ISSN:0195-9131    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Diabetes mellitus is a common chronic disorder the primary therapeutic principles of which have long been based on the combination of physical activity with appropriate diet. Although exercise in insulin-dependent diabetes mellitus (IDDM) may be associated with metabolic deterioration in the case of lack of adequate provision of insulin and carbohydrate in balanced amounts, the beneficial effects of exercise in diabetes are numerous. Exercise facilitates the utilization of glucose as the main source of energy for contracting muscles and decreases peripheral insulin resistance. Limited epidemiological studies have demonstrated that lack of physical activity may be involved in the epidemic outburst of non-insulin-dependent diabetes mellitus (NIDDM) in some unusual populations. Long-term studies are still needed to show that lifelong physical training and exercise reduce morbidity and mortality in diabetes.

ISSN:0195-9131    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Fuel homeostasis and blood glucose levels are remarkably well maintained during exercise in healthy individuals. However, in insulin-dependent diabetics, the very basis for fuel homeostasis adjustments, i.e., a normal endogenous insulin production, is absent. The metabolic alterations characterizing diabetes may, therefore, under certain circumstances lead to pertubations of fuel homeostasis. Thus, exercise in the hyper-insulinemic patients may result in hypoglycemic reactions and, in hypoinsulinemic patients, in increased blood glucose levels. In addition, diabetes mellitus is associated with peripheral insulin resistance, which may result in a deterioration of the overall glucose homeostasis and consequently make the treatment more difficult to manage. Regular physical activity has been shown to normalize the peripheral insulin resistance in insulin-dependent diabetics. Knowledge about these responses is important in order to enable this patient group to participate in physical activities on the same conditions as non-diabetics. However, advice on how insulin-dependent diabetics should adjust insulin or diet before exercise is difficult to give due to high interindividual variability in response to exercise. Thus, individualized recommendations for exact treatment modification in association with exercise are necessary.

ISSN:0195-9131    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

The evidence that exercise reduces resistance to the action of insulin has generated interest in the possibility that endurance exercise training may be a worthwhile primary therapeutic intervention in the treatment of mild non-insulin-dependent diabetes mellitus (NIDDM) (11). Unfortunately, the results of several studies of exercise training in NIDDM have been discouraging since improvements in oral glucose tolerance (OGT) did not occur or were quite modest even though insulin resistance was reduced. Recently it was determined that 12 months of endurance exercise training at 75–90% of &OV0312;o2maxcould normalize OGT in men with mild NIDDM when the post-training OGTT was performed within 18 h of the last bout of exercise. This, coupled with the fact that the enhanced action of insulin is lost in trained persons within a few days of cessation of training, suggests that improved glucose tolerance in NIDDM patients may be partly due to the persistent effects of the last bouts of exercise. Acute exercise in the form of 7 d of intense walking/cycling has been shown to improve glucose tolerance despite a significantly smaller increase in plasma insulin levels during the OGTT in NIDDM. Apparently, the improvement in OGT was due to a decrease in resistance to insulin over the short term since no changes in body weight, body fat, or &OV0312;o2maxtook place. Thus, acute exercise of sufficient intensity and duration can increase peripheral insulin action and may contribute to the effects of long-term exercise training on improvement in OGT and the amelioration of insulin resistance in patients with NIDDM.

ISSN:0195-9131    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

It has been reported that catecholamine release is associated with stressful events and that adrenaline administration induces hyperfibrinolysis. To examine the possible involvement of the adrenoreceptor mechanism in the regulation of fibrinolytic activity at rest and to maximum exercise, 12 healthy volunteers (six males and six females, age range 19–21 yr) were orally medicated with two formulations of a beta blocker. The drug treatments consisted of 1) a single dose of OM756 alpha 10 mg propranolol “Inderal” tablet, 2) a single dose of a generic 10 mg propranolol tablet, and 3) a single dose of generic placebo. The drug administrations were assigned to the subjects using a complete Latin square design and double-blind procedure and were separated by 7 d. Two hours after the administration of the respective drug treatment, subjects exercised to maximal capacity using a graded exercise protocol on a bicycle ergometer. Prior to and 2 h after the drug administration and immediately after maximum exercise, heart rate, blood pressure, and oxygen consumption were measured and venous blood was removed and analyzed for fibrinolytic activity using a standard fibrin plate method. ANOVA showed that the resting and maximum heart rates were significantly reduced (P< 0.05) following oral premedication with either of the two formulations of beta blocker, while blood pressure and oxygen consumption were unaffected. ANOVA also showed no difference in the resting fibrinolytic activity 2 h post-administration of the drug treatments but a significant decrease (P< 0.05) in the normal fibrinolytic response to maximum exercise. It was concluded, therefore, that the resting level of fibrinolytic activity is not mediated via an adrenergic pathway but that the enhanced fibrinolytic activity to maximum exercise is partially regulated via an adrenoreceptor mechanism.

