Biomedical subjects

A D'angelo

Publications and source records attributed to A D'angelo.

3 recordsLinked to original sources

PubMed2001

Functional mobility performance in an elderly population with lumbar spinal stenosis.

OBJECTIVES: To compare the functional mobility (FM) of elderly apparently healthy (AH) subjects and patients with lumbar spinal stenosis (LSS) and to evaluate the reliability and validity of the FM tests. DESIGN: Using the test-retest paradigm, FM performance was assessed in AH subjects. A single FM assessment was conducted on a group of LSS subjects. Between-group performance comparisons were made with the AH subjects and the LSS patients. SETTING: Orthopedic clinical practice (LSS subjects) and university laboratory (AH subjects). PARTICIPANTS: Fifty-seven patients seen in an orthopedic clinical practice for LSS and 96 AH subjects who were volunteers identified from among participants of The Lifelong Learning Society at Florida Atlantic University. INTERVENTIONS: Treadmill walk (TW) test (at 53.6 m/min, 1% increase in grade per min) until 70% of the predicted maximum heart rate was achieved or associated pain made participation uncomfortable. Three trials each of a sit-to-stand (SS, rise from chair as quickly as possible without using arms) and a weight-carrying (WC, walk 20 m as quickly as possible for time carrying 10% of the body weight evenly distributed in hand-held weights) test. The AH group repeated all tests on a separate day. MAIN OUTCOME MEASURES: Time to walk treadmill, stand from sitting position, walk 20 meters, and analysis of variance between groups. RESULTS: Significant between-group differences were found for the TW, SS, and WC tests. Test-retest r values of .839 for the TW, .848 for the SS, and .833 for the WC were observed. CONCLUSIONS: The AH group demonstrated greater FM than the LSS group. The performance disparity between groups may suggest context validity, while the AH groups test-retest stability reflects reliability.

Activities of Daily Living↗

PubMed2001

Acid production and base balance in patients on chronic haemodialysis.

Acid generation and elimination processes were compared with total base (bicarbonate plus metabolizable anions) turnover in 18 anuric patients undergoing post-dilutional haemofiltration. The study was conducted during the second haemodialysis session of the week by means of a whole-body base balance technique. The results showed that the mean rates of base loss and base gain during dialysis did not differ (i.e. the dialysis base balance approximated to zero). The concurrent mean rate of intestinal base absorption was 66+/-26 mmol/2 days, as calculated from the whole-body balance of the various inorganic cation and anion differences in a metabolic steady state. This level of intestinal base absorption would be capable of neutralizing the 59+/-21 mmol of H(+) ions/2 days that is contributed by sulphuric acid, which is the most important endogenous acid produced in anuric patients. In spite of the fact that intestinal base supply was adequate to neutralize endogenous acid production completely, our patients presented with pre-dialysis non-carbonic acidosis. The depression of plasma bicarbonate levels could not, however, be explained by increased concentrations of the anion gap and organic acids, which were within normal limits both before and after dialysis. We suggest as an alternative hypothesis that this pre-dialysis acidosis may represent an isotonic dilution acidosis that is induced by the ingestion of base-free tap water in order for plasma tonicity to be protected from the accumulation of impermeant dietary solutes, which takes place during the interdialysis period in anuric patients.

Acid-Base Equilibrium↗

PubMed2000

A superoxide dismutase from the archaeon Sulfolobus solfataricus is an extracellular enzyme and prevents the deactivation by superoxide of cell-bound proteins.

An oxygen-induced iron superoxide dismutase was found in the culture fluid of the thermoacidophilic crenarchaeon Sulfolobus solfataricus during growth on glucose-rich media. This protein was also identified as being associated with the cell-surface, with the amount of the released and cell-bound protein fractions depending on the growth phase of the cells. The steady decrease in cell-associated superoxide dismutase during continued growth correlated with the increase of free superoxide dismutase in the medium. Both enzyme fractions were purified to homogeneity and found to be active with different catalytic efficiency, with the released superoxide dismutase showing a fourfold lower specific activity. Characterization in comparison with the cytosolic superoxide dismutase revealed identical N-terminal sequences, electrophoretic mobility, isoelectric point, and molecular mass for all three differently located enzymes. In order to clarify the physiological role of the cell-associated superoxide dismutase, the prevention of cell-bound protein deactivation by oxyradicals was also investigated. Glucose dehydrogenase, which was chosen as a model enzyme, was demonstrated to be located on the cell surface and to be inactivated by potassium superoxide by in vivo assays. The direct protective effect of superoxide dismutase on glucose dehydrogenase was demonstrated by in vitro assays on the free released enzyme. Similarly, the prevention of deactivation by potassium superoxide was also demonstrated for the integral membrane protein succinate dehydrogenase by intact cell assay. Superoxide dismutase added to cells was shown to moderately reduce the critical damaging peroxidation and hence play a major role in maintaining the integrity of the outer cell envelope components.

2,6-Dichloroindophenol↗