Chronic intermittent hypoxia and incremental cycling exercise independently depress muscle in vitro maximal Na+-K+-ATPase activity in well-trained athletes

Athletes commonly attempt to enhance performance by training in normoxia but sleeping in hypoxia [live high and train low (LHTL)]. However, chronic hypoxia reduces muscle Na⁺-K⁺-ATPase content, whereas fatiguing contractions reduce Na⁺-K⁺-ATPase activity, which each may impair performance. We examined whether LHTL and intense exercise would decrease muscle Na⁺-K⁺-ATPase activity and whether these effects would be additive and sufficient to impair performance or plasma K⁺ regulation. Thirteen subjects were randomly assigned to two fitness-matched groups, LHTL (n = 6) or control (Con, n = 7). LHTL slept at simulated moderate altitude (3,000 m, inspired O₂ fraction = 15.48%) for 23 nights and lived and trained by day under normoxic conditions in Canberra (altitude ~600 m). Con lived, trained, and slept in normoxia. A standardized incremental exercise test was conducted before and after LHTL. A vastus lateralis muscle biopsy was taken at rest and after exercise, before and after LHTL or Con, and analyzed for maximal Na⁺-K⁺-ATPase activity [K⁺-stimulated 3-O-methylfluorescein phosphatase (3-O-MFPase)] and Na⁺-K⁺-ATPase content ([³H]ouabain binding sites). 3-O-MFPase activity was decreased by –2.9 ± 2.6% in LHTL (P < 0.05) and was depressed immediately after exercise (P < 0.05) similarly in Con and LHTL (–13.0 ± 3.2 and –11.8 ± 1.5%, respectively). Plasma K⁺ concentration during exercise was unchanged by LHTL; [3H]ouabain binding was unchanged with LHTL or exercise. Peak oxygen consumption was reduced in LHTL (P < 0.05) but not in Con, whereas exercise work was unchanged in either group. Thus LHTL had a minor effect on, and incremental exercise reduced, Na⁺-K⁺-ATPase activity. However, the small LHTL-induced depression of 3-O-MFPase activity was insufficient to adversely affect either K⁺ regulation or total work performed.

Comparison of tissue dosimetry in the mouse following chronic exposure to arsenic compounds

Several chronic bioassays have been conducted in multiple strains of mice in which various concentrations of arsenate or arsenite were administered in the drinking water without a tumorigenic effect. However, one study (Ng et al., 1999) reported a significant increase in tumor incidence in C57Bl/6J mice exposed to arsenic in their drinking water throughout their lifetime, with no tumors reported in controls. A physiologically based pharmacokinetic model for arsenic in the mouse has previously been developed (Gentry et al., 2004) to investigate potential differences in tissue dosimetry of arsenic species across various strains of mice. Initial results indicated no significant differences in blood, liver, or urine dosimetry in B6C3F1 and C57Bl/6 mice for acute or subchronic exposure. The current work was conducted to compare model-predicted estimates of tissue dosimetry to additional kinetic information from the (C57Bl/6 x CBA)F1 and TgAc mouse. The results from the current modeling indicate that the pharmacokinetic parameters derived based on information in the B6C3F1 mouse adequately describe the measured concentrations in the blood/plasma, liver, and urine of both the (C57Bl/6 x CBA)F1 and TgAc mouse, providing further support that the differences in response observed in the chronic bioassays are not related to strain-specific differences in pharmacokinetics. One significant finding was that no increases in skin or lung concentrations of arsenic species in the (C57Bl/6 x CBA)F1 strain were observed following administration of low concentrations (0.2 or 2 mg/L) of arsenate in the drinking water, even though differences in response in the skin were reported. These data suggest that pharmacodynamic changes may be observed following exposure to arsenic compounds without an observable change in tissue dosimetry. These results provided further indirect support for the existence of inducible arsenic efflux in these tissues.

Towards ending the silence: working women caring for children with chronic illness

This paper presents stories from women who work and care for a child with a significant chronic illness or disability. The purpose of this paper is to move towards ending the silence on their lives. A three-phase emergent research design responds to the question: What is life like for a full-time worker who is concurrently the primary carer of a chronically ill child? This paper considers the theory of Silencing the Self (Jack, 1991) in relation to the emergent themes of “Otherness” and “Doing it All.” As in Jack’s study, these women also engaged in silencing of the self. However, unlike the respondents in Jack’s study, these women did not demonstrate feelings of worthlessness and hopelessness for the future, nor were they alone in contributing to their silence. Indeed, many experienced silencing behaviors from others around them, and many rallied against the silence, not accepting that their burden should continue. Consideration of Jack’s theory is made to point out the distinctions between the women in this study and Jack’s study, and analytical commentary is provided to demonstrate the relevance of this analysis in light of the current debates surrounding the Work–Home Conflict and the rising levels of informal care provided by women in our communities.

