Metabolism: flow and contractility of the Langendorff heart

This thesis reviews current literature and describes experimental studies on the regulation and modification of coronary flow and contractility in isolated rat hearts. In chapter I and introduction is given to the problems of fatty acid toxicity and myocardial function. Coronary flow rate and pump function of the myocardium are mainly determined by the contractile status of vascular smooth muscle cells and cardiac striated muscle cells, respectively. Therefore in chapters II and III morphological and (ultra)structural aspects of both types of cells have been described. In chapters IV and V functional and metabolic aspects of coronary circulation and contractility are illustrated. In both vascular smooth and cardiac striated muscle cells: (i) the intracellular calcium concentration is the main determinant of the contractile status of actomyosin, (ii) contraction takes place after the action potentialinduced calcium-influx through the plasmamembrane and calcium release from intracellular stores (sarcoplasmic reticulum, mitochondria), (iii) relaxation is achieved after reduction of the cytoplasmic calcium level by calcium-pump systems in the plasmamembrane, sarcoplasmic reticulum and mitochondria, (iv) calcium-ions trigger the coupling between the contraction-relaxation cycle with energy metabolism since glycogenolysis and lipolysis are both stimulated by calcium

Outcome measures for complex regional pain syndrome type I: an overview in the context of the international classification of impairments, disabilities and handicaps.

PURPOSE: To determine the availability of relevant and objective outcome measures concerning complex regional pain syndrome type I (CRPS I) for rehabilitation medicine. METHOD: Outcome measures were classified according to the International Classification of Impairments, Disabilities and Handicaps. For each outcome measure a description of concept, operationalization into variables and instrument was given. We performed a PUBMED MEDLINE search (1980-1998) using the following keywords: complex regional pain syndrome, reflex sympathetic dystrophy, impairment, disability, handicap, (long-term) outcome and effect/efficacy. RESULTS: Most outcome measures were concentrated on impairments, whereas measures at the level of disabilities and handicaps, the most relevant levels for rehabilitation medicine, were mentioned in very few studies. Objective outcome measures were merely found at the level of impairment. CONCLUSION: The results indicate a need for the development of relevant outcome measures at the level of disabilities and handicaps that can objectively measure treatment efficacy for CRPS I

Tightness Subtleties for Multi-user PKE Notions

Public key encryption schemes are increasingly being studied concretely, with an emphasis on tight bounds even in a multi-user setting. Here, two types of formalization have emerged, one with a single challenge bit and one with multiple challenge bits. Another modelling choice is whether to allow key corruptions or not. How tightly the various notions relate to each other has hitherto not been studied in detail. We show that in the absence of corruptions, single-bit left-or-right indistinguishability is the preferred notion, as it tightly implies the other (corruption-less) notions. However, in the presence of corruptions, this implication no longer holds; we suggest the use of a more general notion that tightly implies both existing options. Furthermore, for completeness we study how the relationship between left-or-right versus real-or-random evolves in the multi-user PKE setting

Analysing the favourable effects of physical exercise:Relationships between physical fitness, fatigue and functioning in Guillain-Barre syndrome and chronic inflammatory demyelinating polyneuropathy

Objective: To elucidate the effects of physical exercise in severely fatigued patients with Guillain-Barr syndrome and chronic inflammatory demyelinating polyneuropathy, and to clarify the mutual relationships between 5 domains studied in these patients: physical fitness, fatigue, objectively measured actual mobility, perceived physical functioning, and perceived mental functioning.Design: Case series.Subjects/patients: Twenty patients with Guillain-Barre syndrome and chronic inflammatory demyelinating polyneuropathy.Methods: The patients undertook a 12-week physical exercise program. Relationships between domains were studied in the change scores, and additionally in the baseline data of patients. The percentage of significant relationships between each pair of domains was determined.Results: In the change scores, a small percentage of significant relationships was found between the physical fitness domain and the other 4 domains (2/30, 7%). A higher percentage of significant relationships was found between the domains perceived mental functioning and actual mobility (44%), perceived mental functioning and perceived physical functioning (44%), and between fatigue and perceived physical functioning (33%). Generally, similar patterns were found in the baseline data.Conclusion: Changes in fatigue, actual mobility and perceived functioning seem not to be influenced by changes in physical fitness. This study stresses the presence and importance of additional effects of a physical training program, not directly related to increasing fitness

Upper limb activity over time in complex regional pain syndrome type 1 as objectively measured with an upper limb-activity monitor: an explorative multiple case study.

