[The fixed denture care of the periodontally reduced dentition].
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Biomedical subjects
Publications and source records attributed to D König.
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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.
Epidemiologic studies have shown that a dyslipoproteinemia with low concentrations of high density lipoprotein (HDL) cholesterol and elevated serum triglycerides (TG) is associated with a particularly high incidence of coronary artery disease. This lipid profile is associated with increased concentrations of small, dense low density lipoprotein (LDL) particles. To evaluate the role of mild to moderately elevated TG on the LDL subfraction profile in patients with low HDL cholesterol, concentration and composition of six LDL subfractions was determined by density gradient ultracentrifugation in 41 healthy men (31+/-9 years, body mass index (BMI) 25.1+/-3.9 kg/m2) with equally low HDL cholesterol levels < 0.91 mmol/l but different TG levels: TG < 1.13 mmol/l, n = 16; TG = 1.13-2.26 mmol/l, n = 13: TG = 2.26-3.39 mmol/l, n = 12. Those men with moderately elevated TG levels between 2.26 and 3.39 mmol/l had significantly higher concentrations of very low density lipoprotein (VLDL), intermediate low density lipoprotein (IDL), and small, dense LDL apoB and cholesterol than men with TG < 1.13 mmol/l. With increasing serum TG, the TG content per particle also increased in VLDL, IDL as well as total LDL particles while the cholesterol and phospholipid (PL) content decreased in VLDL and IDL, but not in LDL particles. LDL subfraction analysis revealed that only large, more buoyant LDL particles (d < 1.044 g/ml) but not the smaller, more dense LDL, were enriched in TG. Small, dense LDL particles were depleted of free cholesterol (FC) and PL. This study has shown that in men with low HDL cholesterol levels mild to moderately elevated serum TG strongly suggest the presence of other metabolic cardiovascular risk factors and in particular of a more atherogenic LDL subfraction profile of increased concentration of small, dense LDL particles that are depleted in surface lipids.
Insulin resistance is associated with dyslipoproteinemia characterized by increased serum triglycerides, reduced high-density lipoprotein 2 (HDL2) cholesterol, and increased small, dense low-density lipoprotein (LDL) subfraction particles. Physical activity and weight reduction are known to improve insulin resistance and dyslipoproteinemia, but their influence on LDL subfractions in diabetic patients is unknown. Therefore, we investigated the effect of a 4-week intervention program of exercise (2,200 kcal/wk) and diet (1,000 kcal/d: 50% carbohydrate, 25% protein, and 25% fat; polyunsaturated/saturated fat ratio, 1.0) on glycemic control and HDL and LDL subfractions in 34 obese patients with non-insulin-dependent diabetes (age, 49 +/- 9 years; body mass index [BMI], 33.1 +/- 5.1 kg/m2). Reductions in body weight (P < .001) and improvements in fasting blood glucose, insulin, fructosamine (P < .001), and free fatty acids (P < .01) by intervention were associated with reductions in serum cholesterol and apolipoprotein B (apo B) concentrations in very-low-density lipoprotein (VLDL) (P < .01), intermediate-density lipoprotein (IDL), and small, dense (>1.040 g/mL) LDL particles (P < .001). These data underlie the positive influence of weight reduction induced by exercise and diet on insulin resistance and lipoprotein metabolism in obese diabetic patients, particularly showing improvements of the LDL subfraction profile with a decrease of small, dense LDL particles. This is of particular importance, as these particles have been shown to be associated with coronary artery disease.
Biofilms occur in natural aquatic ecosystems and on surfaces of biomaterials. They are generally associated with clinical infections predominantly of prosthetic hip joints, heart valves and catheters. Sessile microorganisms may be intimately associated with each other and to solid substratum through binding to and inclusion into exopolymer matrices on biofilms. The establishment of functional colonies within the exopolymeric matrices generate physico-chemical gradients within biofilms, that modify the metabolism and cell-wall properties of the microorganism. A consequence of biofilm growth is an enhanced microbial resistance to chemical antimicrobial agents and antibiotics. Investigations on the antimicrobial efficacy of antibiotics, antiseptics and antimicrobial heavy ions, however, gave controversial results. No single antimicrobial substance has been developed for the efficient eradication of adherent bacteria. This review elucidates the mechanisms of microbial resistance in biofilms and strategies for the prevention of biofilm development. Pharmacokinetical and pharmacodynamical issues for the screening of biofilm-active drugs are presented. Combinations of antistaphylococcal antibiotics with rifampin may be advantageous for preventing and curing biomaterial infections.
