Effect of exercise training on leukocyte subpopulations and clinical course in cardiac transplant patients.
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Research on consolidation of long-term memory suggests that acute immune system activation induced by endotoxin lipopolysaccharide (LPS) may disrupt consolidation of newly acquired learning. Adult male Sprague-Dawley rats were trained to perform a simple Y-maze task and were immediately afterwards administered LPS (15 microg/kg) or saline. After a seven-day interval, subjects were returned to the Y-maze and were retrained to criterion. It was found that subjects treated with saline required significantly fewer trials to relearn the task relative to the LPS group and a no-partial-learning control group, which themselves did not differ. These results are most readily explained in terms of a disruptive effect of acute immune system activation on consolidation of newly induced acquired memories.
The term "neural network" has been applied to arrays of simple activation units linked by weighted connections. If the connections are modified according to a defined learning algorithm, such networks can be trained to store and retrieve patterned information. Memories are distributed throughout the network, allowing the network to recall complete patterns from incomplete input (pattern completion). The major biological application of neural network theory to date has been in the neurosciences, but the immune system may represent an alternative organ system in which to search for neural network architecture. Previous applications of parallel distributed processing to idiotype network theory have focused upon the recognition of individual epitopes. We argue here that this approach may be too restrictive, underestimating the power of neural network architecture. We propose that the network stores and retrieves large, complex patterns consisting of multiple epitopes separated in time and space. Such a network would be capable of perceiving an entire bacterium, and of storing the time course of a viral infection. While recognition of solitary epitopes occurs at the cellular level in this model, recognition of structures larger than the width of an antibody binding site takes place at the organ level, via network architecture integration of, i.e. individual epitope responses. The Oudin-Cazenave enigma, the sharing of idiotypic determinants by antibodies directed against distinct regions of the same antigen, suggests that some network level of integration of the individual clonal responses to large antigens does occur. The role of cytokines in prior neural network models of the immune system is unclear. We speculate that cytokines may influence the temperature of the network, such that changes in the cytokine milieu serve to "anneal" the network, allowing it to achieve the optimum steady-state in the shortest period of time.
Epidemiological evidence suggests that heavy acute or chronic exercise is related to an increased incidence of upper respiratory tract infections in athletes, while moderate exercise is believed to be protective. During the past years, many groups have investigated the association between changes within the immune system and exercise at different intensity levels. Although following strenuous exercise, some immunologic alterations were quite consistent and reproducible, e.g. neutrophilia, lymphopenia, and depression of natural killer cell activity, some findings were divergent or strongly dependent on the study design and athletes investigated. Lately, interesting results in the field of psychoneuroimmunolgy as well as new insights in the relationship between macro- and micronutrient and the immune system have brought up new fields of research interest. There is growing evidence that e.g. lifestyle factors, the coping with daily stress, and dietary behavior are important cofactors in the immune response to exercise. The present work gives a short review on the literature dealing with URTI in athletes with special reference to the above mentioned cofactors. In addition, the results of a recent investigation concerning training and associated lifestyle patterns in German athletes are presented.
BACKGROUND: Esophageal squamous cell carcinoma (ESCC) lacks reliable prognostic biomarkers. Homologous recombination deficiency (HRD) has been implicated in genomic instability across multiple cancers, but its prognostic significance in ESCC remains unexplored. This study aimed to evaluate HRD score as a prognostic biomarker and develop a machine learning-based predictive model for ESCC. METHODS: Transcriptomic and clinical data from 78 ESCC patients were obtained from The Cancer Genome Atlas (TCGA) and randomly split into training (70%) and test (30%) cohorts. Prognostic models were constructed using 112 machine learning algorithm combinations based on DNA damage response (DDR)-related genes. Gene set enrichment analysis (GSEA), somatic mutation profiling, and immune cell infiltration estimation via CIBERSORT were performed to characterize HRD-associated molecular features. RESULTS: High HRD scores were significantly associated with poorer overall survival (P<0.05). Among 112 algorithm combinations, the survival support vector machine (Survival-SVM) model demonstrated optimal performance [training concordance index (C-index): 0.741; test C-index: 0.708], identifying six hub genes: PARP1, MBD4, TELO2, NSMCE3, SMUG1, and BABAM1. A nomogram incorporating risk score (RS) and clinical variables achieved strong predictive accuracy for 1- to 3-year survival [area under the curve (AUC) >0.7]. High-HRD tumors exhibited distinct mutational patterns (TP53 and TTN) and enriched glutathione metabolism and cytochrome P450 pathways. Immune infiltration analysis revealed significant differences in plasma cell and neutrophil infiltration between risk groups (P<0.05), suggesting HRD-associated immune microenvironment remodeling. CONCLUSIONS: We developed a novel HRD-based prognostic model incorporating six DDR-related genes that demonstrates robust predictive performance in ESCC. HRD score is identified as an independent prognostic factor associated with genomic instability, immune microenvironment alterations, and clinical outcomes. These findings provide a theoretical basis for personalized treatment strategies, including potential applications of PARP inhibitors and immunotherapy in ESCC.
