Amyloid protein of Gerstmann-Sträussler-Scheinker disease (Indiana kindred) is an 11 kd fragment of prion protein with an N-terminal glycine at codon 58.

Gerstmann-Sträussler-Scheinker (GSS) disease is a familial neurological disorder pathologically characterized by amyloid deposition in the cerebrum and cerebellum. The GSS amyloid is immunoreactive to antisera raised against the hamster prion protein (PrP) 27-30. This is a proteinase K-resistant glycoprotein of 27-30 kd that is derived from an abnormal isoform of a neuronal glycoprotein of 33-35 kd designated PrPSc and is a molecular marker of amyloid fibrils isolated from animals with scrapie and humans with related disorders. We have purified and characterized proteins extracted from amyloid plaque cores isolated from two patients of the Indiana kindred of GSS disease. We found that the major component of GSS amyloid is an 11 kd degradation product of PrP, whose N-terminus corresponds to the glycine residue at position 58 of the amino acid sequence deduced from the human PrP cDNA. In addition, amyloid fractions contained larger PrP fragments with apparently intact N-termini and amyloid P component. These findings suggest that the disease process leads to proteolytic cleavage of PrP, generating an amyloidogenic peptide that polymerizes into insoluble fibrils. The N-terminal cleavage of PrP in GSS disease occurs at a tryptophan-glycine peptide bond identical to that cleaved by proteinase K in vitro to generate PrP 27-30 from hamster PrPSc at codon 90. Since no mutations of the structural PrP gene have been found in the Indiana family of GSS disease, it is conceivable that factors other than the primary structure of PrP play a crucial role in the process of amyloid formation and the development of clinical neurologic dysfunction.     

Differences in the infectivity of Babesia incubated in plasma and serum and the role of glucose in prolonging viability

Babesia rodhaini was less infective to mice after incubation in rat serum than in rat plasma. This was explained by lower levels of glucose in serum than in plasma. Both serum and plasma were found to become metabolically depleted of glucose following prolonged contact with clotted and unclotted blood cells, respectively. When glucose concentrations in depleted samples were restored to those in freshly separated samples, infectivities of parasites were similar. This was shown for both B. rodhaini and B. argentina. Products of blood cell metabolism, produced when separation of plasma or serum was delayed for 24 h, were not shown to have any detrimental effects on the parasites. Average glucose values for plasma from rats and cattle were 153 mg/100 ml and 63 mg/100 ml, respectively, whereas serum and plasma remaining in contact with blood cells contained as little as 2 mg glucose/100 ml. Lactate values were correspondingly low in plasma and high in serum. Fibrinogen and platelets, factors involved in clotting, did not affect infectivity of B. rodhaini or B. argentina. The relevance of these findings to living babesial vaccines in which plasma- and serum-based diluents may be used is discussed.     

Exercise training in childhood-onset systemic lupus erythematosus: a controlled randomized trial

Introduction

Exercise training has emerged as a promising therapeutic strategy to counteract physical dysfunction in adult systemic lupus erythematosus. However, no longitudinal studies have evaluated the effects of an exercise training program in childhood-onset systemic lupus erythematosus (C-SLE) patients. The objective was to evaluate the safety and the efficacy of a supervised aerobic training program in improving the cardiorespiratory capacity in C-SLE patients.

Methods

Nineteen physically inactive C-SLE patients were randomly assigned into two groups: trained (TR, n = 10, supervised moderate-intensity aerobic exercise program) and non-trained (NT, n = 9). Gender-, body mass index (BMI)- and age-matched healthy children were recruited as controls (C, n = 10) for baseline (PRE) measurements only. C-SLE patients were assessed at PRE and after 12 weeks of training (POST). Main measurements included exercise tolerance and cardiorespiratory measurements in response to a maximal exercise (that is, peak VO₂, chronotropic reserve (CR), and the heart rate recovery (ΔHRR) (that is, the difference between HR at peak exercise and at both the first (ΔHRR1) and second (ΔHRR2) minutes of recovery after exercise).

Results

The C-SLE NT patients did not present changes in any of the cardiorespiratory parameters at POST (P > 0.05). In contrast, the exercise training program was effective in promoting significant increases in time-to-exhaustion (P = 0.01; ES = 1.07), peak speed (P = 0.01; ES = 1.08), peak VO₂ (P = 0.04; ES = 0.86), CR (P = 0.06; ES = 0.83), and in ΔHRR1 and ΔHRR2 (P = 0.003; ES = 1.29 and P = 0.0008; ES = 1.36, respectively) in the C-SLE TR when compared with the NT group. Moreover, cardiorespiratory parameters were comparable between C-SLE TR patients and C subjects after the exercise training intervention, as evidenced by the ANOVA analysis (P > 0.05, TR vs. C). SLEDAI-2K scores remained stable throughout the study.

