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There are positive health effects of exercise performed at regular intervals also in high volume exercisers. However, at present there is no exact definition of the optimal dose or the maximal safe dose of exercise, nor can the level of exercise to induce increased risk of harmful effects be defined. People who often exercise with a high volume and intensity should therefore individually consider the health-related effects and possible risks of their training as well as the physical or psychological warning signals.

The Danish Fitness and Nutrition Council has examined the scientific literature to evaluate the effects of a physically inactive lifestyle on health in the adult population. Physical inactivity is defined as less than 2.5 hours of moderately intense activity per week. 30-40% of the adult Danish population is defined as physically inactive. A physically inactive lifestyle has a negative impact on metabolic and cardio-vascular functions and increases the risk of developing lifestyle diseases. Furthermore, physical inactivity increases the risk of disability among the elderly.

Recent research indicates that physical activity before and during pregnancy helps lower the risk of gestational diabetes and preeclampsia. Physical activity during pregnancy has no negative effects on the risk of preterm birth, low birth weight and birth complications; however, thus far the topic has not been widely explored. In the light of the available findings, although of limited scope, it seems justified to encourage healthy pregnant women who are already physically active at the onset of pregnancy to maintain their activities but to reduce their intensity and to encourage pregnant women who are not already physically active to initiate physical activity.

Obesity and physical inactivity are both associated with illness and death. A review of the literature has shown that the objectively measured level of fitness and self-reported physical activity both have a prognostic relationship with death from all causes, independently of BMI. Furthermore, there is evidence for a dose-response effect of physical activity. It is concluded that regular physical activity has health-beneficial effects which are beyond its effect on weight control.

Respiratory syncytial virus (RSV) accounts for considerable morbidity among infants and elderly, that are otherwise immunocompetent. Immunocompromised haematological patients--in particular bone marrow transplant (BMT) recipients with leukopenia--are at high risk for severe, usually fatal, RSV-pneumonia. No randomized, placebo-controlled studies of aerosolized ribavirin for BMT patients with RSV-pneumonia have been conducted, or can be anticipated. We summarize existing case reports providing circumstantial evidence in favour of an active diagnostic and early therapeutic approach to these patients.

During the last years studies on human immune responses to specific micro-organisms have contributed to an increased understanding of the structure and function of the immune system. T lymphocytes with a special antigen receptor (gamma/delta cells) are thus probably important in some infectious diseases such as malaria and tuberculosis. The discovery of T-cell responses to protein-free fractions of mycobacteria and Leishmania parasites has lead to the identification of non-protein T-cell antigens. T-cells that express the CD4 receptor on their surface and are capable of lysing infected target cells have been found in viral infections. It has furthermore been found, that the composition of the signal mediators (cytokines) secreted by activated T-cells can determine the outcome of a number of infections. In the future it may be possible to include enhancement of protective immune reactions in the treatment of infectious diseases to a higher extent than now.

Treatment of patients with sepsis with monoclonal antibodies against lipopolysaccharide, tumour necrosis factor or treatment with soluble TNF-receptors or interleukin-1 receptor antagonist have not had any effect on mortality. Treatment with intravenous polyclonal nonspecific immunoglobulin has been shown to have beneficial efficacy on mortality. However, the number of patients included in the latter treatment studies are limited, the patients studied are heterogeneous and do not allow to conclude that sepsis patients should be routinely treated with immunoglobulins.

Up to 70% of individuals with primary HIV infection will develop symptoms of an acute illness. The most common symptoms reported are fever, generalized lymphadenopathy, arthralgia and myalgia, headache, pharyngitis, enanthema, skin rash, diarrhoea, and mucocutaneous ulcerations. More rarely, oesophageal candidiasis, meningoencephalitis, rhabdomyolysis and epiglottitis have been reported. The diagnosis of the acute HIV infection syndrome can be established by demonstrating antibodies to HIV or by demonstration of HIV antigen positivity. Detection of virus through culture or PCR may prove to be more sensitive, but are not yet used as routine methods. The course of the primary infection has prognostic importance for the subsequent course of HIV infection. This probably reflects the importance of both the viral phenotype and of the initial immune response to HIV. Primary HIV infection should be considered in any patient with possible exposure to HIV presenting with fever of unknown cause.

