Increased levels of substance P in patients taking beta-blockers are linked with a protective effect on oropharyngeal dysphagia.

BACKGROUND: We have recently found a potential protective effect of beta-blockers on oropharyngeal dysphagia (OD). The action mechanism by which beta-blockers could wield this protective effect is unknown, but the neurotransmitter substance P (SP) could play a key role. The aim of this study was to analyze serum and saliva SP levels in patients taking beta-blockers (TBB), and to explore its relationship with OD. METHODS: Adult (>50 year) patients TBB were randomly recruited from the primary care setting and 1:1 matched by age, sex, and Barthel Index (BI) with patients not taking beta-blockers (NTBB). Serum and saliva samples were taken and analyzed for their SP levels using an enzyme-linked immunosorbent assay (ELISA). Socio-demographic and clinical variables were collected. Dysphagia was evaluated in all patients using the clinical volume-viscosity swallow test (V-VST). KEY RESULTS: We studied 28 patients TBB (64.96 ± 7.31 years, 57.1% women, BI 99.6 ± 1.31, carvedilol-equivalent dose 24.11 ± 18.12 mg) and 28 patients NTBB (65.61 ± 6.43 years, 57.1% women, BI 99.6 ± 1.31). SP serum levels were significantly higher in patients TBB (260.68 ± 144.27 vs 175.46 ± 108.36 pg/mL, P = .009) as were SP saliva levels (170.34 ± 146.48 vs 102.73 ± 52.28 pg/mL, P < .001) compared with patients NTBB. The prevalence of OD was 32.1% in patients TBB and 67.9% in patients NTBB (P = .015). Moreover, patients with OD had significantly lower SP saliva levels in comparison with patients without clinical signs of OD (98.39 ± 43.25 vs 174.69 ± 147.21 pg/mL) P < .001. CONCLUSIONS & INFERENCES: We have found that serum and saliva SP levels are greater in patients TBB. This increase in SP levels could be the action mechanism by which beta-blockers protect patients from OD.

Tendinopathy discrimination by use of spatial frequency parameters in ultrasound B-mode images.

The structural characteristics of a healthy tendon are related to the anisotropic speckle patterns observed in ultrasonic images. This speckle orientation is disrupted upon damage to the tendon structure as observed in patients with tendinopathy. Quantification of the structural appearance of tendon shows promise in creating a tool for diagnosing, prognosing, or measuring changes in tendon organization over time. The current work describes a first step taken towards this goal-classification of Achilles tendon images into tendinopathy and control categories. Eight spatial frequency parameters were extracted from regions of interest on tendon images, filtered and classified using linear discriminant analysis. Resulting algorithms had better than 80% accuracy in categorizing tendon image kernels as tendinopathy or control. Tendon images categorized wrongly provided for an interesting clinical association between incorrect classification of tendinopathy kernels as control and the symptom and clinical time history based inclusion criteria. To assess intersession reliability of image acquisition, the first 10 subjects were imaged twice during separate sessions. Test-retest of repeated measures was excellent (tau = 0.996, ICC = (2, 1) = 0.73 with one outlier) indicating a general consistency in imaging techniques.