The effect of propranolol, a beta-adrenergic receptor antagonist, on the suppression of splenic mitogenic responsiveness induced by an aversive conditioned stimulus (CS) was evaluated in rats. Experiment 1 demonstrated that propranolol administration before presentation of the CS completely blocked the suppressive effect. In contrast, Experiment 2 showed that administration of propranolol during the training of the aversive CS had no effect on the suppressive effect of the CS in a subsequent test. These findings indicate that the release of catecholamines is responsible for the conditioned immune alteration of splenic lymphocytes. Taken further, these findings suggest that the learning of the conditioned immunomodulatory response to an aversive CS is a Pavlovian conditioning process that is not dependent on the performance of the conditioned response during training.
The future role of the allergist/immunologist is dictated by current training and research, which promise to broaden the expertise of practitioners of this discipline. Specialists in allergy and immunology are certified by the American Board of Allergy and Immunology following specialized training in allergic diseases, clinical immunology, procedural skills, clinical principles and analytic methods, clinical laboratory test proficiency, and research. The expanding role of clinical immunology in the management of multiple diseases suggests that specialists in allergy and immunology will continue to broaden their expertise in the care of disorders with an immune component. The discipline of allergy and immunology offers a number of career advantages in both the practice of allergy and immunology and in the application of training in allergy and immunology to opportunities in the pharmaceutical industry and academics. Manpower assessments suggest that the number of allergists and immunologists in training are insufficient to meet the current needs.
20 young male track and field runners (400 m-3000 m) with a 4 mmol/l lactic acid threshold of x = 4.97 +/- 0.35 m/s were tested after three different training periods: 1. at the end of a two month endurance training, practised nearly every day; 2. after a period of speed and strength training, which was specific with respect to their discipline, with anaerobic lactic energy production up to 15 mmol/l lactic acid; 3. during the competition period. The blood samples were taken at rest (4 p.m.) and 22 hrs after the last exercise. On the cell surface the antigens CD3+, CD20+CD23+, CD4+HLADR, CD4+CD25+, CD8+CD28+, CD4+CD45RO+, CD16+CD56+, CD54+ and in the blood serum the concentrations of s-IL-2-R, s-ICAM-1 were analysed. 13 students of physical education served as a control group. The main results were: Only at the end of the endurance training period (1) an increase of s-ICAM-1 was found, which may be interpreted as a protective mechanism against infections. Compared with the control group CD20+CD23+ antigen was constantly elevated and during the transition from the training to the competition period the CD4+CD45RO+ subset increased. These results may provide evidence for a connection to a susceptibility to allergic disease and to overtraining. Furthermore, an activation of the specific immune system was indicated by an elevation of the s-IL-2-R and an activation of the monocytic-phagocytic system was shown by increased levels of ICAM-1. The importance of these results for the training process and with regard to susceptibility to infections is discussed.
BACKGROUND: Aging is associated with decline in both cell-mediated and humoral immunity and may contribute to increased incidence and severity of infections in frail elderly. Exercise, depending on intensity, has significant effects on the immune system. We conducted a randomized, controlled clinical trial of a 32-week functionally oriented exercise program in frail elderly living in nursing homes and determined whether the exercise intervention was associated with a change in immune parameters in this frail elderly nursing home population. METHODS: Nursing home residents were randomly assigned to an intervention (n = 94) and control group (n = 96). The intervention consisted of a functionally oriented endurance and resistance exercise training that was provided every 2 hours from 8:00 AM to 4:00 PM for 5 days a week for 8 months. Lymphocyte subpopulations, including activation markers (CD28, CD25, HLA-DR), in vitro proliferation, and soluble products of cytokine activity (neopterin and sTNF-RII) in serum were measured by taking blood samples at baseline and after 8 weeks and 32 weeks of the intervention. RESULTS: Exercise training did not induce changes in lymphocyte subpopulations, activation markers (CD28, CD25, HLA-DR), in vitro proliferation, and soluble products of cytokine activity (neopterin and sTNF-RII) in serum. CONCLUSIONS: A 32-week exercise intervention did not bring about beneficial or detrimental effects on immune parameters in the frail elderly nursing home population and may explain why the intervention was not associated with a change in the incidence of infections in the intervention group compared with the control group.