More than 50% of individuals with primary HIV infection have a symptomatic febrile illness associated with seroconversion. The most common clinical picture is a mononucleosis-like or influenza-like illness but almost any organ system may be involved, and primary HIV infection is often an imitator of other acute diseases. Six cases of symptomatic primary infection are described, one with a characteristic presentation, and five cases respectively presenting with colitis, rhabdomyolysis, epiglottitis, cold agglutination haemolysis and meningitis as marked symptoms.

Twenty-one patients fulfilling the Center for Disease Control criteria for chronic fatigue syndrome (CFS) were examined in a controlled study. Viral antibodies and tests evaluating the immune system were investigated in the patients and in a control group of 21 sex- and age-matched individuals. Production in vitro of the predominantly T-cell-derived cytokines interleukin-2 and interferon-gamma was significantly higher in patients with CFS compared the control group. Furthermore, the serum concentrations of IgA and IgE were significantly lower in patients with CFS; however, the values were within the normal reference range. All other variables were similar in the two groups. This study does not suggest a clearly disordered immune system or a chronic viral infection as a major pathogenetic factor in CFS. Longitudinal studies of immunological and virological parameters in CFS are warranted as are studies on patients that are severely handicapped.

The relation between fatty acid composition in plasma and natural killer (NK) cell activity and the relation between fatty acid composition of diet and NK cell activity was evaluated in healthy elderly men. The correlations between basal NK activity and the fraction of plasma fatty acids consisting of total polyunsaturated fatty acids (PUFA), total n-6 fatty acids and linoleic acid were r = -0.68, p = 0.006, r = 0.62, p = 0.014 and r = 0.52, p = 0.048, respectively. Significant negative correlations were also found between alpha-interferon stimulated NK cell activity and the three groups of fatty acids and between interleukin-2 stimulated NK cell activity and PUFA. Likewise, negative correlations between grammes of PUFA in diet, determined from two four-day registration-periods, and basal NK and alpha-interferon stimulated NK cell activity were found. No significant negative correlation between percentage intake of n-3 fatty acids and NK cell activity was found. It is concluded that the type of dietary fatty acids influence NK cell activity in elderly men. A high intake of n-6 polyunsaturated fatty acids may be detrimental to cellular immune defence mechanisms in the elderly.

The study comprises a follow-up (11-13 years) of an orthopaedic department's first 131 consecutive cemented total hip arthroplasties (THA). All operations were performed with Richards' Series 2. Posterior approach, plug, lavage, cementation with cement pistol, antibiotics and low-dose heparin. At the time of follow-up 44 patients (38%) were dead (= 49 THA), and 56 patients representing 65 THA (50%) were available for the follow-up, on average 11.95 years (11-13 years) after the operation. The patients hip/hips were examined as regards a) pain b) walking ability and c) hip-mobility (M. d'Aubigné) (HFI). A frontal x-ray of the pelvis and hip/hips was taken. The examining surgeon evaluated the hip/hips based on a clinical examination and the x-ray as 1 = stable, 2 = perhaps loose, 3 = most likely loose and 4 = definitely loose both with regard to the acetabular and femoral component. Pre-operatively 78% of the patients had an ideopathic coxarthrosis. Eight patients had considerable postoperative complications. Ten patients (7.8%) were reoperated during the examination period: two due to loosening of the total prosthesis, one due to loosening of the cup, three due to loosenings of the femoral component, two because of recurring luxations, one late (deep) infection and one fracture of the femur near the prosthesis. Preoperatively the patients' HFI was at 8.6, at follow-up 15.8. The clinical and the radiographic examination showed that 86% of the acetabular cups and 63% of the femoral components were fixed solidly.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects on the immune system of sudden physical exercise and degree of training are reviewed. During moderate as well as strenuous physical exercise natural killer (NK) cells especially, but also T and B cells are released into the blood. A few hours after moderate physical exercise the immune system is back to the pre-exercise state, but following strenuous exercise the lymphocyte concentration and the NK and B cell functions are suppressed. The immune suppression following strenuous exercise is at least partly due to release of prostaglandins from an elevated number of monocytes in the circulation. The importance of stress hormones for mediating the immune modulation is discussed. Examination of trained persons at rest show that these have elevated NK cell activity when compared to matched controls. There are sporadic reports in the literature, showing that persons who train moderately have fewer infections, while persons who train very hard have increased risk of upper respiratory diseases. These findings are in accordance with the observed immune modulation on moderate versus strenuous exercise. The effects of physical training in relation to acute and chronic diseases are evaluated.