Instrumental and Non-Instrumental Evaluation of 4-Meter Walking Speed in Older Individuals

BackgroundManual measurement of 4-meter gait speed by a stopwatch is the gold standard test for functional assessment in older adults. However, the accuracy of this technique may be biased by several factors, including intra- and inter-operator variability. Instrumental techniques of measurement using accelerometers may have a higher accuracy. Studies addressing the concordance between these two techniques are missing. The aim of the present community-based observational study was to compare manual and instrumental measurements of 4-meter gait speed in older individuals and to assess their relationship with other indicators of physical performance.MethodsOne-hundred seventy-two (69 men, 103 women) non-disabled community-dwellers aged ≥65 years were enrolled. They underwent a comprehensive geriatric assessment including physical function by Short Physical Performance Battery (SPPB), hand grip strength, and 6-minute walking test (6MWT). Timed usual walking speed on a 4-meter course was assessed by using both a stopwatch (4-meter manual measurement, 4-MM) and a tri-axial accelerometer (4-meter automatic measurement, 4-MA). Correlations between these performance measures were evaluated separately in men and women by partial correlation coefficients.ResultsIn both genders, 4-MA was associated with 4-MM (men r = 0.62, p<0.001; women r = 0.73, p<0.001), handgrip strength (men r = 0.40, p = 0.005; women r = 0.29, p = 0.001) and 6MWT (men r = 0.50, p = 0.0004; women r = 0.22, p = 0.048). 4-MM was associated with handgrip strength and 6MWT in both men and women. Considering gait speed <0.6 m/s as diagnostic of dismobility syndrome, the two methods of assessment disagreed, with a different categorization of subjects, in 19% of men and 23% of women. The use of accelerometer resulted in 29 (13 M, 16 F) additional diagnoses of dismobility, compared with the 4-MM.ConclusionsIn an older population, the concordance of gait speeds manually or instrumentally assessed is not optimal. The results suggest that manual measures might lead to misclassification of a substantial number of subjects. However, longitudinal studies using standardized and validated procedures aimed at the comparison of different techniques are needed before recommending the use of accelerometers in comprehensive geriatric assessment.     

Rolling circle replication requires single-stranded DNA binding protein to avoid termination and production of double-stranded DNA

In rolling circle replication, a circular template of DNA is replicated as a long single-stranded DNA concatamer that spools off when a strand displacing polymerase traverses the circular template. The current view is that this type of replication can only produce single-stranded DNA, because the only 3′-ends available are the ones being replicated along the circular templates. In contrast to this view, we find that rolling circle replication in vitro generates large amounts of double stranded DNA and that the production of single-stranded DNA terminates after some time. These properties can be suppressed by adding single-stranded DNA-binding proteins to the reaction. We conclude that a model in which the polymerase switches templates to the already produced single-stranded DNA, with an exponential distribution of template switching, can explain the observed data. From this, we also provide an estimate value of the switching rate constant.     

Plexin-D1/Semaphorin 3E pathway may contribute to dysregulation of vascular tone control and defective angiogenesis in systemic sclerosis

