Electroencephalogram activity,catecholamines, and lymphocyte subpopulations after resistance exercise and during regeneration

We examined the effect in ten male sports students of 30-min resistance exercise followed by either 45-min regeneration with massage treatment on a massage bench or supine rest serving as control, on plasma catecholamine concentration, number and distribution of circulating white blood cells and central activitity. Resistance exercise increased free plasma adrenaline (A) and noradrenaline (NA), whereas sulpho-conjugated catecholamine concentration remained unchanged as determined by high performance liquid chromatography. Exercise induced leucocytosis and lymphocytosis measured by flow cytometry was predominantly manifested by an increase in the number of lymphocytes, monocytes, CD3⁺ cells, CD8⁺ cells and CD3^– CD16/56⁺ cells. Computer-aided electroencephalography (EEG) revealed significant increases in absolute EEG band power. The increase was highest in alpha 2 with 51.6 (SD 40.2) % (P<0.01), followed by beta 1 with 33.3 (SD 21.0) % (P<0.01), alpha 1 with 31.9 (SD 25.2) % (P<0.01), beta 2 with 30.8 (SD 26.7) % (P<0.01), delta with 26.1 (SD 28.7) % (P<0.05), and theta with 19.8 (SD 16.5) % (P<0.01). All hormone and immunological variables returned to pre-exercise values 45 min after exercise with no differences between massage and control treatments. However, during regeneration differences in absolute EEG-band power were observed between massage and control treatments. In central (C_z, C₃, C₄) and fronto-lateral (F₃, F₄) electrode positions absolute beta 1 spectral power density was significantly lower during massage treatment than during control (Wilcoxon test:P<0.01). Overall, these data demonstrated that an influence of massage treatment on deactivation characteristics could be observed in EEG measurements but not in plasma catecholamine concentration or blood lymphocytes, indicating that computer-aided topographical EEG may be a useful technique for studying activation and regeneration characteristics.     

Mobilization of circulating leucocyte and lymphocyte subpopulations during and after short,anaerobic exercise

Summary A group of 11 healthy athletes [age, 27.4 (SD 6.7) years; body mass, 75.3 (SD 9.2) kg; height, 182 (SD 8) cm; maximal oxygen uptake, 58.0 (SD 9.9) ml · kg^–1 · min^–1] conducted maximal exercise of 60-s duration on a cycle ergometer [mean exercise intensity, 520 (SD 72) W; maximal lactate concentration, 12.26 (SD 1.35) mmol · l^–1]. Adrenaline and noradrenaline, and leucocyte subpopulations were measured flow cytometrically at rest, after 5-min warming up at 50% of each individual's anaerobic threshold (followed by 5-min rest), immediately after (0 min), 15 min, 30 min, and 1, 2, 4 and 24 h after exercise. Granulocytes showed two increases, the first at 15 min and, after return to pre-exercise values, the second more than 2 h after exercise. Eosinophils also increased at 15 min but decreased below pre-exercise values 2 h after exercise. Total lymphocytes and monocytes had their maximal increases at 0 min. Out of all lymphocyte subpopulations CD3^–CD16/CD56⁺- and CD8S⁺ CD45RO^–-cells increased most and had their maximal cell counts at 0 min. The CD3⁺-, CD4⁺CD45RO⁺-, CD8⁺ CD45RO⁺-, and CD19⁺- increased at 0 min, but had their maximum at 15 min. During the hours after exercise CD3^– CD16/CD56⁺-, CD3⁺CD16/CD56⁺-, CD8⁺CD45RO⁺- and CD8⁺ CD45RO^–-cells were responsible for the lymphocytopenia. The CD3⁺- and CD3^– CD16/CD56⁺-cells were lower 24h after exercise than before exercise. Adrenaline and noradrenaline increased during exercise. In conclusion, short anaerobic exercise led to a sequential mobilization of leucocyte subpopulations. The rapid increase of natural killer cells and monocytes may have been due to increased blood flow and catecholamine concentrations. We interpreted from these results that those cells forming the first line of defence can be mobilized faster and disappear out of circulation more rapidly than all other cell populations.     

