The influence of protein solubilisation, conformation and size on the burst release from poly(lactide-co-glycolide) microspheres.

Encapsulation of proteins in poly(lactide-co-glycolide) microspheres via emulsion is known to cause insoluble protein aggregates. Following protein emulsification and encapsulation in PLGA microspheres, we used circular dichroism to show that the recoverable soluble protein fraction also suffers subtle conformational changes. For a panel of proteins selected on the basis of molecular size and structural class, conformational stability measured by chemical denaturation was not indicative of stability during emulsion-encapsulation. Partial loss of structure was observed for alpha-helical proteins released from freeze-dried microspheres in aqueous buffer, with dramatic loss of structure for a beta-sandwich protein. The addition of sucrose (a lyoprotectant) did not prevent the loss of protein conformation upon encapsulation. Therefore, the conformational changes seen for the released soluble protein fraction originates during emulsification rather than microsphere freeze-drying. Analysis of the burst release for all proteins in buffer containing denaturant or surfactant showed that the degree of protein solubilisation was the dominant factor in determining the initial rate and extent of release. Our data for protein release into increasing concentrations of denaturing buffer suggest that the emulsion-denatured protein fraction remains insoluble; this fraction may represent the protein loss encountered upon comparison of protein encapsulated versus protein released.     

Utility of the PFA-100 as a screening test of platelet function: an audit of haemostasis laboratories in Australia and New Zealand.

The PFA-100 is a relatively new laboratory instrument, first described in 1995. There have since been numerous studies assessing its utility as a screening tool for platelet dysfunction and/or von Willebrand's disease (VWD). The PFA-100 displays variable sensitivity to different types of platelet disorders, as well as to antiplatelet medication (e.g. aspirin), with similar caveats for monitoring of primary haemostasis-promoting therapies in platelet dysfunction. There is therefore considerable uncertainty regarding its utility within this context, and we have accordingly performed an audit of usage among participants of the Royal College of Pathologists of Australasia Quality Assurance Program. Of 105 laboratories surveyed, 40 responded that they performed platelet function testing, with 26 (65%) further indicating they utilized the PFA-100. We report a wide variety of laboratory usage among these users, including numbers of tests performed [annual median (range) = 270 (15-6000)], sources of requests (clinical sources and localities), testing criteria and follow-up action. Most tests were completed within 4 h of collection, as recommended by the manufacturer, and most tests were performed as a replacement, or as a preliminary screen of platelet function (i.e. classical aggregation). Most abnormal findings, however, were attributed to antiplatelet medication such as aspirin.     

Cross-calibration of dual-energy X-ray densitometers for a large, multi-center genetic study of osteoporosis

Osteoporosis is a common disease with a strong genetic component characterized by reduced bone mass and an increased risk of fragility fractures. Bone mineral density (BMD) is the most important determinant of osteoporotic fracture risk, but the genes responsible for BMD regulation and fracture are incompletely defined. To enable multi-center studies to examine the genetic influences on BMD there is a requirement to standardize measurements across different manufacturers of bone densitometers, different versions of machines and different normative ranges. This paper describes a method developed to allow near-identical subjects with low age-adjusted BMD (based on Z-scores) to be recruited in 17 centers using 27 different densitometers. Cross-calibration was based on measurements using a European spine phantom circulated to all centers and measured ten times on each individual machine. From theses values an individual exponential curve, based on nominal versus observed BMD, was derived for each machine. As expected, there were large and significant variations in nominal BMD values, not only between scanners from different manufacturers but also between different versions of scanners from the same manufacturer. Hologic scanners tended to underestimate the nominal BMD, while Lunar scanners overestimated the value. Norland scanners gave mixed values over estimating BMD at the lower nominal value (0.5 g/cm²) while underestimating the value at the higher value (1.5 g/cm²). The validity of the exponential equations was tested using hip and spine measurements on 991 non-proband women from a familial osteoporosis study (FAMOS). After cross-calibration there was a considerable reduction in variation between machines. This observation, coupled with the absence of a similar reduction in variation attributable to a linear regression on age, demonstrated the validity of the cross-calibration approach. Use of the cross-calibration curves along with a standard normative range (in the case of this study, the Hologic normative range) allowed age-specific Z-scores to be used as an inclusion criterion in this genetic study, a method that will be useful for other trials where age-specific BMD inclusion criteria are required.     