The aim of the present study was to investigate the influence of a yeast cell preparation rich in antioxidant vitamins, antioxidant enzymes, trace elements and minerals on the exercise-induced stress reaction and antioxidant status. The study was carried out in a non-blinded, controlled design. After a 6 week pre-ingestion period, 9 highly endurance-trained athletes took the preparation twice daily for another 6 weeks. After each phase venous blood samples were drawn in the resting state after an overnight fast followed by a strenuous 15 km cross country race. 1 h after the exercise venous blood sampling was repeated. Compared to the pre-ingestion period, the following significant alterations could be detected after 6 weeks of ingestion: 1) In the resting state, soluble interleukin-2 receptor (p < 0.05) and plasma fibrinogen (p < 0.01) were shown to be lower whereas plasma fibronectin was increased (p < 0.01). 2) 1 h after the race the significant difference in fibrinogen and fibronectin was confirmed. In addition myoglobin (p < 0.01) and CKMM3 (p < 0.05) as well as mangan superoxid dismutase (p < 0.05) were reduced. In conclusion, the 6-week ingestion-period resulted in an improvement of the systemic and muscular stress reaction. In addition, the decrease in mangan superoxide dismutase concentration can be interpreted as a sign of reduced free radical stress. However, these preliminary results have to be confirmed in larger trials in blinded designs. In addition, there seems to be a rationale for testing the effects of yeast-cell preparations in patients with chronic degenerative diseases as some of the investigated parameters are involved in the pathophysiology of such illnesses.
Spinal cord lesion leads to an interruption of pathways from brain to the peripheral sympathetic nervous system, which results in pathological changes in sympathetic innervation. Free epinephrine (E), norepinephrine (NE) and dopamine (DA) were measured in 30 tetraplegics (TETRA), 15 high-lesion paraplegics (T1 and T4, HPARA), 15 paraplegics with injuries between T5 and T10 (MPARA), 15 low-lesion paraplegics (below T10, LPARA) and 16 non-handicapped control persons (C) at rest, at 60 and 100% of maximal oxygen consumption during graded wheelchair ergometry (WCE). The TETRA showed significant lower E and NE levels at rest and only slight increases during physical exercise. The E and NE concentrations of the paraplegics with a lesion below T5 were significantly higher than those of the high-lesion paraplegics, as well as those of the control persons at every point in the study. All paraplegics and the control persons showed, at submaximal and maximal exercise, a significant increase in NE. Only a slight increase in E in HAPRA was shown. No differences were found at rest and during exercise in E and NE levels in the MPARA and LPARA. No significant differences were found in the dopamine concentration at rest or during exercise for any of the groups. In summary, different levels of lesion and the resulting interruption to sympathetic pathways in the spinal cord are decisive factors in the degree of impairment of sympathetic innervation in SCI persons. Tetraplegics show less preganglionic resting activity because of interruption of impulses from central centers and no considerable stimulation of the sympathetic nervous system during maximal exercise. Individuals with high paraplegia have a partial impairment of catecholamine release, especially of epinephrine, at rest and during exercise. Paraplegics with a lesion level below T5 showed an augmented basal and exercise-induced upper spinal thoracic sympathetic activity in comparison to control persons.