Exercise-induced changes in the expression of surface adhesion molecules on circulating granulocytes and lymphocytes subpopulations

This study examined the relationship between exercise-induced changes in the concentration of circulating immunocompetent cells and their surface expression of adhesion molecules: L-selectin (CD62L) and three ₂-integrins [LFA-1(CD11a/CD18), Mac-1 (CD11b/CD18), and p150/95(CD11c/CD18)]. Eight young male volunteers exercised on a cycle ergometer for 60 min at 60% maximal oxygen uptake. Peripheral blood samples, collected every 30 min throughout exercise and during the 2-h recovery period, were used for flow-cytometric analysis. The experimental results were compared with control data obtained ever 60 min at corresponding times of the nonexercise day. The exercise regimen induced a granulocytosis and a lymphocytosis, mainly due to an elevation of CD8⁺ and CD16⁺ cells. During recovery, a further granulocytosis occurred but accompanied by a lymphopenia. The increased CD8⁺ cell-count during exercise was characterized by a selective mobilization of the CD62L^– and CD11a^high cells, i.e.primed CD8⁺ cells. A postexercise suppression of CD4⁺ cell-count was derived only from CD62L⁺ cells. The CD11b⁺ and CD11c⁺ lymphocytes also increased during exercise, largely attributable to an increase in CD16⁺ cells which co-expressed CD11b and CD11c molecules. The CD62L surface density of granulocytes increased significantly during recovery. This resulted from a selective influx of CD62L^high granulocytes into the circulation. There were no significant changes in per-cell density of the three ₂-integrins on granulocytes and lymphocytes throughout the experimental period. These results suggest that the cell-surface expression of CD62L (and CD I la) molecules is associated with the differential mobilization of CD8⁺ cells during exercise, the postexercise suppression of CD4^– cell-counts and the granulocytosis following exercise.     

Circulating leucocyte and lymphocyte subpopulations before and after intensive endurance exercise to exhaustion

Summary Seventeen healthy cyclists [age 20.8 (SD 4.8) years; body mass 68.3 (SD 7.7) kg; body fat, 11.4 (SD 2.6) %; height, 179.1 (SD 5.9) cm; 60.9 (SD 7.4) ml · kg^–1 · min^–1] conducted intensive endurance exercise to exhaustion (stress test, ST) on a cycle ergometer at 110% of their individual anaerobic threshold [Th_an,individua; exercise intensity, 3.97 (SD 0.6) W · kg^–1 ; duration, 23.9 (SD 8.3) min; maximal lactate concentration, 7.39 (SD 2.59) mmol · 1^–1]. The distribution of leucocyte subpopulations was measured flow cytometrically: before, immediately after (0), 5 (+5), 30 (+30) and 60 (+60) min after ST. The lymphocytes (0 min) and granulocytes (+60 min) were mainly responsible for the increase of leucocytes. Lymphocytes were significantly lower at +30 and + 60 min than before. CD3^–CD16/CD56⁺ (+480%) and CD8⁺-lymphocytes (+211%) increased at 0 min more than the other lymphocyte subpopulations (CD3+-cells, +100%; CD4⁺ cells, +56%; CD19⁺-cells, +64%). CD3^–CD16/CD56⁺-and CD8⁺-cells also were mainly responsible for the decreased values of lymphocytes at +30 min and +60 min compared to before. At 0 min naive CD8⁺ cells (CD45RA⁺, CD45RO^–) increased more than memory CD8⁺-cells (CD45RA^–, CD45RO⁺). Changes of naive and memory CD4⁺-cells did not differ. All lymphocyte subpopulations, in particular CD8⁺- and CD3^–CD16/CD56⁺-cells, decreased rapidly between 0 min and 5 min. We conclude that an intensive endurance exercise to exhaustion causes a mobilisation of lymphocytes, especially of natural killer cells (CD3^–CD16/CD56⁺) and naive, unprimed CD8+ cells (CD45RA⁺, CD45RO^–) which may be transported to injured muscles. The decreased cell numbers of the latter subpopulations are possibly one reason for the susceptibility to infections during the first hours after exercise. Furthermore, an exact definition of the intensity of exercise and times of taking blood is essential for comparing results describing cell parameters during or after exercise.     

Circulating leucocyte subpopulations in sedentary subjects following graded maximal exercise with hypoxia