BACKGROUND: An upper limb-activity monitor (ULAM) has been developed to determine activity limitations in complex regional pain syndrome type 1 (CRPS1). The ULAM is based on 24h ambulatory monitoring of body segment accelerations and enables valid and objective quantification of mobility and upper limb activity in transversal studies. AIMS: To explore upper limb activity over time in acute upper limb CRPS1 a

Objective measurement of upper limb activity and mobility during everyday behavior using ambulatory accelerometry: the upper limb activity monitor.

Ambulatory accelerometry is a technique that allows objective measurement of aspects of everyday human behavior. The aim of our research has been to develop, validate, and apply this technique, which recently resulted in an upper limb activity monitor (ULAM). The ULAM consists of body-mounted acceleration sensors connected to a waist-worn data recorder and allows valid and objective assessment of activity of both upper limbs during performance of also automatically detected mobility-related activities: lying, sitting, standing, walking, cycling, and general movement. The ULAM can be used to determine (limitations of) upper limb activity and mobility in freely moving subjects with upper limb disorders. This article provides a detailed description of its characteristics, summarizes the results of a feasibility study and four application studies in subjects having upper limb complex regional pain syndrome, discusses the most important practical, technical, and methodological issues that were encountered, and describes current and future research projects related to measuring (limitatio

SoK: Public Key Encryption with Openings

When modelling how public key encryption can enable secure communication, we should acknowledge that secret information, such as private keys or the randomness used for encryption, could become compromised. Intuitively, one would expect unrelated communication to remain secure, yet formalizing this intuition has proven challenging. Several security notions have appeared that aim to capture said scenario, ranging from the multi-user setting with corruptions, via selective opening attacks (SOA), to non-committing encryption (NCE). Remarkably, how the different approaches compare has not yet been systematically explored. We provide a novel framework that maps each approach to an underlying philosophy of confidentiality: indistinguishability versus simulatability based, each with an a priori versus an a posteriori variant, leading to four distinct philosophies. In the absence of corruptions, these notions are largely equivalent; yet, in the presence of corruptions, they fall into a hierarchy of relative strengths, from IND-CPA and IND-CCA at the bottom, via indistinguishability SOA and simulatability SOA, to NCE at the top. We provide a concrete treatment for the four notions, discuss subtleties in their definitions and asymptotic interpretations and identify limitations of each. Furthermore, we re-cast the main implications of the hierarchy in a concrete security framework, summarize and contextualize other known relations, identify open problems, and close a few gaps. We end on a survey of constructions known to achieve the various notions. We identify and name a generic random-oracle construction that has appeared in various guises to prove security in seemingly different contexts. It hails back to Bellare and Rogaway\u27s seminal work on random oracles (CCS\u2793) and, as previously shown, suffices to meet one of the strongest notions of our hierarchy (single-user NCE with bi-openings)

Walking in postpoliomyelitis syndrome: The relationships between time-scored tests, walking in daily life and perceived mobility problems

