Nathan D. Moss

A review of quality of life and psychosocial issues in scoliosis.

Study Design. Recent literature regarding the psychological impact of scoliosis was reviewed. Objective. To determine the impact of scoliosis on health-related quality of life (HRQL), psychosocial functioning, and body image to improve patient outcomes. Summary of Background Data. Adolescents and adults with adolescent idiopathic scoliosis have been known to score lower than healthy controls on HRQL measures. However, HRQL instruments may not adequately capture psychological distress experienced by patients. Methods. Research papers concerning HRQL and psychosocial factors in patients with scoliosis were reviewed. Results. Studies of psychosocial health and body image have revealed that functioning in these domains may affect compliance behavior and satisfaction with treatment outcomes among adolescent patients. Psychosocial and body image disturbance is less marked in patients with good social or family functioning, or patients who exercise regularly or are psychologically healthy. Adults with scoliosis generally display fewer psychological problems than adolescents. However, adults with scoliosis may experience psychosocial limitations due to poor physical health or body image disturbance. Support group membership can improve psychosocial health in adults with scoliosis. Conclusions. Adolescent patients with scoliosis may experience psychosocial difficulties, especially while undergoing treatment for scoliosis. Interventions aimed at managing psychosocial or body image disturbances may help to ameliorate the potentially negative impact of scoliosis on these facets of life.

In Vivo Behavior of a Helicobacter pylori SS1 nixA Mutant with Reduced Urease Activity

ABSTRACT Helicobacter pylori mutants devoid of urease activity fail to colonize the gastric mucosa of mice; however, the effect of decreased levels of urease on colonization has not been examined. The nixA gene, required for full urease activity, encodes a cytoplasmic membrane nickel transporter that imports nickel ions and leads to incorporation of nickel ions into apourease. A nixA mutant of the Sydney strain of H. pylori (SS1) was constructed by disruption of the nixA gene with a kanamycin resistance cassette. This mutant retained only half the urease activity of the wild-type (wild-type) SS1 strain. C57BL/6j (n = 75) and BALB/c (n = 75) mice were inoculated independently with the wild-type or the nixA strain. The level and distribution of colonization were assessed by bacterial colony counts and histological grading at 4, 12, and 24 weeks postinfection. Colonization levels of the nixA strain in BALB/c mice were significantly lower compared with SS1 (P = 0.005), while colonization in C57BL/6j mice was similar for both the wild-type and mutant strains. Subtle differences in colonization of the different regions of the stomach, determined by microscopic grading, were observed between wild-type SS1 and the nixA strain in BALB/c mice. On the contrary, when C57BL/6j (n = 35) and BALB/c (n = 35) mice were coinfected with the wild-type and nixA strains simultaneously, the nixA mutant failed to colonize and was outcompeted by the wild-type SS1 strain, which established normal levels of colonization. These results demonstrate the importance of the nixA gene for increasing the fitness of H. pylori for gastric colonization. Since nixA is required for full urease activity, the decreased fitness of the nixA mutant is likely due to reduced urease activity; however, pleiotropic effects of the mutation cannot be completely ruled out.

Psychosocial predictors of the use of enhanced podcasting in student learning

The current study examined the influence of psychosocial constructs, from a theory of planned behavior (TPB) perspective, to predict university students’ (N = 159) use of a newly offered on-line learning tool, enhanced podcasts. Pre-semester, students completed questionnaires assessing the TPB predictors (attitude, subjective norm, perceived behavioral control) related to intended enhanced podcast use until the middle of semester. Mid-semester, students completed similar items relating to podcast use until the end of semester. Self-report measures of podcast use were obtained at the middle and end of semester. At both time points, students’ attitudes predicted their intentions and, at the initial time point, subjective norm also predicted intended podcast use. An examination of the beliefs underlying attitudes, the only construct to predict intentions at both time points, revealed differences between those students higher, rather than lower on intentions to use the podcasts, especially for the perceived educational benefits of podcast use later in the semester. Intentions to use enhanced podcasting only predicted self-reported use in the second half of the semester. Overall, this study identified some of the determinants which should be considered by those aiming to encourage student use of novel on-line educational tools.

Lipopolysaccharide-induced biliary factors enhance invasion of Salmonella enteritidis in a rat model.