Summary Ten healthy sedentary subjects [age, 27.5 (SD 3.5) years; height, 180 (SD 5) cm; mass, 69.3 (SD 6.3) kg] performed two periods of maximal incremental graded cycle ergometer exercise in a supine position. Randomly ordered and using an open spirometric system, one exercise was carried out during normoxia [maximal oxygen consumption ( O_2max)=38.6 (SD 3.5) ml·min^–1·kg^–1; maximal blood lactate concentration, 9.86 (SD 1.85) mmol·l^–1; test duration, 22.6 (SD 2.7) min], the other during hypoxia [ O_2max=33.2 (SD 3.2) ml·min^–1· kg^–1; maximal blood lactate concentration, 10.38 (SD 2.02) mmol·l^–1; test duration, 19.7 (SD 2.8) min]. At rest, immediately (0 p) and 60 min (60 p) after exercise, counts of leucocyte subpopulations (flow cytometry), cortisol and catecholamine concentrations were determined. At 0 p in contrast to normoxia, during hypoxia there was no significant increase of granulocytes. There were no significant differences between normoxia and hypoxia in the increases from rest to 0 p in counts of monocytes, total lymphocytes and lymphocyte subpopulations [clusters of differentiation (CD), CD3⁺, CD4⁺CD45RO^–, CD4⁺CD45RO⁺, CD8⁺CD45RO^–, CD8⁺CD45RO⁺, CD3⁺HLA-DR⁺, CD3^–CD16/CD56⁺, CD3⁺CD16/CD56⁺, CD 19⁺] as well as adrenaline, noradrenaline and cortisol concentrations. The counts of CD3 ^–CD16/CD56⁺-and CD8 ⁺CD45RO⁺-cells increased most. At 60 p, CD3^–CD16/CD56⁺ and CD3⁺CD16/CD56⁺-cell counts were below pre-exercise levels and under hypoxia slightly but significantly lower than under normoxia. We concluded that the exercise-induced mobilization and redistribution of most leucocyte and lymphocyte subpopulations were unimpaired under acute hypoxia at sea level. Reduced increases of granulocyte counts during the study and reduced cell numbers of natural killer cells and cytotoxic, not major histocompatibility complex-restricted T-cells, only indicated marginal effects on the immune system.     

Impact of heat exposure and moderate,intermittent exercise on cytolytic cells

This study examined the impact of heat exposure and moderate, intermittent exercise on the CD16⁺ and CD56⁺ cell counts and cytolytic activity. Eleven healthy male subjects [mean (SD): age = 27.1(3.0) years, peak oxygen intake, VO_2maxO_{2 peak} = 47.6 (6.2) ml · kg^–1 · min^–1] were assigned to each of four different experimental conditions according to a randomized-block design. While in a climatic chamber maintained at a comfortable temperature (23°C) or heated (40°C, 30% relative humidity, r.h.), subjects performed either two 30-min bouts of cycle-ergometer exercise at 50% VO_2maxO_{2 peak} (separated by a 45-min recovery interval), or remained seated for 3 h. Blood samples were analyzed for CD16⁺ and CD56⁺ cell counts, cytolytic activity and the concentrations of various exercise stress hormones (norepinephrine, epinephrine and cortisol). Heat exposure alone had no significant effect on cytolytic cells. The (CD16⁺ and CD56⁺) cell count increased significantly (P < 0.0001) during each exercise bout under both environmental conditions, but returned to baseline levels 15–45 min following each exercise bout. Total cytolytic activity (determined by a standard ⁵¹Cr release assay using K562 cells) followed a similar pattern, but cytolytic activity per CD16⁺ or CD56⁺ cell was not significantly modified by exercise. Our findings show a strong association between hemodynamic factors and recruitment of cytolytic cells into the peripheral circulation. Alterations in cytolytic activity of the whole blood during and following moderate exercise seem to be the result of changes in CD16⁺ and CD56⁺ cell counts.     

Immunological Response in Chronic Fatigue Syndrome Following a Graded Exercise Test to Exhaustion

This study was conducted to evaluate the immunological response to an exhaustive treadmill exercise test in 20 female chronic fatigue syndrome patients compared to 14 matched sedentary controls. Venipuncture was performed at baseline and 4 min, 1 hr, and 24 hr postexercise. White blood cells were labeled for monoclonal antibody combinations and were quantified by FACsan. Cytokines were assayed utilizing quantitative RT/PCR. No group difference was seen in (28.6 ± 1.6 vs 30.9 ± 1.2 ml · kg^–1 · min^–1; P > 0.05). However, 24 hr after exercise the patients' fatigue levels were significantly increased (P < 0.05). The counts of WBC, CD3⁺CD8⁺ cells, CD3⁺CD4⁺ cells, T cells, B cells, natural killer cells, and IFN- changed across time (P's < 0.01). No group differences were seen for any of the immune variables at baseline or after exercise (P's > 0.05). The immune response of chronic fatigue syndrome patients to exhaustive exercise is not significantly different from that of healthy nonphysically active controls.     

