Understanding Students’ Cognitive and Affective Attitude and Attitudinal Structures Toward Physical Activity: A Person-Centered Approach

Objectives: The purpose of this study was to determine the proportions of students who were holding positive, negative, and neutral cognitive/affective attitude and different cognitive-affective attitudinal structures toward moderate-to-vigorous physical activity (MVPA) using a person-centered approach. Methods: A total of 3949 students participated in this study (1065 middle-school students, 784 high-school students, and 2100 college students). Results: A majority of students were holding positive cognitive (about 94%) and affective attitude (about 85%) toward MVPA. Most students (about 84%) held the Positive cognitive—Positive affective attitudinal structure toward MVPA. School level influenced the proportions of students who were holding different cognitive attitude status, affective attitude status, and cognitive-affective attitudinal structures; gender and body weight status did not significantly influence them. Conclusions: This study furthers our understandings on students’ attitude and attitudinal structures toward PA. It lays the foundation for the development of physical education curriculum or PA programs that aim at promoting students’ PA behavior through changing their PA attitude. Future studies are needed to examine the effects of different attitude statuses and attitudinal structures on PA behavior

Attitude and Attitudinal Structures Toward Physical Education and Their Influences on Physical Activity Behavior

Objectives: The purpose of this study was to examine middle and high school students’ cognitive and affective attitude and their cognitive-affective attitudinal structures toward physical education (PE). The effects of cognitive and affective attitude and attitudinal structures on physical activity (PA) in PE and outside of school were also examined. Methods: 1773 Chinese middle and high-school students participated in this study. SEM, Chi-square test, ANOVAs, and Contingency tables were adopted to address the research questions. Results: The results showed that most students (\u3e90%) were holding positive cognitive and affective attitude toward PE. Students’ affective attitude significantly influences their PA in PE and outside of school. Most students were holding the positive cognitive-positive negative attitudinal structure toward PE. Conclusions: All these findings lay important foundations for future theoretical advancement about attitude toward PE and provide guidance for PE teachers on attitude intervention and PA promotion

Genomic Characterization and High Prevalence of Bocaviruses in Swine

Using random PCR amplification followed by plasmid subcloning and DNA sequencing, we detected bocavirus related sequences in 9 out of 17 porcine stool samples. Using primer walking, we sequenced the nearly complete genomes of two highly divergent bocaviruses we provisionally named porcine bocavirus 1 isolate H18 (PBoV1-H18) and porcine bocavirus 2 isolate A6 (PBoV2-A6) which differed by 51.8% in their NS1 protein. Phylogenetic analysis indicated that PBoV1-H18 was very closely related to a ∼2 Kb central region of a porcine bocavirus-like virus (PBo-LikeV) from Sweden described in 2009. PBoV2-A6 was very closely related to the porcine bocavirus genomes PBoV-1 and PBoV2 from China described in 2010. Among 340 fecal samples collected from different age, asymptomatic swine in five Chinese provinces, the prevalence of PBoV1-H18 and PBoV2-A6 related viruses were 45–75% and 55–70% respectively, with 30–47% of pigs co-infected. PBoV1-A6 related strains were highly conserved, while PBoV2-H18 related strains were more diverse, grouping into two genotypes corresponding to the previously described PBoV1 and PBoV2. Together with the recently described partial bocavirus genomes labeled V6 and V7, a total of three major porcine bocavirus clades have therefore been described to date. Further studies will be required to elucidate the possible pathogenic impact of these diverse bocaviruses either alone or in combination with other porcine viruses

Little or no ability of obestatin to interact with ghrelin or modify motility in the rat gastrointestinal tract

Background: Several peptides derived from the gastrointestinal tract (GI) have been shown to have profound effects on GI motility, food intake and metabolism. Two such peptides, derived from the same prohormone, are the peptides ghrelin and obestatin, discovered in 1999 and 2005, respectively. The ghrelin receptor (GHS-R) is distributed in a large number of central and peripheral tissues, such as, the GI tract, pancreas, kidney, fat, skeletal muscle and several parts of the brain. The obestatin receptor still remains unknown. Two major molecular forms of ghrelin, acyl and desacyl ghrelin exist. They regulate GI motility peripherally in the local enteric nervous system, but also by activating hypothalamic peptides via the vagal nerve or the bloodstream by crossing the blood-brain barrier (BBB). Ghrelin is involved in a variety of metabolic functions by affecting the glucose homeostasis, fat metabolism, appetite and meal initiation. The role of obestatin and its interaction with ghrelin is still uncertain. Aims: The main aims of this thesis were to investigate the role of obestatin and ghrelin in GI motility in vitro and in vivo in rodents and man. Material and methods: Gastric emptying and small bowel motility were studied in vivo in rats with implanted gastric catheter and intestinal electrodes. Gastric emptying, oro-caecal transit, colonic transit and gut peptides were assessed in man. Ghrelin, obestatin or saline was infused in rats. Ghrelin or saline was infused in normal humans for 6 hours. In vitro studies with human GI tissue were also performed. Gastric emptying was studied in patients randomised to 3 hours saline or ghrelin infusion, before and day 2 after open colo-rectal surgery. Gastric emptying and changes in serum levels of GI peptide hormones were studied in obese subjects subjected to a liquid meal with acetaminophen before, 3 days, 2 months and 1 year after Roux-en-Y gastric bypass (RYGB) surgery. Results: Whereas ghrelin stimulated GI motility, obestatin did not affect motility in vitro or in vivo in rats. Ghrelin increased gastric emptying in healthy humans and in patients after colo-rectal surgery. There was no effect on small bowel or colonic transit in healthy humans, but time to defecation was shorter when ghrelin was administered after colo-rectal surgery. Post-prandial elevations of glucose, insulin and GLP-1 occurred earlier and were higher with ghrelin in healthy humans. Plasma concentrations of ghrelin were unchanged after RYGB. Gastric (pouch) emptying was twice as fast after RYGB compared to before surgery. There was a progressive increase in several GI peptides after RYGB over 1 year after surgery. Conclusions: In rodents ghrelin stimulates GI motility but obestatin has no effect. Ghrelin potently stimulates gastric emptying in healthy humans and in patients after surgery, while stimulation of intestinal motility seems more outspoken after surgery. In contrast to other studies plasma ghrelin was only significantly different on day 3 and thereafter not different after RYGB. Even if exogenous ghrelin can stimulate motility, endogenous ghrelin does not change after surgery and is less likely to modulate GI motility, transit or glucose metabolism after RYGB. However, early changes of other GI peptides (e.g. glucagon-like peptide-1) after RYGB likely contribute to the improved glucose homeostasis post surgery