ISSN:0195-9131    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Changes were explored in the behavior of circulating monocytes and their potential association with the activation of the coagulation system as assessed following strenuous exercise. Twelve men and nine women from the Norwegian national cross country skiing team and 19 men and six women from a level just below that of the national team were studied before and after ski race competition. Mononuclear cells were isolated after incubation of heparinized blood with lipopolysaccharides (LPS; 3 ng·ml−1) for 2 h. After a 50 km race for men, the specific thromboplastin activity of the stimulated monocytes rose from 3.5 x 10−3/106cells to 21.4 x 10−3/106cells. This probably reflects the mobilization of a new population of monocytes that are more sensitive to such stimuli. Resting top-athlete skiers had monocytes which were significantly less responsive to the LPS stimulus compared to nontrained people. There was an inverse correlation of plasma factor VII and the monocyte responsiveness toin vitrostimulation (r = 0.814;P< 0.002) from blood drawn after a race. Furthermore, factor VII was significantly reduced after a 50 km race, and a modest decline in the fibrinogen level was also observed (P< 0.05). It is concluded that endurance ski racing causes white cell mobilization and more active white cells that may induce activation of the coagulation system and account for the involvement of factor VII and fibrinogen.

ISSN:0195-9131    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

In order to compare the clinical presentation of overuse injuries in older and younger athletes, retrospective patient chart data were obtained from cases which had been referred to an outpatient sports medicine clinic over a 5-yr period. A total of 1,407 cases were studied comprising two populations separated by significantly (P< 0.001) different ages: 685 “old” (mean age = 56.9 ± 6.1 yr) and 722 “young” (mean age = 30.4 ± 8.1 yr). Although the two subpopulations demonstrated modest differences in sport activity at the time of injury, specific diagnoses, and anatomic location of injury, many similarities existed between the groups. Running, fitness classes, and field sports were more commonly associated with injury in the younger group, while racquet sports, walking, and low intensity sports were more commonly associated with injury in the older group. The frequency of tendinitis was similar in both age groups, while metatarsalgia, plantar fasciitis, and meniscal injury were more common in the older population, and patellofemoral pain syndrome (PFPS) and stress fracture/periostitis were more common in the younger population. Anatomically, injury sites in the foot were more frequent in the older group, while injury sites in the knee were more frequent in the younger group. In the older population, the prevalence of osteoarthritis was 2.5 times higher than the frequency of osteoarthritis as the source of activity-related pain. In the older group, 85% of the diagnoses were overuse injuries known to respond to conservative treatment, 14.4% of the cases required consultative referral, and only 4.1% required surgery.

ISSN:0195-9131    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

The immune response was assessed in 13 competitive bodybuilders self-administering anabolic-androgenic steroids and ten competitive bodybuilders not administering these drugs. Laboratory assessment included the number and relative distribution of T-cells, T-helper/inducer cells, T-cytotoxic/suppressor cells, activated T-cells, lymphocyte transformation to the mitogens, pokeweed mitogen (PWM), phytohemagglutinin (PHA), Concanavalin-A (CON-A),Staphylococcus aureusCowan strain I (SAC), serum immunoglobulins, and natural killer (NK) activity. There were no significant differences in T-cell subsets among steroid users and non-users, but lymphocyte transformation studies revealed that the anabolic-androgenic steroid-using group had enhanced proliferative ability to the B-cell mitogen, SAC, in comparison to non-bodybuilding controls. NK activity was significantly (P< 0.05) augmented in the anabolic-androgenic steroid users but not in the non-using bodybuilders. Serum immunoglobulin levels, in particular IgA, were significantly (P< 0.017) lower in the steroid-using group. Four of 13 steroid users and three of eight non-steroid-using bodybuilders had detectable antinuclear antibodies. These studies indicate that 1) anabolic-androgenic steroid use as practiced by contemporary athletes is a potent modulator of immune responsiveness and 2) autoantibodies are prevalent in strength-trained men even in the absence of anabolic steroid use.

ISSN:0195-9131    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Calcium plays numerous roles in striated muscle, including excitation-contraction coupling and the stimulation of substrate oxidation by the mitochondria. These two topics are considered in this symposium. The purpose of this introductory paper is to present a conceptual framework about the control of calcium movements in striated muscle. Additionally, we provide a brief historical perspective regarding the key research observations leading to our current understanding of the various cellular systems controlling calcium flux in the muscle cell.

ISSN:0195-9131    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

In both types of striated muscle (skeletal and cardiac), calcium flux across the plasma membrane (sarcolemma) is regulated by at least three distinct membrane proteins; a voltage-dependent Ca2+channel, Ca2+pump (Ca2+ATPase), and the Na+/Ca2+antiporter. Each of these proteins is subject to regulation by intracellular second messengers. The magnitude and the role of this transsarcolemmal calcium flux are quite different between cardiac and skeletal muscle. In cardiac muscle, the influx is large, precedes, and is obligatory for contraction. There is general agreement that this influx is the trigger for Ca2+release from the sarcoplasmic reticulum (SR) in the heart according to the Ca2+-induced Ca2+release hypothesis. Variations in the transsarcolemmal Ca2+influx have a profound effect on the strength of cardiac contraction, and it appears that this is the primary physiological strategy for regulation of contractility. In skeletal muscle, on the other hand, the T-tubules represent the richest source of dihydropyridine (DHP)-sensitive calcium channels known to exist, yet the influx of Ca2+is proportionally much smaller and a significant portion enters the fiber following the twitch. While the majority of the Ca2+influx is twitch dependent, it is quite clear that contraction in skeletal muscle is not predicated on this influx. It has been proposed that these DHP channels act as voltage sensors in order to initiate release of SR Ca2+; however, the link between the sensors and the opening of the SR Ca2+(ryanodine-sensitive) channel is unknown. Transsarcolemmal Ca2+transport appears to be subject to intense regulation to modify the acute response and demonstrates some plasticity in the adaptation to chronic perturbations.

ISSN:0195-9131    

出版商:OVID    

年代:1989

数据来源: OVID