Cell numbers and in vitro responses of leucocytes and lymphocyte subpopulations following maximal exercise and interval training sessions of different intensities

Summary In vitro lymphocyte function and the mobilisation of peripheral blood leucocytes was examined in eight trained subjects who undertook an incremental exercise test to exhaustion and a series of interval training sessions. Venous blood samples were obtained before the incremental test, immediately after, and 30, 60, and 120 min after the test. Interval training sessions were undertaken on separate days and the exercise intensities for each of the different sessions were 30%, 60%, 90% and 120% of their maximal work capacity respectively, as determined from the incremental exercise test. There were 15 exercise periods of 1-min duration separated by recovery intervals of 2 min in each session. Venous blood samples were obtained immediately after each training session. Significant increases in lymphocyte subpopulations (CD3⁺, CD4⁺, CD8⁺, CD20⁺, and CD56⁺) occurred following both maximal and supramaximal exercise. This was accompanied by a significant decrease in the response of cultures of peripheral blood lymphocytes to Concanavalin A (ConA), a T-cell mitogen. The state of lymphocyte activation in vivo as measured by CD25⁺ surface antigen was not, however, affected by acute exercise. The total number of lymphocytes, distribution of lymphocyte subpopulations and in vitro lymphocyte response to ConA had returned to pre-exercise levels within half an hour of termination of exercise but serum cortisol concentrations had not begun to fall at this time. There was a significant decrease in the CD4⁺:CD8⁺ cell ratio following exercise; this was more the result of increases in CD3^–CD8⁺ cells (CD8⁺ natural killer cells) than to CD3⁺CD8⁺ cells (CD8⁺ T-lymphocytes). Decreased responsiveness of T-cells to T-cell mitogens, postexercise, may have been the result of decreases in the percentage of T-cells in postexercise mixed lymphocyte cultures rather than depressed cell function. The cause of this was an increase in the percentage of natural killer cells which did not respond to the T-cell mitogen. The results indicated that while a substantial immediate in vitro immunomodulation occurred with acute exercise, this did not reflect an immunosuppression but was rather the result of changes in the proportions of reactive cells in mononuclear cell cultures. We have also demonstrated that the degree of the change in distribution of lymphocyte subpopulation numbers and responsiveness of peripheral blood mononuclear cells in in vitro mitogen reactions increased with increasing exercise intensity. Plasma volume changes may have contributed to some of the changes seen in leucocyte population and subpopulation numbers during and following exercise.     

Human Immunodeficiency Virus Type 1 Replication,Immune Activation, and Circulating CytotoxicT Cells Against Uninfected CD4+ T Cells

Cytotoxic T lymphocytes (CTL) that kill uninfected activated CD4⁺ T cells can be induced in vitro by stimulating CD8⁺ T cells with activated autologous CD4⁺ T cells. Similar CTL have been detected in circulating T cells from human immunodeficiency virus type 1 (HIV)-infected individuals. To define the in vivo correlates of this CTL activity, we studied plasma -2 microglobulin and HIV RNA levels, T-lymphocyte subset counts, and expression of CD28 on CD8⁺ T cells concurrently with circulating CTL activity against uninfected CD4⁺ T cells in 75 HIV-infected individuals at different stages of disease progression. Mean values of each parameter were compared in subsets of this group of 75 segregated on the basis of this CTL activity. The group with CTL against uninfected activated CD4⁺ T lymphocytes had more CD8⁺ T cells, a higher percentage of CD28^– CD8⁺ T cells, and higher plasma levels of HIV RNA and -2 microglobulin. CTL against uninfected activated CD4⁺ T cells were predominantly CD28^– and in HIV-infected individuals were associated with immunological or virological evidence of progressive disease. In HIV infection, circulating CTL activity against uninfected activated CD4⁺ T lymphocytes is associated with immune activation, CD8⁺ T cell expansion, accumulation of CD28^– CD8⁺ T cells, and inadequate suppression of HIV replication.     

Effects of moderate endurance exercise and training on in vitro lymphocyte proliferation,interleukin-2 (IL-2) production,and IL-2 receptor expression

