Crystallization of a copolyester in microlayers and blends with polycarbonate

The crystallization behavior of coextruded microlayered sheets comprised of 657 alternating layers of polycarbonate (PC) and a miscible copolyester of mainly 1,4-cyclohexanedimethanol and terephthalic acid (KODAR) was investigated as a function of annealing time when the KODAR was crystallized isothermally from the glass at 195°C. Comparisons were made with crystallization of KODAR alone, and with crystallization of KODAR from melt blends with PC. The kinetics of crystallization and the morphology of the crystallized KODAR were characterized with differential scanning calorimetry, and by examination of thin sections microtomed from annealed specimens in the polarized light microscope and the transmission electron microscope. The growth rate of small, birefringent KODAR spherulites was non-linear, and was strongly affected by diffusion of PC into the KODAR layers. Diffusion of amorphous PC into the KODAR layers retarded nucleation and spherulite growth and decreased spherulite density. The effect became more pronounced as the KODAR layer thickness was reduced. Spherulities nucleated randomly throughout the KODAR layers in the PC/KODAR 20/80 (w/w) microlayer and grew rapidly to form a continuous layer of impinged spherulites. In contrast, spherulites in the PC/KODAR 40/60 and 60/40 microlayers nucleated and grew along the center of the KODAR layers where the KODAR concentration was highest.     

The Effect of High-Dose Ascorbate Supplementation on Plasma Lipoprotein(a) Levels in Patients With Premature Coronary Heart Disease

Study Objective . To determine the efficacy of high-dose ascorbate supplementation in lowering lipoprotein(a) [Lp(a)] levels in patients with premature coronary heart disease (CHD). Design . Randomized, double-blind, placebo-controlled trial. Setting . Outpatient clinic. Patients . Forty-four patients with documented premature CHD. defined as confirmed myocardial infarction and/or angiographically determined stenosis of 50% or greater in at least one major coronary artery before age 60 years. Interventions . Patients were block randomized on the basis of age, gender, and screening Lp(a) concentrations to receive ascorbate 4.5 g/day or placebo for 12 weeks. Measurements and Main Results . High-dose ascorbate was well tolerated and produced a marked elevation in mean plasma ascorbate levels (+1.2 mg/dl; p<0.001). Multiple linear regression analysis revealed no significant effect of supplementation on postintervention Lp(a) levels (p=0.39) in a model that included treatment group assignment, and baseline Lp(a) levels. Conclusions . Our findings do not support a clinically important lowering effect of high-dose ascorbate on plasma Lp(a) in patients with premature CHD.     

Assessing quality of life in primary biliary cirrhosis.

BACKGROUND AND AIMS: Assessment of health-related quality of life (HRQOL) is not routinely reported in the literature on chronic liver disease (CLD). Few studies have examined quality of life (QOL) in patients with primary biliary cirrhosis (PBC) despite its significant functional impact. One of the reasons for the lack of HRQOL measurement in patients with PBC may be the absence of a well-recognized and widely used measure that clinicians can use in ordinary clinical practice. The aim of this study is to evaluate HRQOL measures used in patients with PBC and examine the suitability of the measures for these patients. METHODS: A literature search identified reports that focused on any aspect of QOL in patients with PBC. Key texts were identified containing generic, domain-specific, and condition-specific measures. The identified measures were systematically evaluated for appropriateness, acceptability, reliability, validity, precision, and responsiveness. RESULTS: Twenty measures were identified from 9 key texts. Six of the measures were previously validated generic measures; 10 were domain-specific measures previously used to measure fatigue, depression, and psychological distress in general and psychiatric populations; and 4 measures had been developed in patients with CLD. Reporting of reliability and validity generally was consistent for all measures used. However, reporting of the remaining criteria was variable, particularly in relation to responsiveness over time and acceptability of the measures to patients with PBC. CONCLUSIONS: A clearer and more rigorous approach is needed in reporting the properties of HRQOL measures used in patients with PBC to help clinicians decide which measures are most suitable for these patients.     

Diagnosis and management of anaphylaxis

ANAPHYLAXIS IS A SEVERE SYSTEMIC ALLERGIC reaction that is potentially fatal. It requires prompt recognition and immediate management. Anaphylaxis has a rapid onset with multiple organ–system involvement and is mostly caused by specific antigens in sensitized individuals. Reactions typically follow a uniphasic course, however, 20% will be biphasic in nature. The second phase usually occurs after an asymptomatic period of 1–8 hours, but there may be a 24-hour delay. Protracted anaphylaxis may persist beyond 24 hours. Concurrent β-blocker therapy may adversely affect the response to management. Epinephrine is the treatment of choice and should be administered immediately. Secondary measures include circulatory support, H₁ and H₂ antagonists, corticosteroids and, occasionally, bronchodilators. Post-treatment observation of these patients is necessary, and they should remain within ready access of emergency care for the following 48 hours.     