BACKGROUND: Patients with chronic heart failure show impairment of ventilatory efficiency, defined as the relation between ventilation and carbon dioxide output. It is caused by ventilation of excess physiologic dead space. We hypothesized a role of active vasoconstriction in the increase of physiologic dead space, presumed to lead to alveolar hypoperfusion. METHODS AND RESULTS: In 57 patients with chronic heart failure (New York Heart Association classification II through IV, ejection fraction 25.6%+/-10.4%) and 7 control subjects, gas exchange at rest and on exercise was compared with hemodynamic measurements and, in a subgroup of 15 patients, with endothelin-1, epinephrine, and norepinephrine levels in the pulmonary and systemic circulation. Ventilatory efficiency at rest (VE/VCO2 ratio) correlated with ventilatory efficiency on exercise (VE vs VCO2 slope). Impairment of ventilatory efficiency correlated strongly negative with exercise tolerance (maximal oxygen uptake: r = -0.67) and cardiac output (r = -0.66) and positive with pulmonary hypertension (mean pulmonary artery pressure: r = 0.69, pulmonary vascular resistance: r = 0.60). None of the vasoconstrictors correlated with reduction of ventilatory efficiency in the subgroup studied. CONCLUSIONS: Impairment of ventilatory efficiency in chronic heart failure is correlated with resting pulmonary artery pressures and associated with the impairment of exercise capacity. An imbalance of pulmonary vascular tone probably leads to both pulmonary hypertension and alveolar hypoperfusion.
The purpose of this study was to investigate the influence of different injury levels in persons with spinal cord injury (SCI) on epinephrine (Epi) and norepinephrine (NE) at rest and during graded wheelchair exercise and the related changes in heart rate and O2 uptake (VO2). Twenty tetraplegics (Tetra), 10 high-lesion paraplegics (HLPara), 20 paraplegics with SCI below T5 (MLPara), and 18 able-bodied, nonhandicapped persons (AB) were examined. Because of the higher level of interruption of the sympathetic pathways, Tetra persons showed lower Epi and NE at rest and only slight increases during exercise compared with all other groups; the Tetra subjects' impaired cardiac sympathetic innervation caused restricted cardioacceleration and strongly reduced maximal VO2. When compared with AB persons, HLPara had comparable NE but lower Epi levels as a result of partial innervation of the noradrenergic system and denervation of the adrenal medulla. MLPara subjects showed an augmented basal and exercise-induced upper spinal thoracic sympathetic activity compared with AB subjects. The increase in heart rate in relation to VO2 was higher in HLPara because of a smaller stroke volume as a result of venous blood pooling. The different exercise response in persons with SCI is a result of the interruption of pathways in the spinal cord to the peripheral sympathetic nervous system in addition to the motor paralysis.
Intense physical exercise has been shown to be associated with immunosuppression and increased rate of infection. The immunosuppressive effect of exhaustive exercise has been attributed to a reduced helper/suppressor T-cell ratio, low salivary levels of immunoglobulin-A, decreased lymphocyte proliferative response and natural killer cell activity, and elevation of stress hormones. Yet some athletes can withstand intense training periods without health problems while others are prone to infections. Thus it has been postulated that other factors may interfere with immunoregulation. The notion that macro- and micronutrients are involved in the regulation of immunological processes and the ability to cope with muscular and systemic exercise stress has been gaining attention. Particularly trace elements have been shown to be related to cell mediated and humoral immunity such as NK-cell activity, T- and B-cell functions, and cytokine release. Many investigations have reported decreased concentrations of trace elements in blood and tissues after training and competition. However, the magnitude of losses is highly dependent on the type and intensity of exercise, the individual regulatory state, and most important, nutrition. This paper reviews the data on zinc, iron, and magnesium status in athletes and summarizes the consequences of deficiencies in these trace elements regarding exercise tolerance and immune function. These elements were chosen since there is evidence they are related to exercise-induced stress and immune function.
Elevated serum ferritin concentrations between 200 and 500 microg/l have been found to be a strong risk factor for acute myocardial infarction in Finnish men, but the reason for this association is still uncertain. In the Finnish population ferritin concentrations correlated with factors of insulin resistance syndrome. As these factors have been found to be associated with an LDL subfraction phenotype of increased concentrations of small, dense LDL particles, we hypothesized an association between ferritin and an atherogenic LDL subfraction profile, a finding which could be an explanation for the observed relationship between ferritin and atherosclerosis. Therefore we determined serum ferritin levels, metabolic cardiovascular risk factors, and the LDL subfraction phenotype in 93 healthy men without signs for infection or coronary heart disease. We found that men with moderately elevated ferritin levels (200-500 microg/l; n = 31) had a significantly worse coronary risk profile than men with lower levels ( < 200 microg/l; n = 62). Elevated ferritin concentrations were associated with significantly higher values for serum triglycerides, VLDL cholesterol, VLDL apolipoprotein B (P < 0.01), IDL cholesterol, fasting glucose (P < 0.05) and uric acid (P < 0.01), and lower levels for HDL2b and HDL2a cholesterol and apolipoprotein A-I (P < 0.05), and lipoprotein(a) (P < 0.01). Elevated ferritin levels were, however, not associated with an unfavourable LDL subfraction profile of increased concentrations of small, dense LDL particles.
