Age-related physiological and morphological changes of muscle spindles were examined in rats (male Fischer 344/DuCrj: young, 4-13 months; middle-aged, 20-22 months; old, 28-31 months). Single afferent discharges of the muscle spindles in gastrocnemius muscles were recorded from a finely split dorsal root during ramp-and-hold (amplitude, 2.0 mm; velocity, 2-20 mm s −1 ) or sinusoidal stretch (amplitude, 0.05-1.0 mm; frequency, 0.5-2 Hz). Respective conduction velocities (CVs) were then measured. After electrophysiological experimentation, the muscles were dissected. The silver-impregnated muscle spindles were teased and then analysed using a light microscope. The CV and dynamic response to ramp-and-hold stretch of many endings were widely overlapped in old rats because of the decreased CV and dynamic response of primary endings. Many units in old rats showed slowing of discharge during the release phase under ramp-and-hold stretch and continuous discharge under sinusoidal stretch, similarly to secondary endings in young and middle-aged rats. Morphological studies revealed that primary endings of aged rat muscle spindles were less spiral or non-spiral in appearance, but secondary endings appeared unchanged. These results suggest first that primary muscle spindles in old rats are indistinguishable from secondary endings when determined solely by previously used physiological criteria. Secondly, these physiological results reflect drastic age-related morphological changes in spindle primary endings.

If not properly regulated, the large amount of reafferent sensory signals generated by our own movement could destabilize the CNS. We investigated how input from peripheral nerves to spinal cord is modulated during behavior. We chronically stimulated the deep radial nerve (DR; proprioceptive, wrist extensors), the median nerve (M; mixed, wrist flexors and palmar skin) and the superficial radial nerve (SR; cutaneous, hand dorsum) while four monkeys performed a delayed wrist flexion-extension task. Spinal neurons putatively receiving direct sensory input were defined based on their evoked response latency following nerve stimulation. We compared the influence of behavior on the evoked response (responsiveness to a specific peripheral input) and firing rate of 128 neuron-nerve pairs based on their source nerve. Firing rate increased during movement regardless of source nerve, whereas evoked response modulation was strikingly nerve-dependent. In SR ( = 47) and M ( = 27) neurons (cutaneous or mixed input), the evoked response was suppressed during wrist flexion and extension. In contrast, in DR neurons ( = 54, pure proprioceptive input), the evoked response was facilitated exclusively during movements corresponding to the contraction of DR spindle-bearing muscles (i.e., wrist extension). Furthermore, modulations of firing rate and evoked response were uncorrelated in SR and M neurons, whereas they tended to be positively comodulated in DR neurons. Our results suggest that proprioceptive and cutaneous inputs to the spinal cord are modulated differently during voluntary movements, suggesting a refined gating mechanism of sensory signals according to behavior. Voluntary movements produce copious sensory signals, which may overwhelm the CNS if not properly regulated. This regulation is called "gating" and occurs at several levels of the CNS. To evaluate the specificity of sensory gating, we investigated how different sources of somatosensory inputs to the spinal cord were modulated while monkeys performed wrist movements. We recorded activity from spinal neurons that putatively received direct connections from peripheral nerves while stimulating their source nerves, and measured the evoked responses. Whereas cutaneous inputs were suppressed regardless of the type of movement, muscular inputs were specifically facilitated during relevant movements. We conclude that, even at the spinal level, sensory gating is a refined and input-specific process.

The purpose of this study was to investigate effects of long-term participation to swimming on adaptations of spinal reflex excitability. To this end, mechanically induced stretch reflex (SR) and electrically induced Hoffmann (H-) reflex of the soleus muscle were investigated between swimmers with experience of more than 10 years and non-trained individuals while sitting at rest. The amplitude and the gain (stretch velocity vs. amplitude of the reflex response) of the SR were significantly greater in the swimming group than in the non-trained control group. Similarly, the responses of the H-reflex were also significantly greater in the swimming group than in the non-trained control group. Results of this study demonstrated that the spinal reflex excitability in experienced swimmers was far more enhanced than in non-trained individuals.

Carotid ultrasound is an imaging modality that allows non-invasive assessment of vascular anatomy and function. Carotid intima-media thickness (IMT) has been shown to predict cardiovascular (CV) risk in multiple large studies. However, in 2013, American College of Cardiology/American Heart Association guidelines designated that the carotid IMT as class III evidence level was not recommended for use in clinical practice as a routine measurement of risk assessment for a first atherosclerotic CV event. Following the announcement of this guideline, combined common carotid IMT and plaque, including plaque tissue characterization and plaque burden, using 3D ultrasound was reported to be better than either measurement alone in a variety of studies. Moreover, changes in the intima thickness were related to aging and early atherosclerosis, and remodeling of the media thickness was associated with hypertension. Separate measurement is useful for evaluating the effects of different atherosclerotic risk factors on the arterial wall; however, a more detailed and elaborate technique needs to be developed. If so, separate measurement will play an important role in the assessment of atherosclerosis and arterial wall change according to a variety of risk factors, such as metabolic syndrome. In addition, although carotid blood flow velocity is a useful tool for risk classification and prediction in clinical practice, further clinical research is needed. The value of carotid IMT by ultrasound examination for risk stratification remains controversial, and groups developing future guidelines should consider the roles of plaque presence and burden and hemodynamic parameters in additional risk stratification beyond carotid IMT in clinical practice.