This study was designed to examine immunological responses to an acute bout of cycle ergometry exercise before and after moderate endurance training. Previously sedentary males were randomly assigned to matched training (n=9) or control (n=6) groups. Training comprised 12 weeks during which supervised cycle ergometer exercise took place [30 min at 65–70% of maximal oxygen intake , 4–5 days · week^–1]. An acute bout of exercise (60 min; 60% was performed initially and after the 12-week interval. Samples of peripheral venous blood were taken at rest, after 30 and 60 min of exercise, and at 30 and 120 min post-exercise. Training improved by an average of 20% (40.6 to 49.2 ml · kg^–1 · min^–1). Relative to baseline and control measures, the resting concentration of (CD3-CD16⁺/CD56⁺) natural killer (NK) cells increased by 22% (P<0.05). The resting count of total CD25⁺ [interleukin-2 receptor (IL-2R) chain] lymphocytes did not change following training, but dual staining analysis showed a 100% increase in the fraction of CD16⁺ CD25⁺ NK cells (P < 0.05). Likewise the resting CD122⁺ (IL-2R chain) lymphocyte count increased 35% after training, the greatest increases (44%) being in CD16⁺ CD122⁺ NK cells (P<0.05). Soluble IL-2R levels also increased 33% (P< 0.05) after training. Following acute exercise at the same relative intensity; trained individuals exhibited a larger increase in the NK cell count, reduced lymphocytopenia, and attenuation of exercise-induced suppression of lymphocyte proliferation and IL-2 production (P<0.05). In addition, smaller increases in CD4 and CD8 counts during exercise were noted, but with faster recovery post-exercise (P<0.05). Addition of recombinant IL-2 (rIL-2) to phytohemagglutinin-stimulated peripheral blood mononuclear cell cultures did not reverse exercise-induced suppression of cell proliferation, either before or after training. However, rIL-2 did augment the spontaneous blastogenesis of exercise and post-training samples relative to baseline (P < 0.05). We conclude that moderate endurance training is associated with sustained alterations in immune function, both at rest and when exercising. Further investigations are necessary to determine the impact on overall health and susceptibility to disease.     

Cellular effects ofβ-adrenergic and of cAMP stimulation on potassium transport in rat alveolar epithelium

Alveolar fluid absorption is greatly enhanced by cAMP and by -adrenergic agonists via an increase in Na⁺ transport. Little is known about K⁺ homeostasis under these circumstances. We studied K⁺ transport across alveolar epithelium in isolated perfused rat lungs stimulated either by dibutyryl-cAMP or isoproterenol. K⁺ fluxes and the apparent permeability of⁸⁶Rb across the epithelium (alveoli to plasma) were interpreted according to a model involving two types of cells, B and L, distinguished by the location of Na⁺–K⁺-ATPases (basal and luminal). Water is considered to be absorbed by B cells in a solute-coupled process energized by a basolateral Na⁺–K⁺-ATPase that is stimulated by isoproterenol and cAMP. K⁺ transport out of the alveoli is due to the activity of a Na⁺–K⁺-ATPase located in the apical membrane of L cells. In the present study net transport rate of K⁺ was –0.5±0.15 nmol/s,n=20 (out of alveoli) in control conditions. When the epithelium was stimulated by dibutyryl-cAMP (10^–4 mol/l) net absorption of K⁺ reversed to net secretion into alveoli (3.2±0.31 nmol/s), fluid absorption was not stimulated. K⁺ secretion was abolished by apical Ba²⁺, indicating it was due to opening of apical K⁺ channels. Basolateral ouabain reversed net K⁺ secretion to net absorption indicating that K⁺ entry into alveoli was dependent on activity of B cell basolateral Na⁺–K⁺-ATPase (masking simultaneous K⁺ removal by apical L cell Na⁺–K⁺-pump). When larger concentrations of dibutyryl-cAMP (10^–3 mol/l) or when isoproterenol were used to stimulate the epithelium there was a tripling of fluid absorption. In this situation a biphasic response of K⁺ transport was observed. Initially, net K⁺ influx similar to that observed in 10^–4 mol/l dibutyryl-cAMP experiments occurred, followed by a large K⁺ efflux from alveolar spaces. This may reflect stimulation of apical Na⁺–K⁺-ATPase in L cells, combined with partial closure of apical K⁺ channels in B cells. The variations of the apparent permeability of⁸⁶Rb, measured from alveoli to plasma, reinforce this interpretation of the mechanisms of K⁺ transport. Our results suggest that K⁺ transport across alveolar epithelium is modulated by isoproterenol and cAMP, by stimulation of Na⁺–K⁺-ATPase in B and L cells supplemented by control of K⁺ channels.     

Differential mobilization of leucocyte and lymphocyte subpopulations into the circulation during endurance exercise

