Dynamic accommodation without feedback does not respond to isolated blur cues.

The aim of this study was to determine whether dynamic accommodation responds to isolated blur cues without feedback, and without changes in the distance of the object. Nine healthy subjects aged 21-40years were recruited. Four different aberration patterns were used as stimuli to induce blur with (1) the eye's natural, uncorrected, optical aberrations, (2) all aberrations corrected, (3) spherical aberration only, or (4) astigmatism only. The stimulus was a video animation based on computer-generated images of a monochromatic Maltese cross. Each individual video was generated for each subject off-line, after measuring individual aberrations at different accommodation levels. The video simulated sinusoidal changes in defocus at 0.2Hz. Dynamic images were observed through a 0.8mm pinhole placed at a plane conjugated with the eye's pupil, thus effectively removing potential feedback stemming from accommodation changes. Accommodation responses were measured with a Hartmann-Shack aberrometer for the four different aberration patterns. The results showed that seven out of nine subjects did not respond to any stimuli, whereas the response of the other two subjects was erratic and they seemed to be searching rather than following the stimulus. A significant reduction in average accommodative gain (from 0.52 to 0.11) was obtained when the dioptric demand cue was removed. No statistically significant differences were found among the experimental conditions used. We conclude that aberration related blur does not drive the accommodation response in the absence of feedback from accommodation.

Immediate changes in masticatory mechanosensitivity, mouth opening, and head posture after myofascial techniques in pain-free healthy participants: a randomized controlled trial.

OBJECTIVE: This study aimed to assess the immediate effects on masticatory muscle mechanosensitivity, maximal vertical mouth opening (VMO), and head posture in pain-free healthy participants after intervention with myofascial treatment in the temporalis and masseter muscles. METHODS: A randomized, double-blind study was conducted. The sample group included 48 participants (n=48), with a mean age of 21±2.47 years (18-29). Two subgroups were defined: an intervention group (n=24), who underwent a fascial induction protocol in the masseter and temporalis muscles, and a control group (n=24), who underwent a sham (placebo) intervention. The pressure pain threshold in 2 locations in the masseter (M1, M2) and temporalis (T1, T2) muscles, maximal VMO, and head posture, by means of the craniovertebral angle, were all measured. RESULTS: Significant improvements were observed in the intragroup comparison in the intervention group for the craniovertebral angle with the participant in seated (P<.001; F1,23=16.45, R2=0.41) and standing positions (P=.012, F1,23=7.49, R2=0.24) and for the pressure pain threshold in the masticatory muscles, except for M2 (P=.151; M1: P=.003; F1,23=11.34, R2=0.33; T1: P=.013, F1,23=7.25, R2=0.23; T2: P=.019, F1,23=6.41, R2=0.21). There were no intragroup differences for the VMO (P=.542). Nevertheless, no significant differences were observed in the intergroup analysis in any of the studied variables (P>.05). CONCLUSION: Myofascial induction techniques in the masseter and temporalis muscles show no significant differences in maximal VMO, in the mechanical sensitivity of the masticatory muscles, and in head posture in comparison with a placebo intervention in which the therapist's hands are placed in the temporomandibular joint region without exerting any therapeutic pressure.

Immediate effects of the suboccipital muscle inhibition technique in craniocervical posture and greater occipital nerve mechanosensitivity in subjects with a history of orthodontia use: a randomized trial.

OBJECTIVE: The purpose of this study was to measure the immediate differences in craniocervical posture and pressure pain threshold of the greater occipital (GO) nerve in asymptomatic subjects with a history of having used orthodontics, after intervention by a suboccipital muscle inhibition (SMI) technique. METHODS: This was a randomized, single-blind, clinical study with a sample of 24 subjects (21±1.78 years) that were divided into an experimental group (n=12) who underwent the SMI technique and a sham group (n=12) who underwent a sham (placebo) intervention. The sitting and standing craniovertebral angle and the pressure pain threshold of the GO nerve in both hemispheres were measured. RESULTS: The between-group comparison of the sample indicated that individuals subjected to the SMI technique showed a statistically significant increase in the craniovertebral angle in both the sitting (P<.001, F1,22=102.09, R2=0.82) and the standing (P<.001, F1,22=21.42, R2=0.56) positions and in the GO nerve pressure pain threshold in the nondominant hemisphere (P=.014, F1,22=7.06, R2=0.24). There were no statistically significant differences observed for the GO nerve mechanosensitivity in the dominant side (P=.202). CONCLUSION: Suboccipital muscle inhibition technique immediately improved the position of the head with the subject seated and standing, the clinical effect size being large in the former case. It also immediately decreased the mechanosensitivity of the GO nerve in the nondominant hemisphere, although the effect size was small.

Safety and feasibility of percutaneous retrograde coronary sinus delivery of autologous bone marrow mononuclear cell transplantation in patients with chronic refractory angina.

BACKGROUND: Chronic refractory angina is a challenging clinical problem with limited treatment options. The results of early cardiovascular stem cell trials using ABMMC have been promising but have utilized intracoronary or intramyocardial delivery. The goal of the study was to evaluate the safety and early efficacy of autologous bone marrow derived mononuclear cells (ABMMC) delivered via percutaneous retrograde coronary sinus perfusion (PRCSP) to treat chronic refractory angina (CRA). METHODS: From May 2005 to October 2006, 14 patients, age 68 +/- 20 years old, with CRA and ischemic stress-induced myocardial segments assessed by SPECT received a median 8.19*10(8) ± 4.3*10(8) mononuclear and 1.65*10(7) ± 1.42*10(7) CD34(+) cells by PRCSP. RESULTS: ABMMC delivery was successful in all patients with no arrhythmias, elevated cardiac enzymes or complications related to the delivery. All but one patient improved by at least one Canadian Cardiovascular Society class at 2 year follow-up compared to baseline (p < 0.001). The median baseline area of ischemic myocardium by SPECT of 38.2% was reduced to 26.5% at one year and 23.5% at two years (p = 0.001). The median rest left ventricular ejection fraction by SPECT at baseline was 31.2% and improved to 35.5% at 2 year follow up (p = 0.019). CONCLUSIONS: PRCSP should be considered as an alternative method of delivery for cell therapy with the ability to safely deliver large number of cells regardless of coronary anatomy, valvular disease or myocardial dysfunction. The clinical improvement in angina, myocardial perfusion and function in this phase 1 study is encouraging and needs to be confirmed in randomized placebo controlled trials.