Establishment of a system to standardize acceptability criteria for alanine aminotransferase activity in donated blood

A multilaboratory study was conducted to develop a system for standardizing alanine aminotransferase (ALT) acceptability criteria ("cutoffs") for donated blood. Without standardized cutoffs, each laboratory must develop its own cutoff, and this may not make optimal use of ALT testing to reduce transmission of non-A, non-B hepatitis (NANB). Defining an ALT acceptability criterion in absolute terms is necessary because relative cutoffs based on local donor populations may be affected by the prevalence of NANB in each community. This study involved 16 laboratories using 23 different analytic systems. The ALT results of the analysis of a plasma reference sample could be used to translate mathematically a single, absolute cutoff to units applicable to each analytic system. The distribution of ALT results in 1.4 million donations from across the country was established; basing the cutoff on this sample avoids the problems inherent in using a local donor base to establish a cutoff. We propose the implementation of a system to standardize ALT acceptability criteria to an activity level defined by analysis of a nationwide donor sample.     

Reference intervals for testosterone, androstenedione and SHBG levels in healthy females and males from birth until old age

The measurement of androgen levels is important in the follow-up of sexual development and in the diagnosis of disturbances of the gonadal function in children and adults. The aim of this study was to evaluate the age dependence of the serum concentrations of testosterone, androstenedione, and SHBG from birth until old age using the IMMULITE 2000 automated assay system (DPC, Los Angeles). Testosterone and androstenedione median levels were very high during the first weeks of life due to residual maternal hCG and decreased to low basal levels around the detection limit of the assay. With the onset of puberty around the age of 10 years both parameters increased strongly, reaching a maximum at about 17 years (testosterone: > 20-fold in boys, 2-fold in girls; androstenedione: 10-fold in boys, 5-fold in girls). In both girls and boys, we measured a decline in the SHBG medians during sexual maturation. This decline was more pronounced in boys (median 78.3 to 26.2 nmol/l from Tanner stage 1 to 5) since the higher androgen levels are thought to down-regulate SHBG. In male adults a continuous decrease was seen for testosterone from a median of 16.1 nmol/l in age group 21-30 years to 9.7 nmol/l in the age group > 70 years. In women the testosterone levels which were only about 5% of that of men from the same age group decreased only slightly, starting from a median of 0.9 to 0.6 nmol/l. In both sexes androstenedione levels decreased continuously during aging. In contrast to the androgen levels, the median SHBG levels increased steadily in men from 20.8 to 44.5 nmol/l, while the median SHBG levels in women decreased from 78.3 to 44.5 nmol/l in the age group of 61-70 years. Interestingly, the SHBG levels rose again in women of the group > 70 years. The reference intervals elaborated here may help in the assessment of the status of sexual development, and to diagnose pathologies of the gonadal axis or hypogonadism during aging.     

State of the art and future directions of scaffold-based bone engineering from a biomaterials perspective

Scaffold-based bone tissue engineering aims to repair/regenerate bone defects. Such a treatment concept involves seeding autologous osteogenic cells throughout a biodegradable scaffold to create a scaffold-cell hybrid that may be called a tissue-engineered construct (TEC). A variety of materials and scaffolding fabrication techniques for bone tissue engineering have been investigated over the past two decades. This review aims to discuss the advances in bone engineering from a scaffold material point of view. In the first part the reader is introduced to the basic principles of bone engineering. The important properties of the biomaterials and the scaffold design in the making of tissue engineered bone constructs are discussed in detail, with special emphasis placed on the new material developments, namely composites made of synthetic polymers and calcium phosphates. Advantages and limitations of these materials are analysed along with various architectural parameters of scaffolds important for bone tissue engineering, e.g. porosity, pore size, interconnectivity and pore-wall microstructures.     

Effects of vision and arm position on amplitude of arm postural tremor in patients with multiple sclerosis

Feys P, Helsen WF, Liu X, Lavrysen A, Nuttin B, Ketelaer P. Effects of vision and arm position on amplitude of arm postural tremor in patients with multiple sclerosis. Arch Phys Med Rehabil 2004;85:1031-3.

Objectives

To quantify the effects of vision and arm position on arm postural tremor, comparisons were made between flexed and extended arm positions performed with the eyes open and closed.

Design

Case-control study.

Setting

National multiple sclerosis (MS) center in Belgium.

Participants

Sixteen patients (32 arms) with MS who had intention tremor and 16 healthy controls (32 arms).

Interventions

Not applicable.

Main outcome measure

The amplitude of postural tremor was assessed by a magnetic position sensor attached to the index finger.

Results

The amplitude of postural tremor was not influenced by changes in visual condition or different arm positions. Both healthy controls and MS patients made more directional changes in the flexed, compared with the extended arm position.

Conclusions

The amplitude of the arm postural tremor in MS is independent of vision and arm position. Selecting 1 arm position is sufficient to assess postural tremor amplitude.     

Utilization of anticoagulants and outcomes in STEMI patients undergoing PPCI in the US hospitals: Bivalirudin,heparin plus GPI or heparin alone?

Objective. Despite major trials showing the opposite, one of three small randomized trials conducted outside the US has raised questions about whether heparin alone is a viable antithrombotic strategy for primary percutaneous coronary interventions (PPCI). We determined the frequency and in-hospital outcomes of anticoagulation strategies in patients undergoing PPCI. Methods. We analyzed records from 2008 through 2013 in the Premier Research Database of patients hospitalized with ST-segment elevation myocardial infarction (STEMI) undergoing PPCI. Patients were categorized into one of four anticoagulation strategies: bivalirudin alone, bivalirudin plus glycoprotein IIb/IIIa inhibitors (GPI), unfractionated or low-molecular-weight heparin alone or heparin plus GPI. In-hospital clinical outcomes were compared between treatment groups after propensity score matching. Results. Among 114,134 eligible STEMI patients, heparin alone was the least frequent anticoagulation strategy, used in 14.4% to 18.1% of cases per year. Bivalirudin alone nearly tripled during the study period, from 12.7% to 37.8% and surpassed that of heparin plus GPI by 2013. Bivalirudin alone performed better than heparin alone for mortality (4.7% vs 5.3%, p = 0.010), clinically apparent bleeding (5.7% vs 6.7%, p < 0.001), transfusion rates (4.1% vs 4.8%, p = 0.003) and mean length of stay (4.1 vs 4.2 days, p < 0.001). The in-hospital death rate was lower with heparin plus GPI than with heparin alone (4.9% vs 5.9%, p < 0.001), but clinically apparent bleeding was higher in heparin plus GPI than in heparin alone (9.4% vs 7.1%, p < 0.001). Conclusion: In patients hospitalized for STEMI undergoing PPCI, heparin alone is not commonly used and is inferior to bivalirudin for mortality, bleeding and length of stay outcomes. Heparin is also inferior to heparin plus GPI for ischemic protection but associated with less bleeding.