Role of Bio-Based and Fossil-Based Reactive Diluents in Epoxy Coatings with Amine and Phenalkamine Crosslinker

The properties of epoxy can be adapted depending on the selection of bio-based diluents and crosslinkers to balance the appropriate viscosity for processing and the resulting mechanical properties for coating applications. This work presents a comprehensive study on the structure-property relationships for epoxy coatings with various diluents of mono-, di-, and bio-based trifunctional glycidyl ethers or bio-based epoxidized soybean oil added in appropriate concentration ranges, in combination with a traditional fossil-based amine or bio-based phenalkamine crosslinker. The viscosity of epoxy resins was already reduced for diluents with simple linear molecular configurations at low concentrations, while higher concentrations of more complex multifunctional diluents were needed for a similar viscosity reduction. The curing kinetics were evaluated through the fitting of data from differential scanning calorimetry to an Arrhenius equation, yielding the lowest activation energies for difunctional diluents in parallel with a balance between viscosity and reactivity. While the variations in curing kinetics with a change in diluent were minor, the phenalkamine crosslinkers resulted in a stronger decrease in activation energy. For cured epoxy resins, the glass transition temperature was determined as an intrinsic parameter that was further related to the mechanical coating performance. Considerable effects of the diluents on coating properties were investigated, mostly showing a reduction in abrasive wear for trifunctional diluents in parallel with the variations in hardness and ductility. The high hydrophobicity for coatings with diluents remained after wear and provided good protection. In conclusion, the coating performance could be related to the intrinsic mechanical properties independently of the fossil- or bio-based origin of diluents and crosslinkers, while additional lubricating properties are presented for vegetable oil diluents.

Benchmark Study of Epoxy Coatings with Selection of Bio-Based Phenalkamine versus Fossil-Based Amine Crosslinkers

The phenalkamines (PK) derived from cardanol oil can be used as a bio-based crosslinker for epoxy coatings as an alternative for traditional fossil amines (FA). First, the reaction kinetics of an epoxy resin with four PK and FA crosslinkers are compared by differential scanning calorimetry, illustrating a fast reaction rate and higher conversion of PK at room temperature in parallel with a moderate exothermal reaction. Second, the performance of coatings with various concentrations of PK and PK/FA ratios indicates good mixing compatibility between crosslinkers resulting in higher hardness, scratch resistance, hydrophobicity, and abrasive wear resistance of coatings with PK. The superior performance is confirmed over a broad range of resin/crosslinker ratios, facilitating the processing with viscosity profiles depending on the PK type. Although fossil- and bio-based crosslinkers have different chemical structures, the unique linear relationships between intrinsic mechanical properties (i.e., ductility and impact resistance) and coating performance indicate that the degree of crosslinking is a primary parameter controlling coating performance, where PK simultaneously provides high hardness and ductility. In conclusion, the optimization of the processing range for bio-based PK as a crosslinker for epoxy coatings delivers suitable processing conditions and superior mechanical performance compared to traditional amine crosslinkers.

Cost-effectiveness of custom-made insoles versus usual care in patients with plantar heel pain in primary care: cost-effectiveness analysis of a randomised controlled trial

OBJECTIVES

To evaluate the cost-effectiveness of custom-made insoles compared with general practitioner (GP)-led usual care after 26 weeks of follow-up in individuals with plantar heel pain (PHP) from a societal perspective.

DESIGN

Cost-effectiveness analysis of a double-blinded randomised controlled trial.

SETTING

General practice in the Netherlands.

PARTICIPANTS

116 participants with PHP for at least 2 weeks, aged 18-65 years and presenting to the GP.

INTERVENTIONS

Participants were randomised to GP-led usual care (n=46) or referral to a podiatrist for treatment with a custom-made insole (n=70). Participant randomised to a sham insole (n=69) were excluded from this analysis.

PRIMARY AND SECONDARY OUTCOMES

Outcomes comprised pain during rest and activity, and quality of life. Costs included healthcare and lost productivity costs. Statistical uncertainty was estimated using bootstrapping and presented using cost-effectiveness acceptability curves.

RESULTS

Participants in the custom-made insole group experienced statistically significant more pain during activity at 26 weeks than participants in the usual care group (overall effect 1.06; 95% CI 0.36 to 1.75). There were no significant differences between groups in other outcomes. Total societal costs in the custom-made insole group were non-significantly higher than in the usual care group (mean difference €376; 95% CI -€1775 to €2038). The intervention with custom-made insoles was dominated by usual care by the GP (ie, more expensive and less effective) for pain during activity and quality of life outcomes. For the outcome pain at rest, the intervention was more expensive and more effective than usual care. However, the maximum probability of cost-effectiveness was only 0.59 at very high ceiling ratios.