Effects of chronic treatment with arabose on glucose and lipid metabolism in obese diabetic wistar rats

Aims: The effect of chronic treatment with acarbose on fasting plasma glucose, insulin, triglyceride, cholesterol and free fatty acid (FFA) concentrations, as well as on the glucose and insulin excursions during oral glucose tolerance test (OGTT), in obese diabetic Wistar (WDF) rats was investigated. Methods: Forty-five mature male WDF rats were randomly distributed to one of the three treatment groups (no acarbose, 20 mg and 40 mg of acarbose/100 g of chow, respectively). After 3.5, 7.5 and 11.5 months, animals were tested for glucose tolerance by means of an OGTT, and their respective metabolic profiles were determined. Control determinations were done in obese and age-matched lean animals before the start of the trial. Results: The WDF rats exhibit higher body weight and fasting blood glucose, insulin, triglyceride and cholesterol concentrations compared to lean animals. Moreover, they show marked glucose intolerance as indicated by the glucose and insulin excursions during OGTT. Interestingly, in both treated and untreated animals, a reversion of the hyperglycaemic state as well as an improvement of the glucose tolerance is observed. However, whereas in the group receiving no acarbose this is accounted for by dramatic increases in fasting plasma insulin concentrations and insulin secretion during OGTT (as indicated by the ΔInsulin area), in rats treated with acarbose the reversion of the diabetic state takes place without increments in hormone concentration. In addition, rats treated with acarbose for 3.5 and 7.5 months show lower plasma triglyceride and FFA concentrations, and the same was observed for cholesterol at the highest dosage of the drug. Conclusions: Chronic treatment with acarbose of WDF rats improves the glycaemic and lipidic control as well as the glucose tolerance, with a lower demand of pancreatic insulin than in untreated rats. This data suggests that the long-term modulation of glucose and insulin excursions after meals improves the insulin sensitivity in this rat strain.

The role of peer support in facilitating psychosocial adjustment to chronic illness in adolescence

This article describes a Chronic Illness Peer Support (ChIPS) programme designed to assist young people in their adjustment to life with a chronic medical condition. The ChIPS programme takes a non-categorical approach to participation, recognizing that young people with different medical conditions experience many similar concerns. Support groups are facilitated by a health professional and peer co-leader. Groups meet weekly for 8 weeks and typically include between six and eight young people. Young people can choose to remain involved in broader social, educational and recreational activities following completion of the 8-week programme. We discuss nine psychosocial mechanisms by which peer support groups such as ChIPS might act to improve resilience and well-being among participants. We also discuss some theoretical risks in running support groups for chronically ill young people, which emphasize the importance of training and support of group leaders, including the peer co-leaders. The article concludes with a personal testimony by a ChIPS participant that was prepared for the 2003 Australian and New Zealand Adolescent Health Conference.

Designing the future in wound care: the role of the nurse practitioner

The nurse practitioner is emerging as a new level and type of health care. Increasing specialisation and advanced educational opportunities in nursing and the inequality in access to health care for sectors of the community have established the conditions under which the nurse practitioner movement has strengthened both nationally and internationally. The boundaries of responsibility for nurses are changing, not only because of increased demands but also because nurses have demonstrated their competence in varied extended and expanded practice roles. The nurse practitioner role reflects the continuing development of the nursing profession and substantially extends the career path for clinical nurses.

This paper describes an aspect of a large-scale investigation into the feasibility of the role of the nurse practitioner in the Australian Capital Territory (ACT) health care system. The paper reports on the trial of practice for a wound care nurse practitioner model in a tertiary institution. In the trial the wound care nurse practitioner worked in an extended practice role for 10 months. The nurse practitioner practice was supported, monitored and mentored by a clinical support team. Data were collected relating to a range of outcomes including definition of the scope of practice for the model, description of patient demographics and outcomes and the efficacy of the nurse practitioner service.