Summary A total of 14 healthy subjects [means (SD): 27.6 (3.8) years; body mass 77.8 (6.6) kg; height 183 (6) cm] performed endurance exercise to exhaustion at 100% of the individual anaerobic threshold (Th_an) on a cycle ergometer (mean workload 207 (55) W; lactate concentrations 3.4 (1.2) mmol · l^–1; duration 83.8 (22.2) min, including 5 min at 50% of individual Th_an). Leucocyte subpopulations were measured by flow cytometry and catecholamines by radioimmunological methods. Blood samples were taken before and several times during exercise. Values were corrected for plasma volume changes and analysed using ANOVA for repeated measures. During the first 10 min of exercise, of all cell subpopulations the natural killer cells (CD3^–CD16/CD56+) increased the most (229%). Also CD3^÷CD16/CD56+ (84%), CD8^÷CD45RO^– (69%) cells, eosinophils (36%) and monocytes (62%) increased rapidly during thattime.CD3⁺, CD3⁺HLA-DR⁺, CD4⁺CD45RO⁺, CD4⁺CD45RO^–, CD8⁺CD45RO^÷ and CD19⁺ cells either did not increase or increased only slightly during exercise. Adrenaline and noradrenaline increased nearly linearly by 36% and 77% respectively at 10 min exercise. The increase of natural killer cells and heart rates between rest and 10 min of exercise correlated significantly (r=0.576,P=0.031). We conclude that natural killer cells, cytotoxic, non-MHC-restricted T-cells, monocytes and eosinophils are mobilized rapidly during the first minutes of endurance exercise. Both catecholamines and increased blood flow are likely to contribute this effect.     

The effects of incremental submaximal exercise on circulating leukocytes in physically active and sedentary males and females

To study the effects of exercise on circulating leukocytes and leukocyte subsets, physically active (n = 32) and sedentary (n = 32) male and female subjects were randomly assigned to an exercise or control condition. Exercise involved a continuous incremental protocol consisting of cycling for three periods of 6 min at power outputs corresponding to 55%, 70% and 85% maximal oxygen uptake ( . Blood samples were drawn from a venous catheter at baseline, and at 6 min, 12 min, and 18 min after beginning the exercise and 2 h following completion of exercise. Resting- and exercise-induced alterations in total leukocytes were independent of gender and subject fitness level. Relative to baseline, each increment in workload resulted in a rapid increase in the number of circulating leukocytes. Increases in neutrophils, lymphocytes and monocytes accounted for the exercise-induced leukocytosis. With regard to lymphocytes, exercise resulted in a significant increase in the number of T cells (CD3⁺), T helper cells (CD4⁺), T suppresser (CD8⁺) and natural killer (NK) cells (CD3^–/CD16⁺/CD56⁺). The largest percentage increase occurred in the NK cell population. The CD4⁺: CD8⁺ ratio decreased (P < 0.001) throughout exercise due to a larger increase in the number of CD8⁺ cells relative to CD4⁺ cells. An exercise-induced neutrophilia, lymphocytopenia, and eosinophelia was observed 2 h into recovery. Exercise resulted in significant increases in plasma epinephrine and norepinephrine levels. There was no indication of a hypothalamic-pituitarty-adrenal response during exercise. The results indicate that the rapid, albeit transient, alteration in the number of circulating leukocytes during and following an acute progressive incremental exercise test are independent of gender and fitness.     

The effects of altered exercise distribution on lymphocyte subpopulations

The effects of exercise distribution on lymphocyte count, lymphocyte subpopulations and plasma cortisol concentration in peripheral blood were assessed in 19 healthy subjects. The subjects were randomly divided into group A (n = 10) or group B (n = 9) according to exercise distribution. Both groups underwent a 10-week programme involving 5 × 2-week blocks: baseline (B), training period 1 (TP1), stabilisation 1 (S1), training period 2 (TP2), and stabilisation 2 (S2). During B, S1 and S2 normal training was undertaken. During TP1 and TP2 the subjects increased the amount of training by 50% in week 1 and by 100% in week 2. During TP1 subjects in group A exercised 6 days·week^–1, while during TP2 these subjects exercised on 3 alternate days·week^–1, but doubled the duration of each training session. The subjects in group B reversed this training order. Blood was collected 36–42 h following exercise period B, and at the end of periods TP1, S1, TP2 and S2, and also 12–18 h following completion of exercise at the end of TP1 and TP2. There were no significant differences (P > 0.05) between the 6 day·week^–1 programme and the 3 alternate day·week^–1 programme in total lymphocyte count, CD3⁺, CD4⁺, CD8+, CD16⁺, or CD19⁺ cells, the CD4:CD8 ratio, HLA-DR⁺ (activated) T cells or plasma cortisol concentrations. Following both TP1 and TP2 there was a nonsignificant decrease in lymphocyte subpopulations. However following both S1 and S2 (baseline training) there was a significant increase in total lymphocyte count, CD3⁺, CD4⁺ and CD8⁺ lymphocytes. The S2 variables statistically significant from B were: total lymphocyte count (P < 0.01), CD3⁺ T-cells and percentage of circulating lymphocytes (^P < 0.01), CD4⁺ cells (P < 0.0001), CD8⁺ cells (P < 0.05), and HLA-DR⁺ (activated) T-cells (P < 0.05). The results indicated that provided the amount of exercise is constant for a given period, then exercise distribution is not a critical variable in the alteration of lymphocyte subpopulations that may occur in response to overload training. However 2 weeks of overload training followed by 2 weeks of active recovery (baseline) training may induce an increase in the lymphocyte count.     