CONCLUSIONS

These findings show that that custom-made insoles are not cost-effective in comparison with GP-led usual care. Clinicians should be reserved in prescribing custom-made insoles for PHP as a primary intervention.

TRIAL REGISTRATION NUMBER

NTR5346.

'Implementing a broad quality of life tool for determining care wishes and needs of older adults living at home

The aim was to investigate the views of stakeholders on the practical relevance of a broad quality of life (QoL) outcome tool for care in older adults: the Extended Quality of Life Tool (EQLT). We conducted individual interviews and focus groups with a variety of stakeholders involved in the care for older adults which were analyzed using a framework analysis. Stakeholders considered relevant: focus on the client perspective; perspective on QoL broader than health; the possibility to take diversity into account; and the possibility to determine a minimum level of QoL. Three facilitators for implementation of the tool were mentioned as well as four barriers. The EQLT can support conversations with clients about their needs and wishes, thus enabling decisions about care services based on a broad set of domains of QoL. Implementation of the tool should take into account the facilitators and barriers identified in the current study.

A phase I study of bendamustine hydrochloride administered day 1+2 every 3 weeks in patients with solid tumours

The aim of the study was to determine the maximum tolerated dose (MTD), the dose limiting toxicity (DLT), and the pharmacokinetic profile (Pk) of bendamustine (BM) on a day 1 and 2 every 3 weeks schedule and to recommend a safe phase II dose for further testing. Patients with solid tumours beyond standard therapy were eligible. A 30-min intravenous infusion of BM was administered d1+d2 q 3 weeks. The starting dose was 120 mg m(-2) per day and dose increments of 20 mg m(-2) were used. Plasma and urine samples were analysed using validated high-performance liquid chromatography/fluorescence assays. Fifteen patients were enrolled. They received a median of two cycles (range 1-8). The MTD was reached at the fourth dose level. Thrombocytopaenia (grade 4) was dose limiting in two of three patients at 180 mg m(-2). One patient also experienced febrile neutropaenia. Lymphocytopaenia (grade 4) was present in every patient. Nonhaematologic toxicity including cardiac toxicity was not dose limiting with this schedule. Mean plasma Pk values of BM were tmax 35 min, t(1/2) 49.1 min, Vd 18.3 l m(-2), and clearance 265 ml min(-1) m(-2). The mean total amount of BM and its metabolites recovered in the first micturition was 8.3% (range 2.7-26%). The MTD of BM in the present dose schedule was 180 mg m(-2) on day 1+2. Thrombocytopaenia was dose limiting. The recommended dose for future phase II trials with this schedule is 160 mg m(-2) per day.

Methotrexate loaded SAE coated coronary stents reduce neointimal hyperplasia in a porcine coronary model

OBJECTIVE

To evaluate the effect of stent based methotrexate delivery on neointimal hyperplasia.

METHODS

Stainless steel coronary stents and biological polymer coated (SAE) stents were randomly implanted in coronary arteries of pigs with a stent to artery ratio of 1.1:1. The pigs were killed after five days (10 stents) or four weeks (20 stents). Second, stainless steel coronary stents were dip coated in a 10 mg/ml methotrexate-SAE polymer solution, resulting in a total load of 150 microg methotrexate/stent. SAE coated stents and methotrexate loaded stents were randomly implanted in porcine coronary arteries with a stent to artery ratio of 1.2:1 and followed up to four weeks.

RESULTS

SAE coated stents and bare stents elicited a similar tissue response at five days. At four weeks, neointimal hyperplasia induced by the coated stents was less pronounced than with the bare stents (1.32 (0.66) v 1.73 (0.93) mm2, p > 0.05). In vitro drug release studies showed that 50% of the methotrexate was released in 24 hours, and all drug was released within four weeks. No impact on vascular smooth muscle cell proliferation or viability was observed in in vitro cell cultures. At four weeks the arteries with methotrexate loaded stents had decreased peristrut inflammation and neointimal hyperplasia (1.22 (0.34) v 2.25 (1.28) mm2, p < 0.01).

CONCLUSIONS

SAE coating had an excellent biocompatibility with vascular tissue. Stent based delivery of methotrexate in the SAE coating effectively reduced neointimal hyperplasia in a porcine coronary stent model, potentially due to reduced peristrut inflammation.