Objective: To compare walking test results with walking in daily life, and to investigate the relationships between walking tests, walking activity in daily life, and perceived mobility problems in patients with post-poliomyelitis syndrome. Subjects: Twenty-four ambulant patients with post-poliomyelitis syndrome. Methods: Walking tests were performed at self-preferred and maximal speed. Walking activity was measured with an ambulatory activity monitor. Heart rate, step cadence and walking speed in the test and in daily life were compared. Walking speed in daily life was represented by the intensity of walking. Perceived mobility problems were assessed with the Nottingham Health Profile. Results: Heart rate during walking was lower in the test at self-preferred speed than in daily life (mean difference: 11.3 ± 10.4; p = 0.001). Self-preferred walking speed in the test and in daily life correlated significantly (r = 0.55; p = 0.04). In a sub-group with a test performance below the median value, test performance correlated significantly with walking activity. No significant correlation was found between perceived mobility problems and walking activity. Conclusion: Walking in daily life may be more demanding than walking under standardized conditions. Patients with post-poliomyelitis syndrome with the lowest test performance walked less in daily life. Patients do not necessarily match their activity pattern to their perceived mobility problems

The difference between actual and prescribed weight bearing of total hip patients with a trochanteric osteotomy: long-term vertical force measurements inside and outside the hospital

OBJECTIVE: To determine whether patients load the operated leg at a prescribed weight-bearing target load during postoperative recovery. DESIGN: A descriptive prospective study. SETTING: Orthopedic clinic and patients' homes. PARTICIPANTS: Fifty patients who had undergone total hip arthroplasty (THA) with trochanteric osteotomy. INTERVENTION: Patients were verbally instructed by a physical therapist to perform partial weight bearing at a 10% body weight (BW) target load (n=33) or at a 50% BW target load (n=17). MAIN OUTCOME MEASURES: Mean peak load (%BW) and percentage of patients and mean percentage of steps below, equal to, and above the target load. Weight bearing was measured when patients walked with (condition 1) and without (condition 2) a physical therapist in the hospital and walked at home (condition 3). RESULTS: The mean peak load was significantly higher than the target in the 10% BW group for all 3 conditions (condition 1, 19.2% BW; condition 2, 20.0% BW; condition 3, 26.8% BW). In the 50% BW group, the mean peak load was significantly lower than the target in conditions 1 (28.1% BW) and 2 (32.5% BW). No significant difference in weight bearing was found when walking with or without a physical therapist (change in 10% BW, -0.1% BW; change in 50% BW, -3.17% BW). At home, the mean peak load was significantly larger compared with walking without a physical therapist in the hospital (change in 10% BW, -7.0% BW; change in 50% BW, -11.5% BW). CONCLUSIONS: Partial weight bearing at a specific target load was not achieved by patients with a THA when given verbal instructions. Especially when using a low target load and when walking at home with no supervision of a physical therapist, patients loaded the operated leg higher and more frequently above the target load. Other training methods (eg, biofeedback) have to be evaluated to use as training tools for partial weight bearing at specific target loads

Functional capacity and actual daily activity do not contribute to patient satisfaction after total knee arthroplasty

Abstract Background: After total knee arthroplasty (TKA) only 75-89% of patients are satisfied. Because patient satisfaction is a prime goal of all orthopaedic procedures, optimization of patient satisfaction is of major importance. Factors related to patient satisfaction after TKA have been explored, but no studies have included two potentially relevant factors, i.e. the functional capacity of daily activities and actual daily activity. This present prospective study examines whether functional capacity and actual daily activity (in addition to an extensive set of potential factors) contribute to patient satisfaction six months after TKA. Methods: A total of 44 patients were extensively examined preoperatively and six months post surgery. Functional capacity was measured with three capacity tests, focusing on walking, stair climbing, and chair rising. Actual daily activity was measured in the patient's home situation by means of a 48-hour measurement with an Activity Monitor. To establish which factors were related to patient satisfaction six months post surgery, logistic regression analyses were used to calculate odds ratios. Results: Preoperative and postoperative functional capacity and actual daily activity had no relation with patient satisfaction. Preoperatively, only self-reported mental functioning was positively related to patient satisfaction. Postoperatively, based on multivariate analysis, only fulfilled expectations regarding pain and experienced pain six months post surgery were related to patient satisfaction. Conclusions: Functional capacity and actual daily activity do not contribute to patient satisfaction after TKA. Patients with a better preoperative self-reported mental functioning, and patients who experienced less pain and had fulfilled expectations regarding pain postoperatively, were more often satisfied