cAMP-dependent activation of small-conductance Cl− channels in HT29 colon carcinoma cells

The present study was performed to examine the conductance properties in the colon carcinoma cell line HT₂₉ and the activation of Cl^– channels by cAMP. A modified cell-attached nystatin patch-clamp technique was used, allowing for the simultaneous recording of the cell membrane potential (PD) and the conductance properties of the cell-attached membrane. In resting cells, PD was –56±0.4 mV (n=294). Changing the respective ion concentrations in the bath indicate that these cells possess a dominating K⁺ conductance and a smaller Cl^– conductance. A significant non-selective cation conductance, which could not be inhibited by amiloride, was only observed in cells examined early after plating. The K⁺ conductance was reversibly inhibited by 1–5 mmol/l Ba²⁺. Stimulation of the cells by the secretagogues isoproterenol and vasointestinal polypeptide (VIP) depolarized PD and induced a Cl^– conductance. Similar results were obtained with compounds increasing cytosolic cAMP: forskolin, 3-isobutyl-1-methylxanthine, cholera toxin and 8-bromoadenosine cyclic 3,5-monophosphate (8-Br-cAMP). VIP (1 nmol/l, n=10) and isoproterenol (1 umol/l, n=12) depolarized the cells dose-dependently and reversibly by 12±2 mV and 13±2 mV. The maximal depolarization was reached after some 20 s. The depolarization was due to increases in the fractional Cl^– conductance. Simultaneously the conductance of the cellattached membrane increased from 155±31 pS to 253±40 pS (VIP, n=4) and from 170±43 pS to 268±56 pS (isoproterenol, n=11), reflecting the gating of Cl^– channels in the cell-attached membrane. 5-Nitro-2-(3-phenylpropylamino)-benzoate (1 mol/l) was without significant effects in resting and in forskolin-stimulated HT₂₉ cells. The agonist-induced conductance increase of the cell-attached nystatin patches was not paralleled by the appearance of detectable single-channel events in these membranes. These data suggest activation of small, non-resolvable Cl^– channels by cAMP.Supported by DFG Gr 480/10 and BMFT 01 GA 88/6     

Threshold increases in plasma growth hormone in relation to plasma catecholamine and blood lactate concentrations during progressive exercise in endurance-trained athletes

Plasma human growth hormone ([HGH]), adrenaline ([A]), noradrenaline ([NA]) and blood lactate ([La^–]_b) concentrations were measured during progressive, multistage exercise on a cycle ergometer in 12 endurance-trained athletes [aged 32.0 (SEM 2.0) years]. Exercise intensities (3 min each) were increased by 50 W until the subjects felt exhausted. Venous blood samples were taken after each intensity. The [HGH] and catecholamine concentrations increased negligibly during exercise of low to moderate intensities revealing an abrupt rise at the load corresponding to the lactate threshold ([La^–]-T). Close correlations (P < 0.001) were found between [La^–]_b and plasma [HGH] (r = 0.64), [A] (r = 0.71) and [NA] (r = 0.81). The mean threshold exercise intensities for [HGH], [A] and [NA], detected by log-log transformation, [154 (SEM 19) W, 162 (SEM 15) W and 160 (SEM 17) W, respectively] were not significantly different from the [La^–]-T [161 (SEM 12) W]. The results indicated that the threshold rise in plasma [HGH] followed the patterns of plasma catecholamine and blood lactate accumulation during progressive exercise in the endurancetrained athletes.     

Primed and naive helper T cells in labial glands from patients with Sjogren's syndrome

Summary This study has investigated the presence and distribution of B cells, T cells and T-cell subsets within labial glands of patients with primary Sjogren's syndrome (n=9) and secondary Sjogren's syndrome associated with rheumatoid arthritis (n=8) using a sequential double immunoperoxidase technique and true colour image analysis. The composition of the inflammatory infiltrates was similar in glands from both patient groups. B cells were normally present within large foci with few detected in diffuse infiltrates such that the ratio of TB cells in foci (2.41) was significantly lower than in diffuse infiltrates (7.31; P<0.001). In all infiltrates helper T cells (CD8^–, CD3⁺) predominated over suppressor/cytotoxic cells (CD8⁺, CD3⁺; 2.71). Analysis of primed (CD45RA^–, CD45RO⁺) and naive (CD45RA⁺, CD45RO^–) CD8^– T cells showed that the ratio of the primed to naive subset was significantly higher in focal (4.21) compared to diffuse (1.51;P< 0.001) areas of lymphoid infiltration. These results indicate that the focal lymphocytic infiltrates characteristic of Sjogren's syndrome contain B cells associated with a T-cell population consisting predominantly of primed CD8^– helper T cells. This latter population may be responsible for upregulating glandular B-cell activity in Sjogren's syndrome.     