Combined endurance/resistance training reduces plasma TNF-alpha receptor levels in patients with chronic heart failure and coronary artery disease

AIMS

Physical reconditioning of patients with chronic heart failure (CHF) improves exercise capacity and restores endothelial function and skeletal muscle changes. The effects of 4 months combined endurance/resistance exercise training on cytokines and cytokine receptors in patients with CHF were studied. In addition, changes in submaximal and maximal exercise performance were addressed.

METHODS AND RESULTS

Twenty-three patients with stable CHF due to coronary artery disease (CAD, n=12) or idiopathic dilated cardiomyopathy (IDCM, n=11) were trained for 4 months. Blood sampling for measurement of plasma concentrations (ELISA) of interleukin (IL)-6, tumour necrosis factor (TNF)-alpha, soluble TNF receptor 1 (sTNFR1) and 2 (sTNFR2), as well as cardiopulmonary exercise testing were performed at baseline and after 4 months. Training induced a significant decrease in sTNFR1 (P=0.02) for the total population, and in both sTNFR1 (P=0.01) and sTNFR2 (P=0.02) concentrations for the CAD group only. IL-6 and TNF-alpha levels were not altered. Cytokine concentrations remained unchanged in an untrained age- and sex-matched control group. NYHA functional class, submaximal and maximal workrate were significantly improved in both patient groups. Oxygen uptake at the anaerobic threshold (P=0.002) and at peak exercise increased in the CAD patients only (P=0.008).

CONCLUSION

Besides an overall beneficial effect on exercise capacity, combined endurance/resistance exercise training has an anti-inflammatory effect in patients with CHD and CAD.

Effect of stenting on coronary flow velocity reserve: comparison of coil and tubular stents

OBJECTIVE

To determine whether coil stents are as effective as tubular stents in improving coronary flow velocity reserve (CFVR) after stent deployment.

METHODS

Distal CFVR was measured with a 0. 014 inch Doppler guide wire before and after stenting in 33 patients. A coil stent was implanted in 16 patients and a tubular stent was used in 17 patients. Coronary flow velocity within the stent was also recorded during a slow pullback.

RESULTS

Following placement of the stents, the percentage diameter stenosis was similar for both the tubular and coil stents (mean (SE) 11 (2)% v 13 (2)%, NS). However, distal CFVR was higher after stenting with a tubular stent compared with a coil stent (2.46 (0.13) v 1.96 (0.14), p < 0.05). Furthermore, pullback through the stent detected a major flow velocity increase within coil stents but not in tubular stents (83 (24)% v 5 (5)%, p < 0.05).

CONCLUSIONS

In spite of similar angiographic improvement, placement of coil stents was associated with inferior functional results compared with tubular stents. The flow velocity acceleration within the coil stents suggests the presence of a residual narrowing within the stent, which is not appreciated on angiography.

Determinants and prognostic implications of persistent ST-segment elevation after primary angioplasty for acute myocardial infarction: importance of microvascular reperfusion injury on clinical outcome

BACKGROUND

Despite early recanalization of an occluded infarct artery, reperfusion at the level of the microcirculation may remain impaired owing to a process of microvascular reperfusion injury.

METHODS AND RESULTS

Microvascular reperfusion injury was studied in 91 patients with acute myocardial infarction (AMI) by evaluation of the resolution of ST-segment elevation after successful PTCA. Impaired microvascular reperfusion, defined as the presence of persistent (>/=50% of initial value) ST-segment elevation (ST >/=50%) at the end of coronary intervention, was observed in 33 patients (36%) and was independently correlated with low systolic pressure on admission and high age. Patients >/=55 years of age with systolic pressures </=120 mm Hg were at high risk for development of impaired reperfusion compared with patients not meeting these criteria (72% versus 14%, P<0.001). Impaired microvascular reperfusion was associated with a more extensive infarction and worse clinical outcome at the 1-year follow-up: cardiac death rate, 15% versus 2% (ST >/=50% versus ST <50%, P=0.01); nonfatal MI rate, 9% versus 2% (P=0.1); and total major adverse cardiac event (MACE) rate, 45% versus 15% (P<0.005). ST >/=50% was the most important independent determinant of MACE with an adjusted risk ratio of 3.4.

CONCLUSIONS

Impaired microvascular reperfusion, as evidenced by ST >/=50% after successful recanalization, occurs in more than one third of our AMI patients, especially in older patients with low systolic pressure. Its detrimental implications on clinical outcome reinforce the need to develop adjunctive agents that attenuate the process of reperfusion injury.

