Changes in gait patterns and muscle activity following total hip arthroplasty: a six-month follow-up.

BACKGROUND: Appropriate gait function is an important determinant of the outcome of total hip arthroplasty and relies on appropriate joint motion and muscle activity. The purpose of this study was to test the hypothesis that 6-month postoperative dynamic joint range of motion, time-distance measures and muscle activity in the operated limb in patients undergoing total hip arthroplasty differ from preoperative levels and are more similar to those observed postoperatively in the contralateral limb and in healthy subjects. METHODS: Basic time-distance gait measurements, knee and hip kinematics and electromyographic activity from eight hip muscles were obtained preoperatively and 6 months postoperatively in 52 patients undergoing total hip arthroplasty and in 24 age-matched healthy subjects during treadmill walking. FINDINGS: Postoperative dynamic hip range of motion for the operated limb (confidence interval differences [-3.9°; -2.3°]) and postoperative knee range of motion for both limbs (operated: [-8.4°; -5.6°]; contralateral: [-8.1°; -5.3°]) in patients with total hip arthroplasty were significantly lower than values for the control subjects (P<0.001). Postoperative gait in patients with total hip arthroplasty was more symmetric than preoperative gait. Preoperative and postoperative electromyographic intensities were higher in patients with total hip arthroplasty than values for the control subjects (P<0.001), and patients had different EMG patterns compared to the control group. INTERPRETATION: Pre- and postoperative differences not only in hip but also in knee kinematics emphasize the importance of evaluating the dynamic outcome of total hip arthroplasty by assessing joint motion of all lower extremity joints in both legs.

13C discriminations of Pinus sylvestris vs. Pinus ponderosa at a dry site in Brandenburg (eastern Germany): 100-year growth comparison.

The carbon isotope composition (delta(13)C, per thousand) and discrimination (Delta, per thousand) of old grown North American Pinus ponderosa Dougl. Ex P. et C. Laws. and European Pinus sylvestris L. were determined using trees grown under almost identical growing conditions in a mixed stand in Bralitz, Northeast Germany. Single-tree delta(13)C analyses of tree-ring cellulose of both species were carried out at a yearly resolution for the period 1901-2001 and the results compared with growth (basal area increment). Annual mean delta(13)C values for P. ponderosa ranged from-21.6 per thousand to-25.2 per thousand and for P. sylvestris from-21.4 per thousand to-24.4 per thousand. Accordingly, (13)C discrimination (Delta) showed higher values for P. ponderosa throughout the investigation period. Five characteristic periods of Delta were identified for both the tree species, reflecting positive and negative influences of environmental factors. Good growing conditions such as after-thinning events had a positive effect on Delta, reflecting higher values, while poor conditions like aridity and air pollution had a negative influence, reflecting lower values. The dynamics of Delta were likewise reflected in the growth (basal area increment, BAI). Higher (13)C discrimination values of P. ponderosa led to higher BAIs of P. ponderosa in comparison with P. sylvestris. Correlation function analyses confirmed that P. sylvestris was more dependent on precipitation than P. ponderosa, which showed a closer relationship with temperature. The results confirm that under predominantly dry growing conditions, P. ponderosa showed better growth performance than P. sylvestris, indicating better common intrinsic water-use efficiency and, therefore, higher rates of net photosynthesis at a given transpiration. In view of the prospect of climate change, the results are very significant for assessing both trees' physiological properties and, hence, their potential for coping with future growing conditions.

Identification of regulated genes during permanent focal cerebral ischaemia: characterization of the protein kinase 9b5/MARKL1/MARK4.

Cerebral ischaemia induces transcriptional changes in a number of pathophysiologically important genes. Here we have systematically studied gene expression changes after 90 min and 24 h of permanent focal ischaemia in the mouse by an advanced fragment display technique (restriction-mediated differential display). We identified 56 transcriptionally altered genes, many of which provide novel hints to ischaemic pathophysiology. Particularly interesting were two pro-apoptotic genes (Grim19 and Tdag51), whose role in cerebral ischaemia and neuronal cell death has not been recognized so far. Among the unknown sequences, we identified a gene that was rapidly and transiently up-regulated. The encoded protein displayed high homology to the MARK family of serine-threonine protein kinases and has recently been described as MARKL1/MARK4. Here we demonstrate that this protein is a functional protein kinase with the ability to specifically phosphorylate a cognate peptide substrate for the AMP-kinase family. Upon overexpression in heterologous cells, the functional wild-type protein, but not its kinase-dead mutant, led to decreased cell viability. We conclude that the up-regulation of this kinase during focal ischaemia may represent an interesting new target for pharmacological intervention.