Coupling of local muscle deoxygenation and autonomic control depends on exercise intensity-insights from transfer entropy analysis.

OBJECTIVE: We analyzed the driving component between the periods of adjacent heartbeats (R-R intervals) and vastus lateralis-deoxygenation (%HHb) during incremental cycling. Considering a tight matching of local metabolism with systemic and local perfusion, a coupling between indices of cardiovascular control (R-R variability) and %HHb is suggested. Further, an intensity-dependent coupling between R-R variability and %HHb was hypothesized, because a multitude of feedback and feedforward mechanisms to autonomic cardiovascular control as well as local vasodilating mechanisms are associated with muscle metabolism and thus exercise intensity. APPROACH: Ten male triathletes (age: 34 ± 8 years) completed a test, including baseline (BAS, 50 W), a 25 W * min-1 ramp incremental phase until exhaustion and a recovery period (REC, 50 W). R-R intervals, %HHb and respiratory responses were simultaneously recorded. Five corresponding data segments were selected: BAS, before the first ventilatory threshold (preGET), between GET and the respiratory compensation point (preRCP), above RCP (postRCP), and REC. Bivariate transfer entropy (BTE) was applied to determine the signal coupling between R-R and %HHb. MAIN RESULTS: During preGET and preRCP, the analysis yielded the dominating direction from %HHb to R-R intervals, while for postRCP the direction was reversed. No significant signal coupling was detectable for the BAS and REC segments. SIGNIFICANCE: Assuming that %HHb is related to the metabolic state of the working muscle, BTE results support the role of metaboreceptors in the systemic blood flow regulation at lower exercise intensities, while other mechanisms (e.g. baroreceptor and mechanoreceptor feedback, central command) that modulate cardiovascular control may override this coupling at higher intensities.

[Individualization of exercise load control for inpatient cardiac rehabilitation. Development and evaluation of a HRV-based intervention program for patients with ischemic heart failure]. / Individualisierung der Belastungssteuerung in der kardiologischen stationären Rehabilitation. Entwicklung und Evaluation eines HRV-gesteuerten Interventionsprogramms für Patienten mit ischämisch bedingter Herzinsuffizienz.

BACKGROUND: The effective use of rehabilitation programs is of primary importance in order to improve the physical performance of cardiac disease patients. A modular program has been developed which is intended to structure and individualize conventional, exercise-based rehabilitation programs according to the individual needs and physical condition of each patient. The individualization of the program is based on detailed diagnostics before patients enter the program and daily measurements of heart rate variability (HRV) during cardiac rehabilitation. METHODS: A total of 30 patients with ischemic heart disease were randomly assigned either to the intervention group (IG), completing the modular individualized rehabilitation program [n=15, mean age 54.4±4.2 years and mean left ventricular ejection fraction (LVEF) 28.53±6.25%) or to the control group (CG) taking part in the conventional rehabilitation program (n=15, mean age 56.4±4.4 years and mean LVEF 27.63±5.62). Before and after the intervention, cardiorespiratory fitness was assessed by measurement of maximal oxygen consumption (relative VO2max) during bicycle ergometry and the 6-minute walk test (6-MWT). Pre-post comparisons of cardiorespiratory fitness indicators were used to evaluate the effectiveness of the rehabilitation program. In addition to the results of the basic clinical investigations and the cardiorespiratory testing, results of standardized HRV measurements of 10 min at morning rest served as criteria for program individualization. RESULTS: The relative VO2max increased significantly (p<0.05) in the IG whereas no change was found in the CG. Similar results were found for maximum power output during bicycle ergometry (p<0.01) and for 6-MWT distance (p<0.001). Although patients in the IG completed less aerobic exercise sessions than those in the CG (p<0.001) the physical performance of the IG improved significantly. DISCUSSION: The results prove the effectiveness and efficacy of the modular individualized rehabilitation program. They further suggest the need for an individual program matrix instead of a maximum performance matrix in cardiac rehabilitation. Individualization should be based on clinical and performance diagnostics before and accompanying assessments of training condition, e.g. by HRV measurements, during rehabilitation programs. Each patient should only perform those intervention programs which match the results of the basic clinical investigation and additional analyses during rehabilitation.

[Work-Related Setting Approach with Health Counselling Supports a Healthy Lifestyle of Long-Term Unemployed Persons]. / Arbeitsmarktintegratives Setting mit Gesundheitsberatung unterstützt gesundheitsförderlichen Lebensstil bei Langzeiterwerbslosen.

Unemployment is a major reason for health inequalties. In a pilot study (N=119), the acceptance and effectiveness of a low threshold health promotion intervention for older long-term unemployed persons were evaluated. Health counselling supported the participants in the development of a healthy lifestyle.

Arginine inhibits hemostasis activation.

