A Behavioral Economic Approach to Improving Human Papillomavirus Vaccination.

PURPOSE: The objectives of this study were to measure the impact of a behavioral economic intervention on human papillomavirus (HPV) vaccine initiation and series completion rates for adolescents and to measure the impact of the intervention on the receipt of a nonincentivized influenza vaccine. METHODS: We conducted a quasi-randomized trial to compare the impact of an escalating delayed cash incentive (intervention), compared with usual care (control), on HPV vaccination initiation and series completion rates among adolescents (11-17 years) at an urban medical center. We measured HPV vaccine initiation and completion rates during the 12 months after enrollment and subsequent influenza vaccination rates for 24 months after enrollment. RESULTS: A total of 85 participants were actively enrolled in the intervention arm and 103 were passively enrolled in the control arm. Participants were predominantly publically insured African-American and Hispanic adolescents. The majority (75%) of the intervention group received one or more doses of the HPV vaccine, with 36% completing the three-dose series, compared with 47% of the control group receiving one or more doses and only 13% completing the series. The odds of HPV p-value vaccine initiation (odds ratio 4.19 [95% confidence interval 1.84-10.10], p < .01) and HPV vaccine series completion (OR 4.16 [95% confidence interval 1.64-11.28], p < .01) were greater among the intervention group compared with the control group. There was no difference in influenza vaccination rates between the intervention group and the control group during the 2013-2014 season (p = .138) and during the 2014-2015 influenza season (p value .683). CONCLUSIONS: An incentive-based approach to HPV vaccination was effective in increasing vaccine initiation and series dose completion.

Effect of resistance training on neuromuscular junctions of young and aged muscles featuring different recruitment patterns.

To examine the effects of aging on neuromuscular adaptations to resistance training (i.e., weight lifting), young (9 months of age) and aged (20 months of age) male rats either participated in a 7-week ladder climbing protocol with additional weight attached to their tails or served as controls (n = 10/group). At the conclusion, rats were euthanized and hindlimb muscles were quickly removed and frozen for later analysis. Longitudinal sections of the soleus and plantaris muscles were collected, and pre- and postsynaptic features of neuromuscular junctions (NMJs) were visualized with immunofluorescence staining procedures. Cross-sections of the same muscles were histochemically stained to determine myofiber profiles (fiber type and size). Statistical analysis was by two-way ANOVA (main effects of age and treatment) with significance set at P ≤ 0.05. Results revealed that training-induced remodeling of NMJs was evident only at the postsynaptic endplate region of soleus fast-twitch myofibers. In contrast, aging was associated with pre- and postsynaptic remodeling in fast- and slow-twitch myofibers of the plantaris. Although both the soleus and the plantaris muscles failed to display either training or aging-related alterations in myofiber size, aged plantaris muscles exhibited an increased expression of type I (slow-twitch) myofibers in conjunction with a reduced percentage of type II (fast-twitch) myofibers, suggesting early stages of sarcopenia. These data demonstrate the high degree of specificity of synaptic modifications made in response to exercise and aging and that the sparsely recruited plantaris is more vulnerable to the effects of aging than the more frequently recruited soleus muscle.

Presynaptic to postsynaptic relationships of the neuromuscular junction are held constant across age and muscle fiber type.

The neuromuscular junction (NMJ) displays considerable morphological plasticity as a result of differences in activity level, as well as aging. This is true of both presynaptic and postsynaptic components of the NMJ. Yet, despite these variations in NMJ structure, proper presynaptic to postsynaptic coupling must be maintained in order for effective cell-to-cell communication to occur. Here, we examined the NMJs of muscles with different activity profiles (soleus and EDL), on both slow- and fast-twitch fibers in those muscles, and among young adult and aged animals. We used immunofluorescent techniques to stain nerve terminal branching, presynaptic vesicles, postsynaptic receptors, as well as fast/slow myosin heavy chain. Confocal microscopy was used to capture images of NMJs for later quantitative analysis. Data were subjected to a two-way ANOVA (main effects for myofiber type and age), and in the event of a significant (p < 0.05) F ratio, a post hoc analysis was performed to identify pairwise differences. Results showed that the NMJs of different myofiber types routinely displayed differences in presynaptic and postsynaptic morphology (although the effect on NMJ size was reversed in the soleus and the EDL), but presynaptic to postsynaptic relationships were tightly maintained. Moreover, the ratio of presynaptic vesicles relative to nerve terminal branch length also was similar despite differences in muscles, their fiber type, and age. Thus, in the face of considerable overall structural differences of the NMJ, presynaptic to postsynaptic coupling remains constant, as does the relationship between presynaptic vesicles and the nerve terminal branches that support them.

The effects of pre-habilitative conditioning on unloading-induced adaptations in young and aged neuromuscular systems.

The capacity of pre-habilitative conditioning - exercise performed a priori - to mitigate neuromuscular maladaptations to disuse is unclear. This study evaluated pre-habilitation by examining neuromuscular junctions (NMJs) and the myofibers they innervate in young adult and aged muscles. Within each age category, 40 rats were divided into four treatment groups: 1) control, 2) hindlimb suspended (unloaded), 3) prehabilitative conditioning preceding hindlimb suspension, and 4) pre-habilitative conditioning alone. Cytofluorescent staining was used to visualize NMJs, and histochemical staining to assess myofiber profiles (size and type). Statistical analysis featured 2-way ANOVA with main effects for age and treatment, along with interaction. NMJs consistently revealed significant (P≤0.05) main effects for age, but not treatment, or interaction. Typically, aged NMJs showed elongated nerve terminal branching, and more dispersed post-synaptic clusters of ACh receptors, resulting in reduced post-synaptic area per given length of pre-synaptic branching. Analysis of myofiber profiles showed significant main effects for age, treatment, and their interaction. Aged myofibers were smaller than the young ones and a higher percentage of them were Type I. Aged fibers experienced significantly greater unloading-induced atrophy than the young ones. Pre-habilitative conditioning significantly attenuated unloading-induced atrophy among aged, but not young myofibers. It was also observed that pre-habilitative conditioning alone increased myofiber size among aged, but not young adult muscles. In summary, myofibers were more sensitive than NMJs to the treatment interventions implemented. Although more sensitive to the negative effects of muscle unloading, aged myofibers were also more responsive to the hypertrophic effects of pre-habilitative conditioning.