Experimental muscle pain results in reorganization of coordination among trapezius muscle subdivisions during repetitive shoulder flexion

The aim of the study was to examine the effect of experimental unilateral upper trapezius muscle pain on the relative activation of trapezius muscle subdivisions bilaterally during repetitive movement of the upper limb. Surface EMG signals were detected from nine healthy subjects from the upper, middle and lower divisions of trapezius during a repetitive bilateral shoulder flexion task. Measurements were performed before and after injection of 0.5 ml hypertonic (pain condition) and isotonic (control) saline into the upper division of the right trapezius muscle in two experimental sessions. On the painful side, upper trapezius showed decreased EMG amplitude (average rectified value, ARV) and lower trapezius increased ARV throughout the entire task following the injection of hypertonic saline (40.0 ± 22.2 vs. 26.0 ± 17.4 μV, and 12.5 ± 7.6 vs. 25.6 ± 14.8 μV, respectively, at the beginning of the contraction). On the side contralateral to pain, greater estimates of ARV were identified for the upper division of trapezius as the task progressed (37.4 ± 20.2 vs. 52.7 ± 28.4 μV, at the end of the contraction). Muscle fiber conduction velocity did not change with pain in all three divisions of the right trapezius muscle. The results suggest that local elicitation of nociceptive afferents in the upper division of the trapezius induces reorganization in the coordinated activity of the three subdivisions of the trapezius in repetitive dynamic tasks.     

Dietary Supplement Use in a Large,Representative Sample of the US Armed Forces

Background

Dietary supplement (DS) use is prevalent among the US Armed Forces personnel, but representative cross-service comparisons and characteristics of personnel using DSs are limited.

TGF alpha has low protein expression in nonsyndromic clefts

Genetic studies have demonstrated that nonsyndromic cleft is composed of two separate entities: the cleft palate only and cleft of the lip, alveolus with or without cleft palate; both have a heterogeneous genetic background and environmental factors contribute to the onset of these malformations. The role of transforming growth factor alpha (TGF-A) was considered possible, but conflicting results have been reported. To detect if TGF-A is involved in the onset of cleft diseases, a series of patients with nonsyndromic clefts and control subjects were analyzed with regard to protein expression. Forty-three patients with nonsyndromic clefts and 21 unaffected subjects were enrolled in this study. Paraffin-embedded specimens were matched with TGF-A antibody and then scanned with a computerized image analyzer. TGF-A was scored as absent, moderately (from 10% to 30%), and highly expressed in epithelium, gland, and muscle. Data were statistically analyzed with a Kruskal-Wallis test. Comparison between control subjects and patients with clefts showed that only gland and epithelium reached a significant P value. A subsequent comparison between cleft of the lip, alveolus with or without cleft palate and cleft palate only groups demonstrated a statistically significant difference only for gland. TGF-A was decreasingly expressed in unaffected, cleft of the lip, alveolus with or without cleft palate, and patient with cleft palate only and thus further strength has been given to its role in the onset of the disease.     

Antigen-induced mediator release in primates.

We examined the release of bronchoactive mediators into the airways of allergic primates during the acute response to specific antigen inhalation. Twelve adult male cynomolgus monkeys (Macaca fascicularis) with a naturally occurring respiratory sensitivity to inhaled Ascaris suum extract were anesthetized and intubated for each study. Respiratory system resistance (Rrs) and dynamic lung compliance (CLdyn) were measured before and after antigen inhalation, and the release of mediators into the airways was assessed by bronchoalveolar lavage (BAL). BAL samples were concentrated approximately 5-fold before quantitation of LTC4 and PGD2 by RP-HPLC and radioimmunoassay and histamine by a fluorometric assay. Antigen inhalation resulted in a 40-fold increase in BAL levels of i-LTC4 (1.5 +/- 0.7 to 41.6 +/- 12.7 ng, p less than 0.01), a 10-fold increase in i-PGD2 (2.4 +/- 0.9 to 25.9 +/- 5.5 ng, p less than 0.01), and a 20-fold increase in BAL histamine (1.0 +/- 1.5 to 21.4 +/- 2.3 micrograms, p less than 0.01). Dexamethasone (n = 7) inhibited the antigen-induced increase in BAL i-LTC4 (71 +/- 6%, p less than 0.01) and i-PGD2 (52 +/- 8%, p less than 0.05) while weakly inhibiting histamine release (43 +/- 10%). Indomethacin (n = 7) had a variable effect on i-LTC4 levels (6 +/- 51%), strongly inhibited i-PGD2 (88 +/- 9%, p less than 0.01), and had no effect on histamine release (25 +/- 8%). Pretreatment with iodoxamide tromethamine significantly blocked the release of each mediator, but mepyramine, an H1 antagonist, had no effect on mediator release.(ABSTRACT TRUNCATED AT 250 WORDS)     

Substantia nigra in Parkinson’s disease: a multimodal MRI comparison between early and advanced stages of the disease

This study focused on the substantia nigra (SN) in Parkinson’s disease (PD). We measured its area and volume, mean diffusivity (MD), fractional anisotropy (FA) and iron concentration in early and late PD and correlated the values with clinical scores. Twenty-two early PD (EPD), 20 late PD (LPD) and 20 healthy subjects (age 64.7 ± 4.9, 60.5 ± 6.1, and 61 ± 7.2 years, respectively) underwent 1.5 T MR imaging with double-TI-IR T1-weighted, T2*-weighted and diffusion tensor imaging scans. Relative SN area, MD, FA and R2* were measured in ROIs traced on SN. Correlation with Unified Parkinson Disease Rating Scale (UPDRS) scores was assessed. In LPD, the SN area was significantly reduced with respect to EPD (p = 0.04) and control subjects (p < 0.001). In EPD, the SN area was also significantly smaller than in controls (p = 0.006). Similarly, the SN volume significantly differed between LPD and controls (p = 0.001) and between EPD and LPD (p = 0.049), while no significant differences were found between controls and EPD. Both SN area (r = 0.47, p = 0.004) and volume (r = 0.46, p = 0.005) correlated with UPDRS scores. At 1.5 T, SN morphological measurements were sensitive to early PD changes and able to track the disease progression, while MD and FA measures and relaxometry did not provide significant results.     

Memories of attachment hamper EEG cortical connectivity in dissociative patients

In this study, we evaluated cortical connectivity modifications by electroencephalography (EEG) lagged coherence analysis, in subjects with dissociative disorders and in controls, after retrieval of attachment memories. We asked thirteen patients with dissociative disorders and thirteen age- and sex-matched healthy controls to retrieve personal attachment-related autobiographical memories through adult attachment interviews (AAI). EEG was recorded in the closed eyes resting state before and after the AAI. EEG lagged coherence before and after AAI was compared in all subjects. In the control group, memories of attachment promoted a widespread increase in EEG connectivity, in particular in the high-frequency EEG bands. Compared to controls, dissociative patients did not show an increase in EEG connectivity after the AAI. Conclusions: These results shed light on the neurophysiology of the disintegrative effect of retrieval of traumatic attachment memories in dissociative patients.