Effects of Rest Interval on Strength Recovery in Breast Cancer Survivors.

The purpose of this study was to compare the acute effect of 2 different resting intervals (RI) between sets of isokinetic knee extension exercise on peak torque (PT) and total work (TW) in breast cancer survivors (BCS) and control group (CNT). 16 BCS (52±4 years) and 14 CNT (53±6 years) performed 3 sets of 10 unilateral isokinetic knee extension repetitions at 60°.s(- 1) on 2 separate days with 2 different RI between sets (1 and 2 min). There was a significant interaction between groups vs. exercise sets (p=0.03) and RI vs. exercise sets (p<0.001) for PT. PT was greater in CNT at 1(st) and 2(nd) sets compared to BCS group (CNT, 133.4±20.8 and BCS 107.6±19.9 Nm, p=0.012 and CNT, 118.9±19.6 and BCS, 97.1±15.9 Nm, p=0.045, respectively). The TW of the knee extensor was significant greater in CNT than BCS group for all 3 knee extension exercise sets. In conclusion, the present study suggests that Breast Cancer Survivors women may need a longer rest interval (longer than 2 min) to be able to fully recover during a 3 sets of isokinetic knee extension exercise training session.

Muscle tissue adaptations to hypoxia.

This review reports on the effects of hypoxia on human skeletal muscle tissue. It was hypothesized in early reports that chronic hypoxia, as the main physiological stress during exposure to altitude, per se might positively affect muscle oxidative capacity and capillarity. However, it is now established that sustained exposure to severe hypoxia has detrimental effects on muscle structure. Short-term effects on skeletal muscle structure can readily be observed after 2 months of acute exposure of lowlanders to severe hypoxia, e.g. during typical mountaineering expeditions to the Himalayas. The full range of phenotypic malleability of muscle tissue is demonstrated in people living permanently at high altitude (e.g. at La Paz, 3600-4000 m). In addition, there is some evidence for genetic adaptations to hypoxia in high-altitude populations such as Tibetans and Quechuas, who have been exposed to altitudes in excess of 3500 m for thousands of generations. The hallmark of muscle adaptation to hypoxia in all these cases is a decrease in muscle oxidative capacity concomitant with a decrease in aerobic work capacity. It is thought that local tissue hypoxia is an important adaptive stress for muscle tissue in exercise training, so these results seem contra-intuitive. Studies have therefore been conducted in which subjects were exposed to hypoxia only during exercise sessions. In this situation, the potentially negative effects of permanent hypoxic exposure and other confounding variables related to exposure to high altitude could be avoided. Training in hypoxia results, at the molecular level, in an upregulation of the regulatory subunit of hypoxia-inducible factor-1 (HIF-1). Possibly as a consequence of this upregulation of HIF-1, the levels mRNAs for myoglobin, for vascular endothelial growth factor and for glycolytic enzymes, such as phosphofructokinase, together with mitochondrial and capillary densities, increased in a hypoxia-dependent manner. Functional analyses revealed positive effects on V(O(2)max) (when measured at altitude) on maximal power output and on lean body mass. In addition to the positive effects of hypoxia training on athletic performance, there is some recent indication that hypoxia training has a positive effect on the risk factors for cardiovascular disease.

[Acquired immunodeficiency syndrome (AIDS). An update after 4 years]. / Das erworbene Immunmangelsyndrom (AIDS). Eine Bilanz nach 4 Jahren.

At the end of December 1984, 8246 AIDS cases had been reported in the United States, and 762 cases in Europe. The main risk groups are homosexual and bisexual men (73%), heterosexual i.v. drug addicts (17%) and Haitians (4%). AIDS is diagnosed in patients meeting the clinical criteria of the CDC surveillance definition (opportunistic infections and/or Kaposi's sarcoma). The prevalence of HTLV-III antibodies in risk groups is high, its prognostic significance still controversial. Laboratory methods to determine the more relevant circulating viral proteins or the whole virus are now being developed. Limited studies to evaluate the possibility of reconstituting the immune system of AIDS patients with interleukin-2 and gamma-interferon have proved unsuccessful. successful. Several new drugs with possible antiviral properties are now being evaluated in first clinical trials.