Assessment of biomaterials as components of a reciprocating dialyser during canine dialysis

A recently reported device, the sorbent suspension reciprocating dialyser (SSRD), was investigated for use as a test system for biocompatibility of dialyser components. The device is easy to assemble and operate, and allows minimal blood contact with foreign material outside of dialyser components. Its constant pressure/ variable flow rate operation allows quantification of degree of clotting of dialyser versus time. The effect of heparinization of the blood distribution gaskets (BDG) of the device on performance and dialyser lifetime was investigated. Heparin was bound to the surface of polyethylene gaskets by immersion in a solution of tridodecylmethylammonium chloride (TDMAC)-heparin complex for several hours. Gaskets were then assembled in an SSRD which was then used for experimental dialysis in dogs with AV shunts. Dialysers assembled using non-heparinized gaskets were used as controls. Blood coagulation tendency was quantified by the activated clotting time (ACT) and partial thromboplastin time (PTT), and these values correlated with the rate of clotting of the device. Heparinization of the gaskets resulted in the prevention of clotting in the dialyser until the final minutes of dialysis in all cases, in contrast to the constant decay of blood fill volume and evidence of clotting in the non-heparinized cases. However, dialyser lifetime was not significantly increased by gasket heparinization. At normal initial values of ACT (80–95 s) dialyser clotting occurred in 10–15 mia In tests with non-heparinized gaskets and systemically heparinized dogs, values obtained in the ACT test were observed to decrease during dialysis, indicating the disappearance of heparin from the blood. Both ACT and PTT tests show promise as predictors of dialyser lifetime.     

Comparison between isoprenaline infusions and bolus injections to assess β-adrenoceptor function in man,with special reference to cardiac contractility and the influence of autonomic reflexes

The present study was performed to characterize cardiovascular responses to isoprenaline and the influence of autonomic reflexes on these reponses. Nine healthy volunteers received infusions and bolus injections of isoprenaline before and after ‘autonomic blockade’ produced by intravenous atropine 0.04 mg kg^-1 and clonidine 300 μg. Heart rate, blood pressures, systolic time intervals and various echocardiographic measures of cardiac contractility were registered. No significant differences in responsiveness to isoprenaline were seen when infusions were repeated on the same day without ‘autonomic blockade’. After ‘blockade’, Δ responses at 1 nmol 1^-1 isoprenaline (infusions) were increased for diastolic blood pressure and decreased for systolic blood pressure and stroke volume. Bolus injections of 2 μg isoprenaline caused enhanced Δ responses after ‘autonomic blockade’ of diastolic blood pressure, left ventricular diameter in systole, ventricular circumferential fibre shortening, mean posterior wall velocity (V_{mean pw}), stroke volume, systemic vascular resistance, electromechanical systole (QS₂) and pre-ejection period. Systolic blood pressure decreased, in contrast to a small increase without ‘blockade’. These findings are explained by differences in haemodynamic effects of isoprenaline and by the dependence of responses on reflexes when isoprenaline is administered in different ways. When heart rate was increased by bolus doses of atropine, in the presence of β-blockade (propranolol), pre-ejection period and left ventricular diameter in systole were unaffected, and V_{mean pw} and ventricular circumferential fibre shortening showed only small increases (compared with alterations induced by isoprenaline). However, left ventricular ejection time, QS₂ and ejection time (by echocardiography), were markedly dependent on heart rate alterations. Thus, pre-ejection period, left ventricular diameter in systole V_{mean pw} and ventricular circumferential fibre shortening are parameters which can be useful in order to evaluate cardiac β-adrenoceptor sensitivity in vivo in man.     

Experimental neurotoxicity of the anorectic fenfluramine

Summary Fenfluramine, an amphophilic compound which is a halogenated derivative of amphetamine, is still used as an anorectic agent for weight reduction, as it acts on the satiety center of the hypothalamus. Holtzman strain rats aged 6 days were daily injected s.c. fenfluramine hydrochloride at the dose of 75 mg/kg body weight. The animals were killed at different time intervals between days 7 and 40, and different parts of the brain were examined by light and electron microscopy. About half of the animals showed intralysosomal membrano-cytoplasmic bodies in the oligodendroglia, neurons, and neuropil, maximally in the animals receiving 8–19 injections. They were seen as concentrically arranged, single-layered lamellae; small dense bodies; or larger heterogeneous bodies. The mechanism of production of such inclusions could be the formation of complexes of this amphophilic compound with tissue phospholipids, or some enzyme-inhibiting action. A marked prominence of dark cells, predominantly oligodendroglia, was also noticed in the brains of experimental animals. Some of these cells appeared to be dark neurons, probably resulting from the serotonin-depleting effect of fenfluramine. A few dark cells were identified as resting microglial cells, while macrophagic reactive microglia were detected in the brains of very young animals. Fenfluramine appears to provide a model for studying neuroglial reactions.Paper presented at the Erwin Riesch symposium on Lysosomal Disorders of the Nervous System, Berlin (Convenor, Prof. Cervos-Navarro); and as poster-talk at the 9th International Congress of Neuropathology, Vienna, September 1982     

Dietary Aspects to Incorporate in the Creation of a Mobile Image-Based Dietary Assessment Tool to Manage and Improve Diabetes