The appropriate operation of a radial basis function (RBF) neural network depends mainly upon an adequate choice of the parameters of its basis functions. The simplest approach to train an RBF network is to assume fixed radial basis functions defining the activation of the hidden units. Once the RBF parameters are fixed, the optimal set of output weights can be determined straightforwardly by using a linear least squares algorithm, which generally means reduction in the learning time as compared to the determination of all RBF network parameters using supervised learning. The main drawback of this strategy is the requirement of an efficient algorithm to determine the number, position, and dispersion of the RBFs. The approach proposed here is inspired by models derived from the vertebrate immune system, that will be shown to perform unsupervised cluster analysis. The algorithm is introduced and its performance is compared to that of the random, k-means center selection procedures and other results from the literature. By automatically defining the number of RBF centers, their positions and dispersions, the proposed method leads to parsimonious solutions. Simulation results are reported concerning regression and classification problems.
OBJECTIVES: To assess immunization practices and attitudes of U.S. primary care physicians regarding adult influenza and pneumococcal immunizations. METHODS: Mailed survey of primary care internists and family physicians across the United States; four follow-up contacts by mail and telephone. Bivariate and multivariate analyses assessed immunization practices and attitudes and differences by physician characteristics. RESULTS: Three hundred and sixteen of 668 eligible physicians responded (50 refused, response rate of 266 = 40%); 220 provided adult vaccinations. More than 64% indicated they routinely vaccinated patients >/=65 years and those <65 years with chronic disease indications with both influenza and pneumococcal vaccine. Reported barriers for influenza vaccination included vaccine safety concerns by patients (58%), urgent concerns dominating visits (43%), and inadequate reimbursement (26%). Reported barriers for pneumococcal vaccination included urgent concerns during office visits (44%), no patient immunization history (36%), patient concerns about vaccine safety (31%), and inadequate reimbursement (25%). Many physicians indicated willingness to try tracking systems (72%), chart reminders (55%), patient reminders (53%), standing orders (36%), external lists of unimmunized patients for pneumococcal vaccination (74%), external patient reminders (70%), and office training of physicians (36%) or staff (46%). CONCLUSIONS: While most physicians favored adult vaccinations, practical barriers to vaccination exist. Most physicians would adopt evidence-based strategies to improve immunization delivery.
When exploring the possible mechanisms by which adaptation to physical exercise can occur, the immune system appears to be a likely candidate of importance, because physical exercise will exert both systemic and local effects on the immune system. This review will focus on the immune system in the perspective of skeletal muscle tissue adaptation to physical exercise. The involvement of circulating and tissue bound leukocytes, cytokines, hormones and growth factors will be discussed. A few new hypotheses are presented: 1) The primary mechanism governing skeletal muscle adaptation to physical exercise is suggested to be of non-inflammatory origin; 2) it is suggested that IL-10 may function as one of the signals transmitted by skeletal muscle cells when substrate levels are low; 3) creatine kinase could have immuno-modulatory actions, thereby serving as a messenger molecule between skeletal muscles and the immune system. Based on the intricate and complex array of events governing life and death in other cells types, a simple explanation of the issues of skeletal muscle development, regeneration and adaptation is unlikely. There are large individual differences in the immune response to the same relative or absolute exercise intensity, suggesting that interpreting the average effect of exercise on a group of individuals may not reveal the cause and effect of any given immunological variable. More sophisticated analyses of collected data is suggested in future studies and perhaps some re-evaluation of existing data is also needed. If we can understand the mechanisms behind muscle adaptation, we can also optimize training programs and athletic performance.
Considering experience acquired in the past years, it seems as though physicians have reached a plateau in the frequency of peritonitis. A peritonitis rate of 1 every 2 patient years may be acceptable. Further reduction of this peritonitis rate will require inordinately large efforts on all fronts. One will have to consider what are the acceptable costs and risks of peritonitis in patients on peritoneal dialysis. New developments in catheter technology, improved connections, better understanding of patient selection and training programs, improved diagnostic and therapeutic methods in the management of peritonitis, and understanding of the infectious and immune processes are eagerly awaited developments.
A seroepidemiologic surveillance of rubella infections in arriving male and female Navy recruits indicated that from 82-90% of young adults have hemagglutination (HA) titers of 1:10 or greater. Subsequent to the establishment of a new male recruit camp, there was a 10- to 11-month hiatus of low level rubella infection in the population. Once endemic rubella was established, more than 73.3 per cent of those with no detectable initial titer seroconverted. There was no reported rubella infection at an isolated female recruit camp of about 500 women even though the proportion of susceptibles was similar. However, once the female recruit camp was relocated within the male camp, their experience with rubella became comparable. A small (6.8% men, 5.6% women) number of recruits with pre-existing HA antibody titers had a four-fold or greater rise in titer during training. The great transmissibility of rubella virus in a closed population was illustrated and the ineffectiveness of herd immunity in this setting was evident.