ABSTRACT In this study, the role of the hepatobiliary system in the early pathogenesis of Salmonella enteritidis infection was investigated in a rat model. Intravenous (i.v.) challenge with lipopolysaccharide (LPS) has previously been shown to enhance the translocation of normal gut flora. We first confirmed that LPS can similarly promote the invasion of S. enteritidis. Oral infection of outbred Australian Albino Wistar rats with 106to 107 CFU of S. enteritidis led to widespread tissue invasion after days. If animals were similarly challenged after intravenous administration of S. enteritidis LPS (3 to 900 μg/kg of body weight), significant invasion of the livers and mesenteric lymph nodes (MLN) occurred within 24 h, with invasion of the liver increasing in a dose-dependent fashion (P< 0.01). If bile was prevented from reaching the intestine by bile duct ligation or cannulation, bacterial invasion of the liver and MLN was almost totally abrogated (P < 0.001). As i.v. challenge with LPS could induce the delivery of inflammatory mediators into the bile, biliary tumor necrosis factor alpha (TNF-α) concentrations were measured by bioassay. Biliary concentrations of TNF-α rose shortly after LPS challenge, peaked with a mean concentration of 27.0 ng/ml at around 1 h postchallenge, and returned to baseline levels (3.1 ng/ml) after 2.5 h. Although TNF-α cannot be directly implicated in the invasion process, we conclude that the invasiveness of the enteric pathogen S. enteritidis is enhanced by the presence of LPS in the blood and that this enhanced invasion is at least in part a consequence of the delivery of inflammatory mediators to the gastrointestinal tract by the hepatobiliary system.

The biological activity of serum IgE changes over the course of a primary response

Mast‐cell degranulation is triggered by the bridging of Fc receptor‐bound antigen‐specific immunoglobulin IgE on the cell surface. In vitro experiments suggest that antibody affinity and nonspecific IgE may affect the mast‐cell function, however, their importance in vivo is unclear. Investigations of the effects of these parameters on mast‐cell sensitization were therefore carried out in a rat immunization model in which the IgE response is transient and peaks on days 10–15. Between these two timepoints, significant changes in the level of specific IgE were not observed, but the avidity of specific IgE increased (P < 0.05). Total serum IgE peaked on day 10 and slowly declined, with the relative proportion of specific to total IgE increasing from day 10–15 (P < 0.05). Despite similar levels of antigen‐specific IgE, increasing avidity and an increased proportion of specific IgE between days 10 and 15, the biological activity of IgE in the serum peaks on day 10 and declines rapidly, dropping around seven‐fold by day 15 (P < 0.001). Mechanisms that could explain this finding, such as differential expression of IgE isoforms and changes in the fine specificity of the IgE response, are discussed.

Body weight attributions and eating self-efficacy in adolescence.

In an attempt to find an optimum age during adolescence to target weight control programs successfully, 189 adolescents were surveyed using measures of eating self-efficacy and body-weight attributions. The sensitivity of the attribution measures was assessed in a pilot study using 100 adolescents. The major experiment indicated higher levels of eating control at 12 and 13 years of age, decreasing with age. However, the locus of control measure indicated an increase in internal attributions with age. It is argued that this paradox between degree of control subjects reported over their eating and the degree subjects believed their body weight to be controlled internally may have important clinical implications and should be investigated further.

The changing motivations of students’ use of lecture podcasts across a semester: an extended theory of planned behaviour approach

We extended the previous work of Moss, O’Connor and White, to include a measure of group norms within the theory of planned behaviour (TPB), to examine the influences on students’ decisions to use lecture podcasts as part of their learning. Participants (N = 90) completed the extended TPB predictors before semester began (Time 1) and mid-semester (Time 2) and reported on their podcast use at mid-semester (Time 2) and end of semester (Time 3). We found that attitudes and perceived social pressures were important in informing intentions at both time points. At Time 1, perceptions of control over performing the behaviour and, at Time 2, perceptions of whether podcast use was normative among fellow students (group norms) also predicted intended podcast use. Intentions to use podcasting predicted self-reported use at both Time 2 and Time 3. These results provide important applied information for educators to encourage student use of novel on-line educational tools.