The relation between nutrition and sport has been studied extensively during recent decades. Nevertheless, research interest was focused mainly on the role of dietary macro- and micronutrients as ergogenic aids. Today, there is increasing support for the hypothesis that the nutrient status also has relevance for the prevention and rehabilitation of systemic and muscular stress induced by intense physical exercise. The increase in muscular stress is indicated by the rise in creatine kinase and myoglobin; the systemic stress is associated with characteristic immunological and hormonal changes and an acute-phase response. During and following exercise, the course of cytokines (especially interleukin 6) and acute-phase proteins (C-reactive protein, fibrinogen) as well as cortisol levels are an indirect measure of the exercise intensity and the individual ability to cope with physical stress. It has been shown that the dietary intake and, consequently, the systemic or intracellular concentrations of minerals such as magnesium and zinc, vitamins with antioxidant capacity (vitamin E, C, E, and beta carotine), and the composition of fatty acids can be related to the exercise-induced stress response. Therefore, this review deals specifically with the impact of these nutritional components on the reduction of sports specific muscular damage and systemic stress, especially under the aspect of increased losses during and following intense physical exercise.
There is evidence that a low-density lipoprotein (LDL) subfraction profile of increased concentrations of small, dense LDL particles is less common among trained than among sedentary normocholesterolemic men, but it is still uncertain whether there is a similar association in hypercholesterolemia also. Therefore, we determined the lipid and apolipoprotein concentration and composition of six LDL subfractions (density gradient ultracentrifugation) in 20 physically fit, regularly exercising (>three times per week) hypercholesterolemic men and 20 sedentary hypercholesterolemic controls. Trained (maximal oxygen consumption [VO2max], 57.3 +/- 7.4 mL/kg/min) and sedentary (VO2max, 37.5 +/- 8.8 mL/kg/min) individuals (aged 35 +/- 11 years; body mass index [BMI], 23.9 +/- 2.7 kg/m2) were matched for LDL apolipoprotein (apo) B levels (108 +/- 23 and 112 +/- 36 mg/dL, respectively). Trained subjects had significantly lower serum triglyceride (P < .05) and very-low-density lipoprotein (VLDL) cholesterol levels (P < .05) and higher high-density lipoprotein 2 (HDL2) cholesterol levels (P < .01) than sedentary controls. LDL particle distribution showed that trained individuals had significantly less small, dense LDL (d = 1.040 to 1.063 g/mL) and more large LDL (d = 1.019 to 1.037 g/mL) subfraction particles than sedentary controls, despite equal total LDL particle number. Analysis of LDL composition showed that LDL particles of hypercholesterolemic trained men had a higher free cholesterol content than LDL of untrained hypercholesterolemic men. Small, dense LDL in hypercholesterolemic trained men were richer in phospholipids than those in sedentary controls. These data demonstrate the significant influence of aerobic fitness on lipoprotein subfraction concentration and composition, thereby emphasizing the role of exercise in the treatment and risk reduction of hypercholesterolemia.
Fifteen athletes were investigated 24 h before, 1 h after, and 20 h after an exhaustive exercise stress test (mean duration 68 min). Testing for cytokines was done in serum, urine, and the supernatants of whole blood cell cultures, which were stimulated with lipopolysaccharide (LPS), concanavalin A (Con A), or phythaemagglutinin (PHA). Elevated levels of interleukin 6 (IL-6) and soluble IL-2 receptor (sIL-2R) were found 1 h after the run in both serum and urine samples. TNF-alpha in serum was also increased, whereas IL-2 in urine was decreased after the exercise. All other testings in serum and urine (including IFN-gamma) gave borderline or negative results. In cell cultures, the LPS-induced release of the inflammatory cytokines TNF-alpha, IL-1, and IL-6 was suppressed 1 h after exercise. Also, the Con-A-induced and LPS-induced release of IFN-gamma, and the PHA-induced release of IL-2 were suppressed 1 h after exercise. In contrast, Con-A-induced release of IL-2 was mildly increased after the run. We conclude that exercise of the intensity and duration described here causes an activation of the immune system, which is immediately counter-regulated. Twenty hours after the exercise, most of the observed changes were back to pre-exercise levels, indicating only a short duration for this suppressive counter-regulation.