Psychological distress among female spouses of male at-risk drinkers.

The consequences of alcoholism on the mental health of spouses of lifetime at-risk drinkers are only known from studies on alcoholics already in treatment. A retrospective analysis was conducted using data from a Quebec community health survey. The purpose of this study was twofold. First, our goal was to ascertain the mental health of female spouses living with a male lifetime at-risk drinker. Secondly, we wanted to examine the relationship between male lifetime at-risk drinkers (aged 30-54 years) and the psychological distress of their nondrinking female spouses. Lifetime at-risk drinking, for the purposes of this study, was defined as having at least two positive answers to the CAGE questionnaire. Couples wherein both spouses were deemed not at-risk for problem drinking by the CAGE instrument (0 or 1 positive answer) formed the control group. Psychological distress was measured using the Indice de Détresse Psychologique de l'Enquête Santé Québec (Préville, M., Boyer, R., Potvin, L., Perreault, C., & Légaré, G. (1992). La détresse psychologique: détermination de la fiabilité et de la validité de la mesure utilisée dans l'enquête Santé Québec. Cahier de recherches #7, Montréal, Santé Québec.). It measures symptoms of anxiety, depression, aggressivity, and cognitive impairments. Scores of >or=22 (out of 100) were indicative of a high level of psychological distress. This study confirmed higher levels of psychological distress in female spouses of male lifetime at-risk drinkers in the general population. An exploratory study examined the association between the psychological distress of female spouses and each of the following nine independent variables: male partner lifetime at-risk drinker, stressful life events, job situation, socioeconomic status, perceived health status, presence of children less than 15 years, length of the marital relationship, presence of a confidant, and availability of social support. Lifetime at-risk drinking is a risk factor for the spouse's psychological distress. An examination of the demographic characteristics related to alcohol intake in male lifetime at-risk drinkers is also described in this study.     

Iowa's High School High Tech Goes to College Program: Preparing Students with Mild Disabilities for Careers in Technology

This paper describes an innovative approach to preparing high school students with mild disabilities for challenging careers in high tech industries, called High School High Tech (HSHT). Iowa's HSHT Goes to College program has three central elements, each of which is discussed in this paper: High School Preparation—assisting students in identifying a suitable high tech career goal; Higher Education Preparation and Supports—assisting students in selecting college/training programs that match their career goal, and in successfully completing their postsecondary programs; Workforce Entry Assistance—linking students with employers and launching their high tech careers. The paper concludes with a presentation of outcomes to date and recommendations for program enhancements. The information presented here is intended to assist education and rehabilitation professionals interested in establishing similar efforts across the nation.     

Lung Transplant Metalloproteinase Levels Are Elevated Prior to Bronchiolitis Obliterans Syndrome

Parenchymal disease in the allograft lung is associated with interstitial remodeling believed to be mediated by matrix metalloproteinases (MMPs). Recent studies suggest high levels of MMP-9 are associated with bronchiolitis obliterans syndrome (BOS) in lung transplant recipients. Since BOS occurs late in the posttransplant period and may be preceded by episodes of acute rejection or infection, which are associated with interstitial remodeling, we examined MMP profiles in allograft bronchoalveolar lavage (BAL) fluid in the early posttransplant period (preceding BOS). Gelatin zymography, protein array analysis and specific ELISA on BAL fluids from transplanted lungs indicated that MMP-8, MMP-9 and TIMP-1 were strongly expressed in allograft BAL fluid from stable patients, or those with infection or rejection compared to BAL fluid from normal volunteers. Elevated expression of MMP-8, MMP-9 and TIMP-1 occurred early, and was sustained for the 3.2 years covered in this study. Elevations of MMP-8, MMP-9 and TIMP-1 in the first 2 years posttransplant appear to be associated with lung transplantation itself, and not infection or rejection. These data suggest that ongoing and clinically silent MMP activity could perpetuate progressive disease in the allograft lung.