User-friendly and low-cost computer system for immediate review, analysis, and reconstruction of intracoronary ultrasound images

Rapid review, digital recording, on-line quantification, and three-dimensional reconstruction are all essential in the evaluation of intracoronary ultrasound images during coronary interventions. We describe a low-cost method that offers all these necessary features. The proposed method uses the QuickTime compatible video digitizers of standard multimedia Apple Macintosh or PowerPC desktop computers and the freeware software Object Image 1.60.

Coronary flow reserve during coronary angioplasty in patients with a recent myocardial infarction: relation to stenosis and myocardial viability

OBJECTIVES

In the present study, we examined post-stenotic coronary flow before and after percutaneous transluminal coronary angioplasty (PTCA) in patients with and without a recent myocardial infarction (MI) and related it to stenosis severity and residual viability.

BACKGROUND

Post-stenotic coronary blood flow velocity reserve (CFVR) has been used with success to estimate functional stenosis severity in patients with stable angina. However, in patients with a recent MI, the impaired coronary vasodilator response of the reperfused myocardium may substantially alter the flow dynamics of the infarct-related artery.

METHODS

Distal coronary flow velocities were recorded before and after PTCA in 36 patients at day 13 +/- 7 (mean +/- SD) after acute MI and in 38 patients without MI. The CFVR was assessed by the ratio of distal hyperemic to baseline average peak velocity, using a 0.014-in. Doppler guide wire. Stenosis severity was analyzed by quantitative coronary angiography, and infarct size was assessed scintigraphically.

RESULTS

For similar angiographic stenosis severity, pre- and post-PTCA values of CFVR were significantly lower in patients with than without MI: 1.22 +/- 0.26 versus 1.50 +/- 0.45 before PTCA (p < 0.05) and 1.72 +/- 0.43 versus 2.21 +/- 0.74 after PTCA, respectively (p < 0.01). Although CFVR increased significantly (p < 0.0001) after angiographically successful PTCA in both study groups, abnormal CFVR (< or = 2.0) was still observed in 80% of patients with MI and in 44% of those without MI (MI vs. no MI, p = 0.001). Patients with an extensive infarction (relative infarct size > or = 50%) and those with a small infarction (relative infarct size < 50%) had comparable levels of post-PTCA CFVR (1.6 +/- 0.3 vs. 1.8 +/- 0.5, p = NS). Among a variety of factors, angiographic stenosis severity was the most important determinant of CFVR in both study groups.

CONCLUSIONS

In patients with a recent MI, CFVR was significantly lower than in those without MI, both before and after PTCA. Besides the presence of this postreperfusion-related impairment of the coronary vasodilating response, CFVR was mainly influenced by stenosis severity and not by residual viability.

External vibration interference of activity based rate responsive pacemakers

The change of the pacing rate in response to external vibration interference was assessed in four rate responsive pacemakers with a piezoelectric crystal (Medtronic Activitrax 8403, Siemens Sensolog 3, Biotronik Ergos 01, and Medtronic Legend 8417) and one with an accelerometer (CPI Excel VR 1119). They were tested in the laboratory. External vibration was simulated in vitro by exposing the different pacemakers to a controlled sinusoidal vibration force generated by a Millar pressure vibration amplifier type MGM-30 (Millar Instruments, Inc., Houston, TX, USA). All pacemakers were programmed at standard settings. Two types of vibration forces were applied: (1) one with varying amplitude but with constant vibration frequency; and (2) one with varying frequency but with constant vibration amplitude. In this manner curves of pacing rate versus vibration forces versus vibration frequency were obtained. High vibration forces and low vibration frequencies were associated with the highest pacing rate response. In this experimental setting, the pacemaker based on the accelerometer principle apparently was the least sensitive to high frequency vibrations, which are known to be related to environmental interference. It also seemed more appropriately responsive in the lower frequency range, which is more appropriate for the detection of true physiological activity.