Conclusion

A 3-month aerobic exercise training was safe and capable of ameliorating the cardiorespiratory capacity and the autonomic function in C-SLE patients.

Trial registration

NCT01515163.     

Automated Entire Thrombus Density Measurements for Robust and Comprehensive Thrombus Characterization in Patients with Acute Ischemic Stroke

Background and Purpose

In acute ischemic stroke (AIS) management, CT-based thrombus density has been associated with treatment success. However, currently used thrombus measurements are prone to inter-observer variability and oversimplify the heterogeneous thrombus composition. Our aim was first to introduce an automated method to assess the entire thrombus density and then to compare the measured entire thrombus density with respect to current standard manual measurements.

Materials and Method

In 135 AIS patients, the density distribution of the entire thrombus was determined. Density distributions were described using medians, interquartile ranges (IQR), kurtosis, and skewedness. Differences between the median of entire thrombus measurements and commonly applied manual measurements using 3 regions of interest were determined using linear regression.

Results

Density distributions varied considerably with medians ranging from 20.0 to 62.8 HU and IQRs ranging from 9.3 to 55.8 HU. The average median of the thrombus density distributions (43.5 ± 10.2 HU) was lower than the manual assessment (49.6 ± 8.0 HU) (p<0.05). The difference between manual measurements and median density of entire thrombus decreased with increasing density (r = 0.64; p<0.05), revealing relatively higher manual measurements for low density thrombi such that manual density measurement tend overestimates the real thrombus density.

Conclusions

Automatic measurements of the full thrombus expose a wide variety of thrombi density distribution, which is not grasped with currently used manual measurement. Furthermore, discrimination of low and high density thrombi is improved with the automated method.     

Cloning and expression of kinesins from the thermophilic fungus Thermomyces lanuginosus

The motor domain regions of three novel members of the kinesin superfamily TLKIF1, TLKIFC, and TLBIMC were identified in a thermophilic fungus Thermomyces lanuginosus. Based on sequence similarity, they were classified as members of the known kinesin families Unc104/KIF1, KAR3, and BIMC. TLKIF1 was subsequently expressed in Escherichia coli. The expression level was high, and the protein was mostly soluble, easy to purify, and enzymatically active. TLKIF1 is a monomeric kinesin motor, which in a gliding motility assay displays a robust plus-directed microtubule movement up to 2 microm/s. The discovery of TLKIF1 also demonstrates that a family of kinesin motors not previously found in fungi may in fact be used in this group of organisms.     

Novel dendritic kinesin sorting identified by different process targeting of two related kinesins: KIF21A and KIF21B

Neurons use kinesin and dynein microtubule-dependent motor proteins to transport essential cellular components along axonal and dendritic microtubules. In a search for new kinesin-like proteins, we identified two neuronally enriched mouse kinesins that provide insight into a unique intracellular kinesin targeting mechanism in neurons. KIF21A and KIF21B share colinear amino acid similarity to each other, but not to any previously identified kinesins outside of the motor domain. Each protein also contains a domain of seven WD-40 repeats, which may be involved in binding to cargoes. Despite the amino acid sequence similarity between KIF21A and KIF21B, these proteins localize differently to dendrites and axons. KIF21A protein is localized throughout neurons, while KIF21B protein is highly enriched in dendrites. The plus end-directed motor activity of KIF21B and its enrichment in dendrites indicate that models suggesting that minus end-directed motor activity is sufficient for dendrite specific motor localization are inadequate. We suggest that a novel kinesin sorting mechanism is used by neurons to localize KIF21B protein to dendrites since its mRNA is restricted to the cell body.     

A chimera of a gelatinase inhibitor peptide with streptavidin as a bifunctional tumor targeting reagent

A chimeric protein, consisting of streptavidin fused to a cyclic decapeptide with potent inhibitory activity for matrix metalloproteinases (MMP), has been produced in Escherichia coli and purified. The purified chimera formed a tetramer and showed full biotin-binding ability. The chimera was also capable of both binding to MMP-2 and inhibiting its activity. Thus, both the streptavidin moiety and the decapeptide of the chimera are fully functional. This bifunctional nature of the chimera should facilitate the application of the decapeptide since the streptavidin moiety can be used as a specific conjugation site for almost any materials upon biotinylation.     

Towards a framework for the evolutionary genomics of Kinetoplastids: what kind of data and how much?

The current status of kinetoplastids phylogeny and evolution is discussed in view of the recent progresses on genomics. Some ideas on a potential framework for the evolutionary genomics of kinetoplastids are presented.