemia during the infusion of dopamine at low doses (0.01, 0.1 and 1 microgram/kg/min). Plasma dopamine levels were raised from less than 100 pg/ml at the lowest rate of infusion to more than 20 000 pg/ml at the highest. Suppression of prolactin secretion was seen in some patients even at the lowest rate of infusion (0.01 microgram/kg/min); marked suppression of prolactin secretion (60%; 17--83%) was found at the intermediate dose (0.1 microgram/kg/min) in 11 of the 12 subjects with little further decrease in serum prolactin (70%; 50--87%) in those in whom the rate of dopamine infusion was increased ten-fold. One patient with the highest serum prolactin (82 500 mu/l) showed no decrease in prolactin either at the lowest or intermediate rates of dopamine infusion. Serum prolactin levels returned to values similar to or greater than basal on cessation of dopamine infusion. Infusion of dopamine at doses much lower than previously used in man exposes the pituitary to a concentration of dopamine sufficient to suppress prolactin secretion. These observations have important implications in understanding the pathophysiology of prolactin secretion from the pituitary gland and for future investigations of the control of hormone release by dopamine.