IntroductionThe vascular and nervous systems have several anatomic and molecular mechanism similarities. Emerging evidence suggests that proteins involved in transmitting axonal guidance cues, including members of class III semaphorin (Sema3) family, play a critical role in blood vessel guidance during physiological and pathological vascular development. Sema3E is a natural antiangiogenic molecule that causes filopodial retraction in endothelial cells, inhibiting cell adhesion by disrupting integrin-mediated adhesive structures. The aim of the present study was to investigate whether in systemic sclerosis (SSc) Plexin-D1/Sema3E axis could be involved in the dysregulation of vascular tone control and angiogenesis.MethodsSema3E levels were measured by quantitative colorimetric sandwich ELISA in serum samples from 48 SSc patients, 45 subjects with primary Raynaud''s phenomenon (pRP) and 48 age-matched and sex-matched healthy controls. Immunofluorescence staining on skin sections from 14 SSc patients and 12 healthy subjects was performed to evaluate Sema3E and Plexin-D1 expression. Western blotting was used to assess Plexin-D1/Sema3E axis in human SSc and healthy dermal microvascular endothelial cells (SSc-MVECs and H-MVECs, respectively) at basal condition and after stimulation with recombinant human vascular endothelial growth factor (VEGF), SSc and healthy sera. Capillary morphogenesis on Matrigel was performed on H-MVECs treated with healthy, pRP or SSc sera in the presence of Sema3E and Plexin-D1 soluble peptides.ResultsSerum Sema3E levels were significantly higher both in pRP subjects and SSc patients than in controls. In SSc, Sema3E levels were significantly increased in patients with early nailfold videocapillaroscopy (NVC) pattern compared to active/late patterns and pRP, and in patients without digital ulcers versus those with ulcers. In SSc skin, Sema3E expression was strongly increased in the microvascular endothelium. Cultured SSc-MVECs showed higher levels of phosphorylated Plexin-D1 and Sema3E expression than H-MVECs, and stimulation with SSc sera increased phosphorylated Plexin-D1 and Sema3E in H-MVECs. The addition of Sema3E-binding Plexin-D1 soluble peptide significantly attenuated the antiangiogenic effect of SSc sera on H-MVECs.ConclusionsOur findings suggest that Plexin-D1/Sema3E axis is triggered in SSc endothelium and may have a role in the dysregulation of angiogenesis and vascular tone control by inducing neuro-vascular mechanism alterations clinically evident in particular in the early disease phases.     

Integrated archaeobotanical research into vegetation management and land use in El Llano de la Horca (Santorcaz, Madrid, central Spain)

This paper presents an integrated archaeobotanical analysis carried out at the site known as “El Llano de la Horca”, a Bronze and Late Iron Age (3rd–1st century b.c.) Carpetanian settlement in central Spain (3600?±?80 b.p.). Pollen and spore analysis indicates an open landscape dominated by the herb taxa Asteraceae, Chenopodiaceae and Poaceae with an important representation of Glomus. The combination of pollen and charcoal studies also reveals the presence of Pinus sylvestris-nigra, P. pinaster-pinea, Juniperus thurifera, Quercus faginea, Q. ilex and Q. suber as the main trees used. Occurrences of Alnus, Corylus, Fraxinus and Juglans suggest the existence of water courses nearby. The archaeobotanical data is correlated with the geographical setting and archaeological context. The evolution of settlement patterns in central Spain, as well as the economy of other Carpetanian sites, is also considered to evaluate how this territory was managed for its vegetational resources since the Bronze Age (BA). Changes are expected as a consequence of different socio-economic factors at this site, especially when the settlement became an important Carpetanian oppidum. The combined results demonstrate a subsistence system based on cereal agriculture, in which naked wheat was dominant, together with some hulled barley and some erratic occurrences of hulled wheat. Furthermore, livestock breeding and metalwork activities seem to have resulted in a significant loss of woodland in order to clear land for crop fields and cattle grazing to cope with the needs of the growing Carpetanian community.     

Investigation of the synthetic route to pepstatin analogues by SPPS using O‐protected and O‐unprotected statine as building blocks

The synthetic route to pepstatin derivatives by a solid phase peptide synthesis using either O‐protected or O‐unprotected statine as a building block has been investigated. Statine was prepared according to a modified literature procedure, whereas protection of its 3‐hydroxyl moiety using tert‐butyldimethylsilylchloride (TBSCl) provided the novel O‐TBS‐protected statine building block. The O‐tert‐butyldimethylsilyl (TBS)‐protected statine approach provides an improved synthetic strategy for the preparation of statine‐containing peptides as demonstrated by the synthesis of the pepstatin analogue iva‐Val‐Leu‐Sta‐Ala‐Sta. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.