Yasuyuki Matsushima

Blood Pressure-Lowering Effects of Lifestyle Modification: Possible Involvement of Nitric Oxide Bioavailability

Lifestyle modification is recommended as a non-pharmacological approach to treatment of hypertension. Many investigators have reported that exercise has antihypertensive effects, and various mechanisms have been proposed to explain this phenomenon. For example, nitric oxide (NO), which may be increased by exercise, has been reported to play a crucial role in preserving vessel homeostasis both by regulating vascular tone and by exerting anti-atherosclerotic effects. NO is known to be exquisitely sensitive to inactivation by superoxide radicals. However, the relationship between the blood pressure-lowering effect of lifestyle modification and NO bioavailability remains unknown. We investigated the effects of a 12-week lifestyle modification program consisting of mild exercise and diet on changes in blood pressure, plasma nitrate/nitrite (NOx), plasma nitrotyrosine, which is the footprint of NO interaction with reactive oxygen species, and plasma extracellular-superoxide dismutase (EC-SOD). The 12-week lifestyle modification program lowered blood pressure and increased plasma NOx. When the subjects were divided into two groups according to the change of plasma nitrotyrosine as an indicator of NO bioavailability, the subjects whose plasma nitrotyrosine decreased exhibited a significant relationship between the blood pressure-lowering effect of the lifestyle modification and the increase in EC-SOD, whereas those without a decrease in plasma nitrotyrosine exhibited a significant relationship between the blood pressure-lowering effect and the increase in maximum oxygen consumption. These results indicate that the level of NO bioavailability influences the mechanism of the blood pressure-lowering effect of aerobic exercise and diet.

Texture, sensory and swallowing characteristics of high-pressure-heat-treated pork meat gel as a dysphagia diet

To develop a soft meat product for a dysphagia diet, high-pressure technology was applied. Pressure-heat-treated ground pork meat (PH) was prepared from ground pork mixed with water (ground meat: water, 1:0.5 or 1:1) and salt (1.5%). PH-gels were made from these meat homogenates by treatment at 400 MPa for 20 min, followed by heat treatment. Heat-treated pork meat homogenates (H) were also prepared. The hardness and adhesiveness of the 1:1PH-gel was lower than those of the 1:1H-gel. The PH-gel scored higher in sensory evaluations of elasticity, smoothness and ease of swallowing. Scanning electron micrographs indicated that the superior textural property of the 1:1PH-gel was caused by a network of myosin filaments. Videofluoroscopic examination of swallowing revealed that the 1:1PH-gel was easy to swallow and left little residue in the oropharynx. These results proved the utility of pressurization in creating a dysphagia meat diet.

Hindlimb unloading decreases thioredoxin-related antioxidant proteins and increases thioredoxin-binding protein-2 in rat skeletal muscle

To investigate role(s) of thioredoxin-related antioxidant proteins in disuse muscle atrophy, we examined the levels of thioredoxin-1 (Trx-1), peroxiredoxin-3/SP-22 (Prx-3) and thioredoxin-binding protein-2 (TBP-2) in rat soleus muscle subjected to hindlimb unloading (HU) for 2, 4, 7 or 14 days. The muscle weight loss was initially observed on day 4. The increases in aclorein- and malondialdehyde-modified proteins, and the decreases in the levels of Trx-1, Prx-3 and Mn-SOD were observed in the late phase of muscle atrophy, whereas, the increase in mRNA expression of TBP-2, a negative regulator of thioredoxin, preceded muscle atrophy. These findings suggest that the decrease of those antioxidant proteins, particularly a marked decrease of Trx-1, may be responsible for the enhanced oxidative damage during the late phase of disuse muscle atrophy. Furthermore, the increase in TBP-2 preceding the muscle atrophy may suppress the thioredoxin-mediated redox signaling, which can be an initial trigger leading to disuse muscle atrophy.

Dynamics of capsule swallowing by healthy young men and capsule transit time from the mouth to the stomach.

