Chaos control of cardiac arrhythmias

Chaos theory has shown that many disordered and erratic phenomena are in fact deterministic, and can be understood causally and controlled. The prospect that cardiac arrhythmias might be instances of deterministic chaos is therefore intriguing. We used a recently developed method of chaos control to stabilize a ouabain-induced arrhythmia in rabbit ventricular tissue in vitro. Extension of these results to clinically significant arrhythmias such as fibrillation will require overcoming the additional obstacles of spatiotemporal complexity.     

Improving blood donor recruitment and retention: integrating theoretical advances from social and behavioral science research agendas

BACKGROUND: Increasing blood donor recruitment and retention is of key importance to transfusion services. Research within the social and behavioral science traditions has adopted separate but complementary approaches to addressing these issues. This article aims to review both of these types of literature, examine theoretical developments, identify commonalities, and offer a means to integrate these within a single intervention approach. STUDY DESIGN AND METHODS: The social and behavioral science literature on blood donor recruitment and retention focusing on theory, interventions, and integration is reviewed. RESULTS: The role of emotional regulation (anticipated anxiety and vasovagal reactions) is central to both the behavioral and the social science approaches to enhancing donor motivation, yet although intentions are the best predictor of donor behavior, interventions targeting enactment of intentions have not been used to increase donation. Implementation intentions (that is, if-then plans formed in advance of acting) provide a useful technique to integrate findings from social and behavioral sciences to increase donor recruitment and retention. CONCLUSION: After reviewing the literature, implementation intention formation is proposed as a technique to integrate the key findings and theories from the behavioral and social science literature on blood donor recruitment and retention.     

Age differences in the consistency of cardiovascular response patterns in healthy women

To determine if response consistency is higher in older women, twenty young adult (mean = 20 years) and twenty-two elderly (mean = 82 years) women participated in a 20-min stress protocol including serial subtraction, anxiety and anger imagery tasks. All subjects were healthy and free of diagnosed cardiovascular disease. Heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) responses to the tasks were assessed. To allow comparisons of the effects of stress on different cardiovascular parameters, all baseline-stress change scores were converted to z-scores. Forty-two 3(parameter)X3(stressor) matrices of z-scores, one for each subject, were created. Intraclass correlations computed using these matrices revealed greater consistency of response hierarchies (e.g., DBP greater than SBP greater than HR) among elderly subjects. Possible mechanisms for this effect are discussed.     

Sialyltransferase ST3Gal-IV operates as a dominant modifier of hemostasis by concealing asialoglycoprotein receptor ligands

A number of poorly characterized genetic modifiers contribute to the extensive variability of von Willebrand disease, the most prevalent bleeding disorder in humans. We find that a genetic lesion inactivating the murine ST3Gal-IV sialyltransferase causes a bleeding disorder associated with an autosomal dominant reduction in plasma von Willebrand factor (VWF) and an autosomal recessive thrombocytopenia. Although both ST3Gal-IV and ST6Gal-I sialyltransferases mask galactose linkages implicated as asialoglycoprotein receptor ligands, only ST3Gal-IV deficiency promotes asialoglycoprotein clearance mechanisms with a reduction in plasma levels of VWF and platelets. Exposed galactose on VWF was also found in a subpopulation of humans with abnormally low VWF levels. Oligosaccharide branch-specific sialylation by the ST3Gal-IV sialyltransferase is required to sustain the physiologic half-life of murine hemostatic components and may be an important modifier of plasma VWF level in humans.     

Cytoreduction combined with intraperitoneal hyperthermic perfusion chemotherapy in advanced/recurrent ovarian cancer patients: The experience of National Cancer Institute of Milan.

AIMS: We report the effects of cytoreductive surgery (CRS) and intraperitoneal hyperthermic perfusion (IPHP) in the treatment of advanced/recurrent epithelial ovarian cancer (EOC) on survival, morbidity and mortality. PATIENTS: Forty EOC patients were studied. Median age was 52.5 years (range: 30-68) and median follow-up 26.1 months (range: 0.3-117.6). Most patients presented advanced disease (stage III/IV). Previous systemic chemotherapy included cisplatin-based, taxol-based or taxol/platinum containing regimens. RESULTS: After the CRS, 33 patients presented no macroscopic residual disease. Five-year overall survival was 15%; the mean overall and progression-free survivals were 41.4 and 23.9 months, respectively. The morbidity, toxicity and mortality rates were 5%, 15% and 0%, respectively. CONCLUSION: Our results suggest that CRS + IPHP merits further evaluation by a formal prospective trial.     

Advance directives as acts of communication: a randomized controlled trial

BACKGROUND: Instructional advance directives are widely advocated as a means of preserving patient self-determination at the end of life based on the assumption that they improve surrogates' understanding of patients' life-sustaining treatment wishes. However, no research has examined whether instructional directives are effective in improving the accuracy of surrogate decisions. PARTICIPANTS AND METHODS: A total of 401 outpatients aged 65 years or older and their self-designated surrogate decision makers (62% spouses, 29% children) were randomized to 1 of 5 experimental conditions. In the control condition, surrogates predicted patients' preferences for 4 life-sustaining medical treatments in 9 illness scenarios without the benefit of a patient-completed advance directive. Accuracy in this condition was compared with that in 4 intervention conditions in which surrogates made predictions after reviewing either a scenario-based or a value-based directive completed by the patient and either discussing or not discussing the contents of the directive with the patient. Perceived benefits of advance directive completion were also measured. RESULTS: None of the interventions produced significant improvements in the accuracy of surrogate substituted judgment in any illness scenario or for any medical treatment. Discussion interventions improved perceived surrogate understanding and comfort for patient-surrogate pairs in which the patient had not completed an advance directive prior to study participation. CONCLUSIONS: Our results challenge current policy and law advocating instructional advance directives as a means of honoring specific patient wishes at the end of life. Future research should explore other methods of improving surrogate decision making and consider the value of other outcomes in evaluating the effectiveness of advance care planning.