Paradoxical vasoconstriction as result of acetylcholine and serotonin in diseased human coronary arteries

In experimental atherosclerosis, impairment of endothelium-dependent vasodilation results in an unmasking of potent vasoconstrictor responses to serotonin, a substance released by aggregating platelets. To determine whether similar changes occur in diseased human coronary arteries, the responses to selective intracoronary infusions of acetylcholine and serotonin (both endothelium-dependent vasodilators) and to isosorbide dinitrate (a dilator directly acting on the smooth muscle) were assessed by quantitative coronary arteriography in 16 patients with angiographically normal coronary arteries, in 10 patients with minimal (less than 30% narrowing) and in five patients with more advanced (greater than 50% narrowing) coronary atherosclerosis. Acetylcholine induced constriction in diseased coronary arteries, but in patients with normal coronary arteriograms, it caused dilatation in seven patients (smooth dilators) and constriction in nine patients (smooth constrictors). In the smooth dilators, however, serotonin evoked no significant changes (+1.4 +/- 4.1%), whereas in the smooth constrictors and in patients with diseased coronary arteries, serotonin caused dose-dependent constriction. The vasoconstrictor responses to serotonin were similar in patients with minimal (-26.5 +/- 4.7%) and more advanced atherosclerosis (-30.9 +/- 5.3%). In one patient with coronary artery disease, serotonin caused a temporary coronary occlusion. All other patients dilated in response to isosorbide dinitrate. The vasomotor responses to acetylcholine and to serotonin were thus shown to be completely in parallel.

CONCLUSION

impairment of endothelium-dependent vasodilation unmasks potent vasoconstrictor responses to serotonin both in early and advanced coronary atherosclerosis. These changes may play an important role in the pathogenesis of a dynamic coronary artery stenosis.

Intracerebral hemorrhage after lumbar myelography with iohexol: report of a case and review of the literature

Intracranial hemorrhage is an uncommon complication of dural puncture. In most instances, hematomas are subdural; they may be unilateral or bilateral. Rarely are intraparenchymal cerebral hemorrhages related to dural puncture. This report describes a delayed occurrence of bilateral intraparenchymal hemorrhages in a 38-year-old woman 7 days after lumbar myelography with iohexol. A review of the literature is presented.

Modification of the late asthmatic reaction by hyposensitization in asthmatic children allergic to house dust mite (Dermatophagoides pteronyssinus) or grass pollen

The frequency and severity of the late asthmatic reaction (LAR) was studied in asthmatic children allergic to house dust mite (HDM) or grass pollen (GP) with and without hyposensitization (HS). The four groups were comparable according to their severity of asthma. All children were allergic to HDM (Dermatophagoides pteronyssinus) or GP according to history, skin testing and specific IgE determination via the RAST. The LAR occurred less frequently (29% versus 73%) (P less than 0.001) and was less severe in children receiving HS. The difference was significant between the children allergic to HDM as well as between children allergic to GP. The immediate asthmatic reaction (IAR) was also less severe in children allergic to HDM who received HS, compared to those who never received HS, (P = 0.033) although the PD20 of the HDM challenge (PD20HDM) was not different between the two groups. In children allergic to GP, there was no difference in PD20 of the GP challenge (PD20GP) or in severity of the IAR, whether the children received HS or not. There was no difference between the PD20HDM in patients who developed a LAR and in patients who did not. There was no relation between the type of asthmatic reaction following the allergen provocation test and the level of circulating immune complexes (CIC) and the level of house dust mite-specific IgG (IgGHDM) or grass pollen-specific IgE (IgGGP) in the different groups, determined before the challenge. There was a decrease in the level of IgG containing CIC (IgGCIC) during the LAR. It is concluded that the LAR occurs less frequently and is less severe in asthmatic children who receive HS.

Nebulization treatment with saline compared to bromhexine in treating chronic sinusitis in asthmatic children

Twenty children aged 3 to 14 years with a history of bronchial asthma complicated by chronic sinusitis were studied in a double-blind study. Patients received, at random, over a period of 2 weeks, either 2 ml saline or 2 ml bromhexine (2 mg/ml) t.i.d. by means of a home nebulizer. A significant decline of clinical symptoms during both nebulization treatments as compared to the pretreatment symptom score was observed (mean score of 1.5 +/- 0.7 and 0.5 +/- 0.8, respectively, P less than 0.01). Both types of nebulization were equally efficient in reducing the symptom score. Radiological abnormalities were significantly more reversed after saline nebulization as compared with bromhexine (P less than 0.05), although both treatments showed radiological improvement (P less than 0.01). The present study indicates that nebulization with saline may have some beneficial effect on chronic sinusitis in asthmatic children. Bromhexine was not superior to saline for this purpose.

Prevalence of Candida albicans in patients receiving total parenteral nutrition

The prevalence of Candida albicans was quantitatively compared in 74 surgical patients during and after total parenteral nutrition (TPN). Suppression of oral food intake is probably responsible for the decrease of the C. albicans population in the mouth. On the contrary anal swabs were more often positive for C. albicans during TPN. This may be due to local conditions as was observed in a group of patients who were not given TPN but were also immobilized for a long period.