We examined the dynamics of capsule swallowing by healthy young men using the anterior-posterior view of videofluoroscopy as a first step in a study on capsule swallowing by dysphagic patients. The subjects were 14 healthy men who did not have any complaint of dysphagia. They were asked to swallow a #4 hard gelatin capsule filled with barium sulfate with 15 ml of water during the videofluoroscopic examination. This examination was repeated three times for each subject (total of 42 trials). In four of the 14 subjects, a swallowed capsule was retained at the upper esophageal sphincter, or the broncho-aortic constriction of the esophagus, or the lower esophageal sphincter. Except where retention occurred, the average capsule transit time from the mouth to the stomach was 6.0 ± 2.4 s. Three of the four subjects who had capsule retention did not realize that the swallowed capsule was retained en route to the stomach. By considering the dynamics of swallowing a capsule with 15 ml of water in healthy men, we should be able to reveal the dynamics of capsule swallowing in dysphagic patients, and the capsule transit time from the mouth to the stomach.

Workplace Disability Management in Postpolio Syndrome

Postpolio syndrome (PPS) is generally defined as a clinical syndrome of new weakness, fatigue, and pain in individuals who have previously recovered from acute paralytic poliomyelitis. These new problems may lead to loss of employment as well as new deficits in instrumental activities in daily living (cleaning, washing, shopping, transportation, etc.), walking, climbing stairs, and personal assistance. We presented three cases of PPS with working disabilities in Japan, and stated the issues confronted with. Particularly at the workplace, PPS individuals need special supports from both rehabilitation medicine and occupational health services, including improved nutrition, achieving ideal body weight, regular and sensible exercise, frequent checkups, and modifying working conditions.

A Case of Apoplexy Attack-Like Neuropathy due to Hereditary Neuropathy with Liability to Pressure Palsies in a Patient Diagnosed with Chronic Cerebral Infarction

Hereditary neuropathy with liability to pressure palsies is an inherited disease associated with the loss of a copy of the PMP22 gene. The condition leads to mononeuropathy due to compression and easy strangulation during daily life activities, resulting in sudden muscle weakness and sensory disturbance, and displaying symptoms similar to cerebrovascular diseases. We report the case of an 80-year-old man with left paralysis due to chronic cerebral infarction. His medical history indicated remarkable recovery from about 4 months after the onset of left hemiplegia with predominant involvement of the fingers. Despite subsequent recurrent monoplegia of the upper or lower limbs, brain magnetic resonance imaging consistently revealed only previous cerebral infarction in the right corona radiata without new lesions. Medical examination showed reduced deep tendon reflexes in his extremities on both the healthy and hemiplegic sides. Nerve conduction studies showed delayed conduction at the bilateral carpal and cubital tunnels and near the right caput fibulae. Genetic analysis revealed loss of a copy of the PMP22 gene. Thus, he was diagnosed with a cerebral infarction complicated by hereditary neuropathy with liability to pressure palsies. Stroke patients develop sudden muscle weakness and sensory disturbance. However, if such patients have no hyperactive deep tendon reflexes and show atypical recovery of paralysis that does not correspond to findings of imaging modalities, nerve conduction studies and genetic analysis may be necessary, considering the complication of hereditary neuropathy with liability to pressure palsies.

1-A-D-13. Repeater F-waves may be derived from the reinnervated type I motor unit in polio survivors

Despite our previous report that repeater F-waves are characteristic findings in polio survivors, the origin of these repeater F-waves remains to be clarified. In this study, 43 polio survivors (polio group) and 20 healthy age- and height-matched volunteers (control group) underwent motor conduction studies of their bilateral median and tibial nerves, including F-waves elicited by 100 stimuli. The polio group showed significantly prolonged F-wave minimal latency in the median nerve compared to the controls. The mean F-wave amplitude was not significantly different between the groups. Concerning the repeater F-waves in the polio group, minimal latencies were significantly prolonged, and their mean amplitudes were significantly higher than for the non-repeater F-waves of both nerves. According to publications on muscle pathology, polio survivors show a characteristic predominance of type I muscle fibers. Therefore, these repeater F-waves, with a prolonged minimal latency and high amplitude, might be derived from the reinnervated type I motor unit. These findings suggest that repeater F-waves could indicate motor unit pathophysiology in polio survivors.