Exercise-induced alterations in natural killer cell number and function

To study the effects of exercise on natural killer (NK) cell number and activity (NKCA) healthy male (n = 32) and female (n = 32) subjects were randomly assigned to an exercise or control condition. Exercise involved a continuous incremental protocol consisting of cycling for three periods of 6 min at work rates corresponding to 55%, 70% and 85% peak oxygen uptake ( ). Blood samples were drawn at baseline, at 6 min, 12 min and 18 min during exercise, and at 2 h following completion of exercise. Relative to both baseline and control conditions, exercise resulted in an increase in the number of circulating lymphocytes. The proportion of T cells (CD3⁺) and B cells (CD19 ⁺) significantly decreased, and NK cells (CD3^–CD16⁺CD56⁺) increased throughout exercise. NKCA increased (P < 0.001) during the initial 6 min of exercise with no further changes observed, despite increases (P < 0.001) in the number and proportion of circulating NK cells during exercise at 70% and 85% . Plasma epinephrine and norepinephrine increased (P < 0.001) above baseline at 12 min and 18 min. The changes in NK cell number and function were independent of gender. The results indicate that short-duration low-intensity exercise can significantly increase NK cell number and activity. However, alterations in NK cell number are not accompanied by changes of a similar magnitude in NKCA.     

Effects of hydration state on plasma testosterone,cortisol and catecholamine concentrations before and during mild exercise at elevated temperature

This investigation examined the influence of pre-exercise hydration status, and water intake during low intensity exercise (5.6 km · h^–1 at 5% gradient) in the heat (33° C), on plasma testosterone (TEST), cortisol (CORT), adrenaline (A), and noradrenaline (NA) concentrations at baseline (BL), pre-exercise (PRE), and immediately (IP), 24 h (24 P), and 48 h postexercise (48 P). Ten active men participated in four experimental treatments. These treatments differed in preexercise hydration status [euhydrated or hypohydrated (HY, –3.8 (SD 0.7)% body mass)] and water intake during exercise (water ad libitum or no water intake during exercise, NW). There were no significant changes in TEST, CORT, or A concentrations with time (BL, PRE, IP, 24 P, and 48 P), or among treatments. However, significant increases from BL and PRE plasma NA concentrations were observed at IP during all four treatment conditions. In addition, HY + NW resulted in significantly higher plasma NA concentrations at IP compared to all other treatments. These results suggest that moderate levels of hypohydration during prolonged, low intensity exercise in the heat do not influence plasma TEST, CORT, or A concentrations. However, plasma NA appears to respond in a sensitive manner to these hydration and exercise stresses.     

Effect of acute mild hypoxia during exercise on plasma free and sulphoconjugated catecholamines

Catecholamine (CA) response to hypoxic exercise has been investigated during severe hypoxia. However, altitude training is commonly performed during mild hypoxia at submaximal exercise intensities. In the present study we tested whether submaximal exercise during mild hypoxia compared to normoxia leads to a greater increase of plasma concentrations of CA and whether plasma concentration of catecholamine sulphates change in parallel with the CA response. A group of 14 subjects [maximal oxygen uptake, 62.6 (SD 5.2) ml · min^–1 · kg^–1 body mass] performed two cycle ergometer tests of 1-h duration at the same absolute exercise intensities [191 (SD 6) W] during normoxia (NORM) and mild hypoxia (HYP) followed by 30 min of recovery during normoxia. Mean plasma concentrations of noradrenaline ([NA]), adrenaline ([A]), and noradrenaline sulphate ([NA-S]) were elevated (P < 0.01) after HYP and NORM compared with mean resting values and were higher after HYP [20.9 (SEM 3.1), 2.2 (SEM 0.24), 8.12 (SEM 1.5) nmol · 1^–1, respectively] than after NORM [(13.7 (SEM 0.9), 1.5 (SEM 0.14), 6.8 (SEM 0.7) nmol · 1^–1, respectively P < 0.01]. The higher plasma [NA-S] after HYP (P < 0.05) were still measurable after 30 min of recovery. From our study it was concluded that exercise at the same absolute submaximal exercise intensity during mild hypoxia increased plasma CA to a higher extent than during normoxia. Plasma [NA-S] response paralleled the plasma [NA] response at the end of exercise but, in contrast to plasma [NA], remained elevated until 30 min after exercise.