The findings informed the development of clinical protocols that define the scope of practice and the parameters of the wound care nurse practitioner model and provided information on the efficacy of this model of health care for the tertiary care environment. The findings further suggest that this model brings expert wound care and case management to an at-risk patient population. Recommendations are made relating to ongoing research into the role of the wound care nurse practitioner model in the ACT health care system.

A pilot study of the eccentric decline squat in the management of painful chronic patellar tendinopathy

Objectives: This non-randomised pilot study investigated the effect of eccentric quadriceps training on 17 patients (22 tendons) with painful chronic patellar tendinopathy.

Methods: Two different eccentric exercise regimens were used by subjects with a long duration of pain with activity (more than six months). (a) Nine consecutive patients (10 tendons; eight men, one woman; mean age 22 years) performed eccentric exercise with the ankle joint in a standard (foot flat) position. (b) Eight patients (12 tendons; five men, three women; mean age 28 years) performed eccentric training standing on a 25° decline board, designed to increase load on the knee extensor mechanism. The eccentric training was performed twice daily, with three sets of 15 repetitions, for 12 weeks. Primary outcome measures were (a) 100 mm visual analogue scale (VAS), where the subject recorded the amount of pain during activity, and (b) return to previous activity. Follow up was at 12 weeks, with a further limited follow up at 15 months.

Results: Good clinical results were obtained in the group who trained on the decline board, with six patients (nine tendons) returning to sport and showing a significantly reduced amount of pain over the 12 week period. Mean VAS scores fell from 74.2 to 28.5 (p = 0.004). At 15 months, four patients (five tendons) reported satisfactory results (mean VAS 26.2). In the standard squat group the results were poor, with only one athlete returning to previous activity. Mean VAS scores in this group were 79.0 at baseline and 72.3 at 12 weeks (p = 0.144).

Conclusion: In a small group of patients with patellar tendinopathy, eccentric squats on a decline board produced encouraging results in terms of pain reduction and return to function in the short term. Eccentric exercise using standard single leg squats in a similar sized group appeared to be a less effective form of rehabilitation in reducing pain and returning subjects to previous levels of activity.

The effect of topical wheatgrass cream on chronic plantar fasciitis: a randomized, double-blind, placebo-controlled trial

Objectives: To investigate the efficacy of a topical wheatgrass cream for improving pain and function in patients with chronic plantar fasciitis.

Design: Randomized, double-blind, placebo-controlled trial.

Setting: Eighty participants with chronic plantar fasciitis were randomly assigned to a treatment group (wheatgrass cream) or a control group (placebo cream). All participants applied a cream twice daily for 6 weeks. Follow up was conducted at 6 and 12 weeks.

Main outcome measures: Visual Analogue Scale (VAS) for daily first-step pain and the Foot Health Status Questionnaire (FHSQ) for overall foot function. Secondary measures of foot posture, calf muscle strength and range of ankle dorsiflexion were also assessed.

Results: No significant differences were found between groups with respect to main outcomes of first-step pain or foot function at any time. Both groups improved significantly from baseline to 6 weeks, and these improvements were maintained at 12 weeks.

Conclusions: The topical application of wheatgrass cream is no more effective than a placebo cream for the treatment of chronic plantar fasciitis.

Modulation of tumor necrosis factor receptors 1 and 2 in chronic hepatitis B and C: The differences and implications in pathogenesis

Tumor necrosis factor (TNF) plays a role in the pathogenesis of chronic hepatitis B (CHB) and chronic hepatitis C (CHC). The difference in the cytokine responses between hepatitis B virus (HBV) and hepatitis C virus (HCV) infections may have implications in the pathogenesis of these diseases. We performed a comparative study to examine the possible differences in the TNF-TNF receptor (TNFR) response between CHB and CHC. We studied the cytokine levels of 38 patients with CHB, 40 patients with CHC and 9 patients with dual hepatitis B and C, and compared them with the baseline levels of 12 healthy controls. The plasma levels of TNF-, interferon-, interleukin (IL)-2, IL-4, IL-10 and soluble TNFR-1 and 2 (sTNFR-1 and 2) were quantified by enzyme-linked immunosorbent assays. The expression of TNFR-1 and 2 in liver tissues was examined in 30 cases of CHB and 15 cases of CHC by semiquantitative reverse transcription polymerase chain reaction. The results showed that sTNFR-1 levels correlated with liver inflammation in all patients, whereas this correlation was not found with sTNFR-2 or other cytokines. Liver inflammation indicators were higher in HCV RNA+ than in HCV RNA– CHC. Most significantly, sTNFR-1 levels correlated with liver inflammation in CHB, but not in CHC. However, the expression of TNFR-1 and 2 in liver was similar between CHB and CHC. These findings suggest that the TNFR signal transduction pathway is modulated differently in HBV and HCV infection.

