Repairing process at the injury site in the transected muscle fibers of the mouse tibialis anterior was studied by light and electron microscopy. Immediately after the transection, the cut end (approximately 10 μm) was filled with dense network of disorganized myofilaments, in which disrupted membranous structures and degraded mitochondria were scattered. In the portion next to the portion exhibiting sudden necrotic changes, morphological features of the myofilaments, mitochondria and membranous structures appeared to be almost normal. The degradation of disorganized myofilaments at the cut end began within 1 hour after the transection, and at 1hour after the transection, the degenerating areas were noted in most of muscle fibers up to 150-250 μm from the cut end. Following the degradation, accumulation of mitochondria occurred between the necrotic and myofilament-predominant living portions, and several transverse tubules (T-tubules) and sarcoplasmic reticula were found between the mitochondria-accumulated and myofilament-predominant areas. In most cases, demarcation membrane formed between the mitochondria-accumulated and myofilament-predominant areas, and the fusion of T-tubules and sarcoplasmic reticula was encountered in these areas, suggesting that at least some parts of the demarcation membranes formed through fusion of T-tubules and sarcoplasmic reticula. This repairing process was completed in a number of muscle fibers within 6 hours after the transection. Macrophages were first found in the injured portions at 6 hours after the transection, increased in number with time, and several macrophages were distributed at 1 to 3 days after the transection. Some spindle-shaped cells were first found in the degenerating portions of the muscle fibers at 1 day after the transection. Since they were located along the basal lamina of the muscle fiber, and had a long oval pale nucleus and relatively abundant cytoplasm, they can be regarded as activated satellite cells. They gradually increased in number with time, and became larger and longer. On and after 5 days, thin regenerating muscle fibers exhibiting centrally located nuclei were observed, and they became gradually thicker with time. These findings indicate that the muscle regeneration was actively occurring during these periods. The repairing process is followed by the invasion of macrophages, and then the occurrence of muscle regeneration in the sequential order. These findings suggest that there might be close chronological relationship among these events.
The objective of this study was to elucidate the characteristics of swallowing disorder in cerebrovascular disease (CVD) patients in terms of newly developed indices for the basic elements of swallowing movement and muscle tone in the neck. A total of 133 patients participated in our study, 116 patients with CVD and 17 elderly patients who had no history of dysphagia and CVD. These patients were divided into 5 groups according to the existence of swallowing disorder and interval from onset. The effects of CVD and swallowing disorder were elucidated by two-group comparison. Measurement items consisted of and passive neck ROM in 4 directions (flexion, extension, lateral flexion, and rotation.) 5 newly developed indices: distance from the genion to the upper end of thyroid cartilage (GT), distance from the upper end of thyroid cartilage to the upper end of sternum (TS), length of the suprahyoid and infrahyoid muscles on neck extension (GT+TS), relative larynx position (GT/(GT+TS)), and strength of the suprahyoid muscles (GS grade). Patients with CVD of less than 90 days' duration exhibited GT shortening, decline in GS grade, and limitations in neck extension and rotation ROM. In the chronic phase, TS shortening, laryngeal lowering, and limitations in neck flexion and lateral flexion ROM were observed. Physical therapists should aim to improve the factors that might impede laryngeal movement and to conduct preparatory exercises that facilitate swallowing movements.
The effect of Vertical Oscillatory Pressure (VOP) on Low Back Pain (LBP) intensity and lumbo-sacral mobility in youths compared to elders was examined. Eighty five male (56) and female (29) subjects comprising 45 youths (18-28 years old) and 42 elders (65-75 years old), including LBP (40) and pain-free individuals participated in the study. Subjects with LBP received VOP on each vertebra from the first lumbar to the sacrum, 10 oscillations in one minute repeated at each vertebra. Pain intensity (measured using Borg's 10 point scale) and mobility were measured at the start, after VOP and five minutes after cryotherapy. Control subjects did not receive VOP and cryotherapy but had their sensory perception and spinal mobility measured at the start, after 15 and 26 minutes respectively. Pain intensity decreased significantly [elders, p<0.01; youths, p<0.05] while the range of forward and side flexions increased significantly (p<0.05) only in elders after VOP. Cryotherapy after VOP therapy did not add any significant effect on pain intensity and trunk mobility. Mobility and perceptual levels of the control subjects did not alter significantly. Pain intensity and flexion (forward and side flexions in elders only) are improved by VOP and should be preferred spinal mobilization therapy outcome measures in youths and elders with LBP respectively.
The aim of this study was to investigate the actual situation of low back pain (LBP) prevention in care workers with questionnaires, and this data were used to clarify and decrease LBP factors. Subjects were 52 care workers (30.7 ± 10.0 years old) in a nursing home who filled out two kinds of questionnaires about LBP, one about the prevalence of LBP (QN1) and the other about LBP control measures (QN2). They had either license of certified care worker, 1st or 2nd class care worker. The data were collected for the purpose of finding differences in age and career (QN1) and differences in LBP control measures (QN2) between subjects with and without LBP. The average career of the subjects was 19.1 ± 12.5 months, and the prevalence of LBP among them was 46.2% (24 care workers), of which 66.7% began having LBP after starting work as care workers. Moreover, 75.0% of these subjects began having LBP within a year after starting work. Further, of the 24 care workers with LBP, 66.7% reported constantly experiencing LBP. The major risk factors given for LBP in care work were transfer, the replacement of diapers, and movement in a half-sitting posture. Compared with LBP subjects, rates of taking preventative steps in the non-LBP group were low. More than 80% of the subjects with LBP engaged in prevention methods such as using body mechanics, learning the proper way to perform care activities, using LBP support belts, and increasing their skills and knowledge with regard to their job responsibilities. Most subjects began to engage in such prevention methods after the onset of LBP. The results of this investigation indicated that most subjects did not engage in measures to counter their LBP until after it had already started, and that they selected prevention methods which were easy to perform and effective. It is important for care workers to learn the best ways to inhibit pain and prevent the occurrence, or recurrence, of LBP. It is necessary for physical therapists to grasp the actual situation of LBP prevention as an occupational disease and to educate this.