OBJECTIVE: Based on the study of existing simulation and mathematical models, a dynamic simulation and three-dimensional (3-D) visualization model of the normal and pathologic architecture of the nasal epithelium is proposed. STUDY DESIGN: Positions, sizes, shapes and orientations of the nuclei, basal lamina and lumen were used for 3-D representation of the epithelium. Static modeling was applied to simulate the normal, metaplastic and dysplastic stages of the nasal epithelium. Then, dynamic modeling, starting from a static representation of a normal or a pathologic stage, used the starting values of cell proliferation parameters to simulate a tissue growth process. The basic hypothesis is that consecutive transformations through stages are mainly due to increased cell growth. RESULTS: Normal tissue renewal and progressive transitions between normality and hyperplasia after exposure to formaldehyde were obtained. CONCLUSION: A model that allows study of the evolution of the 3-D tissue architecture during the preneoplastic process in external epithelium is now available. Improvement of the model, consisting of adding information concerning cell communication, extracellular matrix and cell cycle modeling, should help to formulate and sharpen hypotheses concerning structural and kinetic dynamics of this tissue during the preneoplastic process.
The immunologic response to exercise comprises numerous alterations within the immune system, but how these processes are regulated is still largely unknown. Exercise-related immunological changes include signs of inflammation, such as release of inflammatory mediators, activation of various white blood cell lines and complement, and induction of acute phase proteins. Nevertheless, signs of immunosuppression, such as decreased T and B cell function or impaired cytotoxic or phagocytic activity, can also be observed. Some data suggest that essential fatty acids help regulate inflammatory processes, modulating both cytokine release and the acute phase response. Positive effects of changing dietary essential fatty acids have been demonstrated in chronic inflammatory diseases. In contrast, little is known about the contribution of fatty acids to the exercise-induced immunologic reaction. Essential fatty acids may determine alterations within the immune system following exercise. Therefore, future studies are necessary to evaluate the influence of the fatty acid composition on the inflammatory or immunosuppressive component following heavy exertion.
During recent years the echocardiographic procedure has been extended regarding the evaluation of left ventricular myocardial function during exertion. During exercise echocardiography, body position is important for the correct assessment of cardiac dimensions and function, particularly for the measurement of the cross-sectional diameters of the left ventricle and diastolic myocardial function. Reliable parameters of left ventricular function during exercise are left ventricular ejection fraction and endsystolic left ventricular volume, but not enddiastolic left ventricular volume. The increase of left ventricular ejection fraction during exercise up to submaximal exertion primarily results in a reduction of endsystolic left ventricular volume and partially in a simultaneous increase of enddiastolic left ventricular volume. In several cross-sectional studies comparing untrained and endurance trained hearts a higher diastolic filling rate, a higher maximal blood flow velocity of early diastolic passive left ventricular filling and a higher early diastolic filling fraction at rest and during exercise could be proved in endurance trained hearts. These training-induced adaptations of diastolic left ventricular function have been confirmed by a longitudinal study with primarily untrained young and older healthy subjects performing a heart rate controlled endurance training programme. Stress echocardiographic and simultaneous spiroergometric investigations indicated a correlation between the diastolic left ventricular function and the maximal oxygen uptake. The currently available data on the sensitivity, the intraobserver and interobserver variability of Doppler echocardiography have shown that this non-invasive procedure is valid for the evaluation of the systolic and the diastolic myocardial function at rest and during exercise. However, the procedure is limited to patients where the ultrasonographic assessment of cardiac structures is not considerably restricted. Furthermore, the reliability of stress Doppler echocardiography is dependent considerably on the practical skills of the observer.
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