Diabetes is the seventh leading cause of death in United States. Dietary intake and behaviors are essential components of diabetes management. Growing evidence suggests dietary components beyond carbohydrates may critically impact glycemic control. Assessment tools on mobile platforms have the ability to capture multiple aspects of dietary behavior in real-time throughout the day to inform and improve diabetes management and insulin dosing. The objective of this narrative review was to summarize evidence related to dietary behaviors and composition to inform a mobile image-based dietary assessment tool for managing glycemic control of both diabetes types (type 1 and type 2 diabetes). This review investigated the following topics amongst those with diabetes: (1) the role of time of eating occasion on indicators of glycemic control; and (2) the role of macronutrient composition of meals on indicators of glycemic control. A search for articles published after 2000 was completed in PubMed with the following sets of keywords “diabetes/diabetes management/diabetes prevention/diabetes risk”, “dietary behavior/eating patterns/temporal/meal timing/meal frequency”, and “macronutrient composition/glycemic index”. Results showed eating behaviors and meal macronutrient composition may affect glycemic control. Specifically, breakfast skipping, late eating and frequent meal consumption might be associated with poor glycemic control while macronutrient composition and order of the meal could also affect glycemic control. These factors should be considered in designing a dietary assessment tool, which may optimize diabetes management to reduce the burden of this disease.     

基于HART协议的实时设备管理系统

讨论了基于HART协议智能设备的实时管理系统,介绍了HART协议的基本规范,以及如何利用已有集散控制系统（DCS）和工厂信息网络的集成实现实时信息共享,取得了良好的实际效果。     

蠕变局部损伤开裂的有限元模型

建立了蠕变局部损伤法模型,并给出单元进入损伤态的判据和失效的临界拉伸应变条件,局部蠕变损伤理论的实质就是试样是多种不同蠕变性能材料的统一,并由蠕变应力再分布得到证实,应用有限元对双缺口圆试样作了蠕变局部损伤分析,启裂时间和断裂蠕变应变值均与实验结果相吻合。     

Increased Operative Time Impacts Rates of Short-Term Complications After Unicompartmental Knee Arthroplasty

BackgroundPrevious evidence has demonstrated an exacerbating effect of increased operative time on short-term complications in total joint arthroplasty. While the same relationship may be expected for unicompartmental knee arthroplasty (UKA), supporting evidence remains sparse. The purpose of this study is to determine the impact of operative time on short-term complication rates after UKA and determine a critical threshold in operative times after which complications may increase.MethodsThe American College of Surgeons National Surgical Quality Improvement Project was queried from 2007 to 2018 to identify 11,633 UKA procedures that were included in the final analysis. The effect of operative time on complications within 30 days was evaluated using multivariate logistic regression models. Receiver operating characteristics curves and spline regression models were used to identify critical thresholds in operative time that increase the likelihood of short-term complications.ResultsLonger operative times (in minutes) were associated with higher rates of surgical site infection (90.4 ± 26.7 vs 84.8 ± 25.5, P = .003), blood transfusions (94.9 ± 28.6 vs 84.9 ± 25.5, P = .007), as well as reoperation rates (90.8 ± 27.9 vs 84.9 ± 25.5, P = .01), extended hospital length of stay (93.4 ± 29.8 vs 84.5 ± 25.2, P < .001), and mortality (110.4 ± 35.5 vs 84.9 ± 25.5, P = .008). Following multivariate logistic regression, operative time was found to independently predict increased surgical site infection, blood transfusion, myocardial infarction, extended length of stay, and mortality (odds ratio: 1.09 – 1.45, CI: 1.01 – 1.91, all P values <0.02). Receiver operating characteristics curves found an increase in mortality risk during the 30-day postoperative period after 88.5 minutes of operative time, a finding supported by spline regression plots.ConclusionThe present study found a positive correlation between increased operative times and short-term postoperative complication rates after UKA. Despite a statistically significant association with increasing operative time, odds ratios of reported complications are relatively low.     

The association between decision-making skills and subjective decision outcomes among administrative officers in the Swedish Social Insurance Agency

Social insurance administrative officers’ decision-making skills influence their efficiency at work and their general well-being. At work their tasks are characterised by complexity and a need for order and accountability. Moreover, cases should usually be handled and finalised within the imposed time frames. We investigated skills related to decision-making success among social insurance officers. In total, 118 administrative officers at the Swedish Social Insurance Agency (66% response rate) responded to questions on scales and measures relating to cognitive-rational, socio-emotional and time approach features of decision-making skill. In addition, they responded to questions on three scales pertaining to outcomes of everyday decisions in terms of subjective everyday difficulties, tendencies to burnout and depressive symptoms. The results showed that cognitive-rational competence was associated with lower reports of subjective everyday difficulties and depressive symptoms and thereby contributed to the explained variance in decision outcomes. Furthermore, socio-emotional and time approach features of decision-making skills contributed to the explanation for subjective everyday difficulties, tendencies to burnout and depressive symptoms. The results corroborate the basic assumption and usefulness of a broad approach in the definition and assessment of decision-making skills in human service professions in general, and of administrative officers in social insurance agencies in particular. Recommendations for future research and the implications of the results are discussed.