Assessment of sublingual immunotherapy efficacy in children with house dust mite-induced allergic asthma optimally controlled by pharmacologic treatment and mite-avoidance measures

Although several studies have demonstrated the efficacy of subcutaneous immunotherapy in allergic asthma, few have shown the same benefit using sublingual immunotherapy (SLIT) in asthmatic patients. This study was conducted to assess the efficacy of house dust mite (HDM) SLIT in addition to allergen avoidance and standard pharmacologic treatment. A double-blind, placebo-controlled trial was performed in 111 children (aged 5-15 yr) with HDM-induced mild-to-moderate asthma. After a 4-week baseline phase, patients were randomly assigned to receive SLIT with tablets of HDM extract (n = 55) or placebo (n = 56) for 18 months. Pharmacologic treatment was adjusted every 3 months following a step-down approach. Asthma symptom scores, reduction in use of inhaled corticosteroids and inhaled beta(2)-agonists, rhinitis symptoms, lung function tests, skin sensitivity to HDM, dust mite-specific immunoglobulin (Ig) E and IgG(4), and quality of life (QoL) were assessed during the study. After 18 months of treatment, diurnal and nocturnal asthma symptoms scores did not show significant differences between SLIT and placebo groups. Inhaled corticosteroids and inhaled beta(2)-agonists use was reduced in both groups without significant differences between groups. There were no significant differences in lung function (forced expiratory volume in 1 s and peak flow rate variations) between groups. Rhinitis symptom score decreased in both groups, with no difference between the two groups. The severity dimension of QoL was significantly improved in the SLIT group (age 6-12 yr). SLIT induced a significant reduction of skin sensitivity to HDM (p < 0.01) and a significant increase in HDM-specific IgE and IgG(4) antibodies (p < 0.001) in the SLIT group compared with the placebo group. SLIT was well tolerated with mild/moderate local adverse events. No severe systemic reactions were reported. This study indicates that, when mild-moderate asthmatic children are optimally controlled by pharmacologic treatment and HDM avoidance, SLIT does not provide additional benefit, despite a significant reduction in allergic response to HDM. Under such conditions, only a complete, but ethically unfeasible, discontinuation of inhaled corticosteroid would have demonstrated a possible benefit of SLIT.     

Government advice on peanut avoidance during pregnancy – is it followed correctly and what is the impact on sensitization?

BACKGROUND: In 1998, the UK government issued precautionary advice that pregnant or breast-feeding women with a family history of atopy, may wish to avoid eating peanuts during pregnancy and lactation. This study aimed to assess the compliance with this recommendation and investigate its impact upon peanut sensitization. METHODS: A total of 858 children born immediately after the advice were followed for 2 years and assessed for peanut sensitization. A standardized questionnaire was used to ascertain history of atopy and maternal exposure to peanuts during pregnancy. Following parental consent children were skin prick tested to assess sensitization to peanuts. RESULTS: Sixty-five per cent of mothers had avoided peanuts during pregnancy. Forty-two per cent of the mothers had heard about the government advice, and half modified their diet as a consequence. Neither maternal nor family history of atopy had any significant effect on peanut consumption. Parity did play a role, and mothers having their first child were twice as likely to change their diet (P<0.001). Mothers of 77% of the children sensitized to peanuts had avoided peanuts during pregnancy. In this cohort study maternal consumption of peanut during pregnancy was not associated with peanut sensitization in the infant. CONCLUSIONS: The majority of mothers in this cohort avoided peanut consumption during pregnancy. It is likely that either the government advice is misunderstood by mothers, or that those who communicate the advice have not fully explained who it is targeted at.     

Preparing faculty to use and develop computer-based instructional materials in nursing

This paper identifies the need for more specific guidelines in preparing faculty to use and develop computer-based instructional materials. Cory's model for faculty development is described and planning considerations are outlined. Finally, components of this multifaceted approach to faculty development—identifying available resources, emphasizing the current uses of computers, providing computer literacy/faculty awareness sessions, focusing on the instructional use of microcomputers, collaboration, and communication—are discussed.     

Legionnaire's disease: a current update.

Legionnaire's disease was first identified and described in January 1977. Even today, it is often regarded as an unusual or exotic disease, when in fact it is a very common form of community and nosocomial acquired pneumonia. The major roles of the acute care nurse, including patient health education; psychosocial needs of the patient; and strategies for disease prevention and control, are discussed.