Preliminary study of the effect of low-intensity home-based physical therapy in chronic stroke patients

This study was a preliminary examination of the effect of low-intensity home-based physical therapy on the performance of activities of daily living (ADL) and motor function in patients more than 1 year after stroke. Twenty patients were recruited from a community stroke register in Nan-Tou County, Taiwan, to a randomized, crossover trial comparing intervention by a physical therapist immediately after entry into the trial (Group I) or after a delay of 10 weeks (Group II). The intervention consisted of home-based physical therapy once a week for 10 weeks. The Barthel Index (BI) and Stroke Rehabilitation Assessment of Movement (STREAM) were used as standard measures for ADL and motor function. At the first follow-up assessment at 11 weeks, Group I showed greater improvement in lower limb motor function than Group II. At the second follow-up assessment at 22 weeks, Group II showed improvement while Group I had declined. At 22 weeks, the motor function of upper limbs, mobility, and ADL performance in Group II had improved slightly more than in Group I, but the between-group differences were not significant. It appears that low-intensity home-based physical therapy can improve lower limb motor function in chronic stroke survivors. Further studies will be needed to confirm these findings.

Factors associated with chronic plantar heel pain: a systematic review

Chronic plantar heel pain (CPHP) is one of the most common soft tissue disorders of the foot, yet its aetiology is poorly understood. The purpose of this systematic review was to examine the association between CPHP and the various aetiological factors reported in the literature. Seven electronic databases and the reference lists of key articles were searched in August 2005. The resulting list of articles was assessed by two independent reviewers according to pre-determined selection criteria and a final list of articles for review was created. The methodological quality of the included articles was assessed and the evidence presented in each of the articles was descriptively analysed. From the 16 included articles, body mass index in a non-athletic population and the presence of calcaneal spur were the two factors found to have an association with CPHP. Increased weight in a non athletic population, increased age, decreased ankle dorsiflexion, decreased first metatarsophalangeal joint extension and prolonged standing all demonstrated some evidence of an association with CPHP. Evidence for static foot posture and dynamic foot motion was inconclusive and height, weight and BMI in an athletic population were not associated with CPHP. The findings of this review should be used to guide the focus of prospective cohort studies, the results of which would ultimately provide a list of risk factors for CPHP. Such a list is essential in the development of new and improved preventative and treatment strategies for CPHP.

Pathology of chronic achilles-tendon injuries in athletes

Overuse tendon conditions have traditionally been considered to result from an inflammatory process and were treated as such. Microscopic examination of abnormal Achilles-tendon tissues, however, reveals a non-inflammatory degenerative process. The histopathology found in surgical specimens in patients with chronic overuse Achilles tendinopathy and those with Achilles-tendon rupture are reviewed. Seminal studies suggest that so-called tendinitis is a rare condition that might occur occasionally in the Achilles tendon in association with a primary tendinosis. These data have clinical implications and require a review of the traditional classification of pathologies seen in tendon conditions, The authors recommend that nomenclature be based on histopathological findings rather than traditional hypothesis.

Working parents of children with chronic illness/disability: narratives of concern

This paper reports some initial findings of an exploratory, qualitative study of the life and work of people who are, concurrently, parents of a child with chronic illness/disability and working full time. The respondents of this study happen to be all women. Two emerging themes of interest are explored here. The first is a revisit of traditional notions of the abusive workplace, which seems to be of special interest when considering the plight of these women. Secondly, the numerous work and home demands on the working mother, especially the working mother of a child with chronic illness or disability. [twas unsurprising that these women reported extensive and multiple physical and emotional demands while trying to manage full time work with significant home and caring responsibilities. What is surprising is that these narratives of concern have not previously been explored, and should be.

Diet, nutrition and the prevention of chronic diseases : report of a Joint WHO/FAO Expert Consultation

This report examines the science base of the relationship between diet and physical activity patterns and the major nutrition-related chronic diseases. Recommendations are made to help prevent death and disability from major nutrition-related chronic diseases.