PURPOSE: Long-term intensive exercise by athletes may sometimes lead to a susceptibility to infections. In the present study, we examined the differences in immune function between amateur wrestlers experiencing weight loss (WL) and those without WL who underwent similar intensive exercise training. METHODS: Eighteen elite amateur wrestlers who attended the Japanese national championship were classified into two groups. One group consisted of those with either slight or no WL (without WL) (<4%; mean, 1%) (N = 9), and the other group consisted of those who needed a significant WL (with WL) (> or = 4%; mean, 7%) (N = 9) during a 1-month period of intensive training. The leukocyte counts as well as the leukocyte subsets in the peripheral blood were examined. The proliferation and cytokine production in T lymphocytes in response to bacterial superantigens (staphylococcal enterotoxin B, streptococcal pyrogenic exotoxin A) and anti-CD3 antibody (Ab) were also examined. RESULTS: The total leukocyte counts and leukocyte subsets did not differ substantially between the groups and were also not different from the findings before starting the intensive exercise training. Natural killer cells and T cells among the lymphocytes significantly increased in both groups, whereas the increase in each group was not different. Although the T-cell responses to bacterial superantigens were not different, the anti-CD3 Ab-stimulated proliferation and interferon-gamma production of lymphocytes from the wrestlers with WL were significantly lower than those of the wrestlers without WL. This hyporesponsiveness to CD3 stimulation recovered 2 months after the tournament when the wrestlers reverted to their normal weight. CONCLUSION: Intensive exercise in athletes accompanied by a rapid WL was found to compromise the CD3/T-cell receptor-mediated T-cell function in athletes.
This study extended to treadmill exercise training our prior report (Dishman RK, Warren JM, Youngstedt SD, Yoo H, Bunnell BN, Mougey EH, Meyerhoff JL, Jaso-Friedmann L, and Evans DL. J Appl Physiol 78: 1547-1554, 1995) that activity wheel running abolished the suppression of footshock-induced natural killer (NK) cell cytolysis. Twenty-four male Fischer 344 rats were assigned to one of three groups (n = 8, all groups): 1) a home-cage control group, 2) a sedentary treatment group, or 3) a treadmill-running group (0 degrees incline, 25 m/min, 35 min/day, 6 days/wk). After 6 wk, the treadmill and sedentary groups received 2 days of footshock. Splenic NK cytotoxicity was determined by standard 4-h (51)Cr release assay. Percentages of lymphocytes were determined by flow cytometry. Plasma levels of ACTH, corticosterone, and prolactin concentration were measured by radioimmunoassay. After footshock, percentage of lysis relative to home-cage controls was 40% and 80% for sedentary and treadmill-trained animals, respectively (P < 0.05). Our results indicate that the protective effect of chronic exercise on innate cellular immunity in the Fischer 344 male rat is not restricted to activity wheel running, nor is it explained by elevations in basal NK activity, increased percentages of splenic NK and cytotoxic T cells, or increased plasma levels of ACTH, corticosterone, and prolactin.
The evolution of advanced laparoscopic techniques requires animal models for instrument development, evaluation of the physiopathological correlation and physician training. Selection of surgical models is primarily based on cost, availability, anatomic and physiologic considerations, and housing and anesthetic methods. The use of large animals is becoming increasingly difficult due to restrictive legislation, public concern, and economic factors. A standardized technique of laparoscopic surgery in the rat has been developed to perform procedures in all abdominal regions including fundoplication, splenectomy, nephrectomy, liver resection, herniorraphy, colotomy, colectomy, and retroperitoneal exploration. The equipment consists of a specially designed small animal operating table, a standard arthroscope and micro-instruments. The rat model gives the opportunity to investigate the physiopathological relations and immune functions of laparoscopic procedures, to develop micro-instruments under realistic conditions of a live organism, and it is an excellent training model especially for pediatric and microsurgery. Besides low costs and easy availability, the rat model requires less logistic and financial efforts.
The Western Pacific Regional Committee of the World Health Organization (WHO) resolved in 1988 to eradicate poliomyelitis in the region by 1995. Despite intensified surveillance for acute flaccid paralysis (AFP), reported cases of poliomyelitis decreased from 5485 in 1989 to 1909 in 1992. Of the five countries in the region that continue to report endemic poliomyelitis (Cambodia, People's Republic of China Laos, Republic of the Philippines, and Vietnam), reported incidence is lowest in Philippines, which also was the first country in the region to undertake national immunization days (NIDs) with oral poliovirus vaccine (OPV); in addition, other vaccines were administered at vaccination posts by trained health workers. This report assesses the impact of Philippines' first NID, which was initiated as part of its poliomyelitis eradication efforts, and summarizes progress toward eradication of poliomyelitis in Philippines.