It is known that in advanced hypertensive retinopathy, which changes advanced hypertensive retinopathy (Grade III or IV), there is a strong relation between retinal microvascular lesions and cardiac and macrovascular markers of target organ damage (TOD). The prevalence of grade II hypertensive retinopathy and its relationship to cardiovascular risk factors remain controversial. The subjects, a total of 437 hypertensive patients, were divided into three groups according to modified Keith, Wagener, and Barker (KWB) classification by two ophthalmologists: Grade 0 with normal retinal change (N = 169, 38.7%), Grade I with arteriolar narrowing (N = 215, 49.1%), Grade II with arteriovenous crossings (N = 49, 11.2%). The prevalence of Grade I and Grade II hypertensive retinopathy was significantly higher than that of advanced hypertensive retinopathy. The grade of hypertensive retinopathy was related to age, duration of hypertension, coronary artery disease (CAD), and left ventricular hypertrophy (LVH). The prevalence of LVH and CAD in Grade II was significantly higher than in Grade I and Grade 0. The hypertensive retinopathy Grade II was significantly correlated with LVH (odds ratio (OR) 2.3, 95% confidence interval (CI) 1.21-4.44, p < 0.05) and CAD (OR 4.2, 95% CI 1.97-8.95, p-<-0.001). Grade I and Grade II hypertensive retinopathy are frequently observed in hypertensive patients compared to Grade III and IV patients. We concluded that Grade II hypertensive retinopathy is closely related to CAD and should therefore not be ignored.

The present study showed that nonvalidated devices are used widely in clinical practice and a substantial portion is inaccurate. Therefore, recommendation of validated devices should be the first step. Furthermore, all devices need to be examined for accuracy before use irrespective of their validation status.

Background: Strain analysis is feasible using three-dimensional (3D) echocardiography. This approach provides various parameters based on speckle tracking analysis from one full-volume image of the left ventricle; however, evidence for its volume independence is still lacking. Methods: Fifty-eight subjects who were examined by transthoracic echocardiography immediately before and after hemodialysis (HD) were enrolled. Real-time full-volume 3D echocardiographic images were acquired and analyzed using dedicated software. Two-dimensional (2D) longitudinal strain (LS) was also measured for comparison with 3D strain values. Results: Longitudinal (pre-HD: −24.57 ± 2.51, post-HD: −21.42 ± 2.15, P < 0.001); circumferential (pre-HD: −33. 35 ± 3.50, post-HD: −30.90 ± 3.22, P < 0.001); and radial strain (pre-HD: 46.47 ± 4.27, post-HD: 42.90 ± 3.61, P < 0. 001) values were significantly decreased after HD. The values of 3D principal strain (PS), a unique parameter of 3D images, were affected by acute preload changes (pre-HD: −38.10 ± 3.71, post-HD: −35.33 ± 3.22, P < 0.001). Twist and torsion values were decreased after HD (pre-HD: 17.69 ± 7.80, post-HD: 13.34 ± 6.92, P < 0.001; and pre-HD: 2.04 ± 0.86, post-HD:1.59 ± 0.80, respectively, P < 0.001). The 2D LS values correlated with the 3D LS and PS values. Conclusion: Various parameters representing left ventricular mechanics were easily acquired from 3D echocardiographic images; however, like conventional parameters, they were affected by acute preload changes. Therefore, strain values from 3D echocardiography should be interpreted with caution while considering the preload conditions of the patients.

Fabry disease (FD) is a progressive, X-linked lysosomal storage disorder caused by a deficiency of α-galactosidase A activity. Affected individuals accumulate globotriaosylceramide and glycosphingolipids in the lysosomes and cytoplasm of cells throughout the body, leading to major organ failure and premature death. Cardiac involvement includes left ventricular hypertrophy, arrhythmia, endothelial dysfunction at vascular wall, and cardiomyopathy. The diagnosis of FD can be difficult and there is often a long lag time between symptoms and diagnosis. Here, we present a case of a 50-year-old woman with typical Fabry disease who showed serial electrocardiographic and echocardiographic changes over 17 years prior to diagnosis with Fabry disease.