BACKGROUND: The diagnosis and the therapy of in vivo hemostasis activation is of great clinical importance. Artefactual changes of the hemostasis (i.e., coagulation or fibrinolysis) in vitro have to be prevented. Usual in vitro anticoagulation by sodium citrate does not fully inhibit coagulation--or fibrinolysis--activation. Therefore, there is need for a simple physiologic inhibitor of hemostasis activation both in diagnosis and therapy of hemostasis activation. METHODS: Whole blood clotting time (WBCT), prothrombin time (PT), activated partial thromboplastin time (APTT), in vitro bleeding test closure time (IVBT-CT), and whole blood aggregometry (WBA) were determined in normal human blood or plasma, supplemented with increasing concentrations of L-arginine or guanidine. RESULTS: Arginine in concentrations of 5-100 mM inhibited the WBCT, PT, APTT, IVBT-CT, and WBA. Arginine (50 mM) resulted in a two-fold prolongation of WBCT, PT, or IVBT-CT (the anti-epinephrine action is superior to the anti-ADP action), a four-fold prolongation of APTT or a 60% inhibition of WBA. CONCLUSION: L-Arginine (or guanidine) inhibited the activation of hemostasis. Arginine might be used as hemostasis stabilizer both in the diagnosis and therapy of hemostasis activation. The usage of arginine as an in vitro hemostasis inhibitor might be indicated in the diagnosis of hemostasis activation, as occurring in pharmacological thrombolysis or disseminated intravascular coagulation (DIC). The storage of blood or blood products might be improved by arginine stabilization. The amino acid (and nitric oxide precursor) L-arginine could be an interesting new pharmacologic agent to inhibit a pathologic hemostasis activation.

[Preoperative donation of autologous blood and plasma]. / Die präoperative autologe Blut- und Plasmaspende.

The risk and side effects of homologous blood transfusion led to an increased interest in autologous transfusion concepts. Whereas peri- and intraoperative procedures are clinical methods, preoperative autologous blood donation belongs into the responsibility of a transfusion service in order to ensure qualified separation into blood components as well as correct storage and handling. Special knowledge in transfusion medicine is necessary for the application of preoperative autologous plasmapheresis. On the other hand, its use by clinicians under adequate controlled conditions seems to be rather safe. Although autologous transfusion includes the lowest risk, side reactions cannot be completely excluded. There is also a risk of secondary bacterial contamination. Side effects due to the specific composition of the various blood components, to alterations during storage and to the way of application have to be considered, too. Severe haemolytic transfusion reactions are mostly caused by exchange of blood samples, patients or blood units. They are to be expected in autologous blood transfusion as well. In addition, there is an increased risk of infection when autologous blood components are exchanged accidentally. There is only an indication for autologous blood if the total risk of autologous donation as well as transfusion in the individual case is lower than the statistical risk of homologous transfusion. Autologous blood donation should be offered to all patients undergoing elective surgery where blood is likely to be required and when blood donation is practicable. Preoperative autologous plasmapheresis is indicated in elective surgery if intra- and perioperative autotransfusion methods shall be used and a blood loss of at least 1.5 liters can be expected. There are a lot of organizational problems in autologous blood transfusion which can be solved by adequate information of all persons involved and close cooperation between clinicians and transfusion service. The high standard which was developed for homologous transfusion in the last 15 years has to be maintained for autologous blood transfusion, too.

[New aspects of blood component therapy]. / Neue Aspekte der Blutkomponententherapie.

The medical demand for factor VIII is increasing through continuously improved therapy of patients suffering from haemophilia A. The most important raw material for the production of factor VIII is fresh frozen plasma (FFP). Its clinical usage increased in the last few years dramatically. An alternative to FFP is the high grade blood component cryo-poor plasma (CPP). CPP is characterized by a deficiency of factor VIII and fibrinogen which is not of clinical relevance. It can be used instead of FFP in 95% of cases. Thus, FFP is more available for the production of factor VIII and the supply of factor VIII for haemophiliacs will improve.

[Inhibitor hemophilia A--diagnostic and therapeutic significance of controlled substitutions with factor VIII]. / Hemmkörperhämophilie A--Diagnostische und therapeutische Bedeutung kontrollierter Substitutionen mit Faktor VIII.

10 haemophiliacs with constant low inhibitor levels to factor VIII (0.5-2.5 Bethesda units (BU) per ml) and 4 patients without antibodies were examined by a controlled substitution with factor VIII. We investigated the factor VIII in-vivo-recovery, the half disappearance time and the biological half-life. 4 different reaction patterns could be observed: 6 patients with antibodies showed the same recovery as those haemophiliacs without inhibitors but the half life was shorter. 2 inhibitor patients did not achieve the expected increments of factor VIII, but had normal half life. One patient had reduced recovery and shortened half life. Only in one patient (inhibitor levels 0.8-1.0 BU/ml) all parameters were in the normal range.

[Quality parameters of cryoprecipitates from stored blood preservation]. / Qualitätsparameter von Kryopräzipitaten aus gelagerten Blutkonserven.

The investigations of a series of 281 cryoprecipitates produced from blood stored at 10 degrees C for 12-18 hours resulted in equal values as compared with those preparations from a control group of 53 preparations which had been prepared from blood maximally stored for 4 hours. Thus, international experiences could be confirmed. An improvement in the quality of erythrocyte concentrates simultaneously produced can be regarded as an additional advantage with respect to the formation of microaggregates during the time the stored blood can be made use of.