ABSTRACT
The objective of this study was to investigate whether isometric resistance exercise (IRE) can attenuate musculoskeletal atrophy during unloading and accelerate its recovery during reloading. Twenty-six female Fischer 344 rats, aged 16 weeks, had their hindlimbs suspended for 3 weeks (unloading) ; 12 of these rats were allowed subsequent cage activity (reloading) for 3 weeks with or without IRE. IRE (stationary support on a cylindrical grid inclined 60 or 80 degrees) was done for 30 min/day, 6 days/week, with an additional load of 30% or 50% body mass attached to the tail during the unloading and reloading periods. The tibial bone and hindlimb skeletal muscles from four experimental and two age-matched control groups were evaluated with dual-energy X-ray absorptiometry, mechanical testing, and muscle mass measurement. Bone mineral density (BMD) was measured in the whole tibia and in 7 regions divided equally along the long axis of the epiphysis from proximal (R1) to distal (R7) . After unloading, fat-free dry mass (FFDM), bone mineral content (BMC), and BMD of the whole tibia decreased by 8%, 10%, and 6%, respectively. FFDM and BMC, but not BMD, returned to the levels of age-matched controls during reloading. Unloading-induced decreases in BMD were observed in the regions from the proximal epiphysis to the diaphysis (R1 to R4) and the distal epiphysis (R7) . The rate of decrease in BMD was regionally specific and was particularly pronounced (12%) in the most proximal region (R1) . These findings indicate regional variations in responses of BMD to skeletal unloading. The BMD in R2 to R4 remained less than that in age-matched control after reloading. No significant changes were observed in maximum breaking load, energy, and deformation after unloading and reloading. Hindlimb-unloading induced loss of mass in the soleus (38%), plantaris (14%), gastrocnemius (25%), tibialis anterior (8%), extensor digitorum longus ( 8%), and rectos lemons (17%) muscles, but the mass of muscles, except for the soleus muscle, recovered during reloading. IRE ameliorated the loss of mass in the soleus and gastrocnemius muscles during unloading but did not promote the recovery of mass in any muscles during reloading. Moreover, IRE showed no effect on bone responses after unloading and reloading. This lack of beneficial effects of IRE on osteopenia may be due, in part, to insufficient exerciseinduced load. We concluded that 1) regional analysis of BMD can be used to assess local bone metabolism, 2) the response of BMD to altered loading conditions does not necessarily depend on the response of muscle mass, 3) recovery from osteopenia progresses more slowly than that from sarcopenia, and a longer time than the unloading period is required to restore BMD. Further studies are needed to develop more effective countermeasures against osteopenia and sarcopenia.
ABSTRACT
A 61-year-old woman with paresthesia and coldness of the right forearm came to our institute. Her right arm was strangulated and tracted by a vinyl string tied at her right brachium. No pulsation of her right radial artery was detected, and her forearm had swollen with subcutaneous hematoma. Her arteriography showed occlusion of the distal site of the right brachial artery, and just proximal to the brachial arterial bifurcation was enhanced by collaterals. She underwent emergency revascularization 6h after injury. There was a thrombus in the artery at the strangulated site, and the arterial intima was circumferentially dissected. The injured site of the artery was completely resected and interposed with basilic vein. Although 8h had passed from injury to reperfusion, myonephropathic metabolic syndrome did not occur after the operation. Her brachial arterial pulsation is now well palpable. The arterial occlusion was probably caused by the circumferential tear of the intima due to not only direct strangulation but also strong traction of the arm. It is necessary to resect a sufficient length of injured artery.
ABSTRACT
The effects of exercise and dietary therapy on the prevention of diabetic nephropathy (DN) were compared. Thirty-two male OLETF rats were divided into four groups (Ex, Diet, Sed, Pre) . Fourteen LETO rats served as the normal controls. Therapy was conducted for 10 weeks from age 22 to 31 weeks. The Ex group was trained by voluntary exercise, and the Diet group had a restricted food intake resulting in the same BW as that of the Ex group. The Ex developed a significant increase in urinary albumin excretion compared to the Diet group, although significantly less than the Sed group. Blood pressure in the Ex group showed a tendency to be higher during therapy. BW and serum lipids were significantly reduced, and glucose intolerance was improved in both the Ex and Diet groups. There were no differences in the metabolic indices between the Ex and Diet groups. The Ex group showed a significantly heavier kidney weight and a tendency for enlargement of the glomerular area and volume. The protective effect of DN through improvement of the metabolic dis-order by exercise might be offset by exercise-induced renal loads. Control of exercise intensity and blood pressure appear to be important as well as the improvement of glucose intolerance and lipid metabolisms in exercise therapy to prevent an occurrence and development of DN.
ABSTRACT
The effect of ingestion of a chilled carbohydrate and electrolyte solution on metabolic and hormonal responses and water-electrolyte balance was studied after two 5-km runs in hot outdoor conditions (Temp, 30.6-30.9°C ; humidity, 61.3-62.4%) . Eight healthy females (mean age 21.8 years) participated in : 1) a control experiment (Copt) with no fluid intake, 2) an experiment with 500 ml of tap water (WI), and 3) an experiment with 500 ml of sports beverage (SB) containing carbohydrate and electrolytes each of which were given after the 1st 5-km run, followed by a second 5-km run with an equivalent to 68.7-72.3% of VO<SUB>2</SUB>max. In the Cont, decreases in %ΔPV and blood glucose (BS) and increases in serum osmolality (Sosm), free fatty acid (sFFA) and plasma hormone concentrations related to regulation of the water-electrolyte balance in the body persisted after the 2 nd run. The intake of the sports beverage prevented hypoglycemia and ketoacidosis, as shown by an increase in sFFA and positive results for qualitative analysis of ketone body in the urine, and quick recovery of plasma volume following an endurance run under a hot environment. This study suggests that fluid replacement with a sports beverage containing carbohydrate and electrolytes was superior to plain water or no fluid ingestion in terms of metabolic and hormonal responses and the recovery of plasma volume and elevated rectal temperature following an endurance run under hot conditions.