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Biomedical subjects

D Rafferty

Publications and source records attributed to D Rafferty.

11 recordsLinked to original sources
PubMed2000

The application of control limits analysis to the myometric assessment of motor performance in neuropathy patients.

Measurement of muscle strength by myometry is used to monitor the natural course and treatment response of motor system diseases, both in individual patients and clinical trials. However, the practical usefulness of myometric data is reliant upon a statistical method for analysing serial strength measurements which distinguishes disease-related changes from random fluctuations in patient performance and operator/device dependent measurement errors. In this study we have applied control limits analysis to this problem. Using hand-held dynamometry, sets of baseline strength measurements were collected on two separate occasions during a period of clinical stability from up to four muscle groups in 22 patients with peripheral neuropathies. From these sets of data, 76 control limits were calculated and then used to describe the inter-measurement variation in muscle strength in individual muscles. The range of control limits was wide, varying from <10% of baseline (in 36% of muscles tested) to >50% (in 4% of muscles tested), with 88% of muscles falling within 30% of baseline. Follow-up data were also collected from all patients, including those undergoing treatment. Control limits analysis is a powerful and simple method for assessing the significance of motor performance changes in individual muscles in patients undergoing serial monitoring and can be easily applied to both single patients and clinical trials.

Adolescent↗
PubMed1997

Relationship between isokinetic muscle strength and exercise capacity in chronic heart failure.

The exercise intolerance and excessive ventilatory response to exercise of chronic heart failure is associated with abnormalities of skeletal muscle function, in particular a reduction in muscle strength. Isometric and isokinetic leg muscle strength were measured in 10 patients with chronic heart failure and 10 age-matched controls. Each subject undertook maximal exercise testing to measure peak oxygen consumption (V(O2)) and the ventilatory response to exercise as measured by the slope of the relation between ventilation and carbon dioxide production (V(E)/V(CO2) slope). Quadriceps strength (mean (S.D.)) was reduced in heart failure as measured by isometric (444.9 (129.6) N vs. 556.0 (136.0); P<0.01) and isokinetic (123.6 (30.2) Nm vs. 146.8 (40.0); P=0.04). Hamstring strength was also reduced as measured by isokinetic testing (53.6 (15.6) Nm vs. 71.1 (28.1); P=0.02). Isokinetic and isometric strengths correlated, but not closely (r=0.52, P<0.001). There were negative correlations between the V(E)/V(CO2) slope, and isokinetic measures: with average torque, r=-0.62, P<0.004; with peak torque, r=-0.64, P=0.002. We have found evidence for reduced muscle function affecting both knee flexors and extensors. This reduction in muscle strength correlates with the ventilatory response to exercise. These observations lend support to the muscle hypothesis of the generation of symptoms in chronic heart failure.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

Exercise dynamics at submaximal workloads in patients with chronic heart failure.

BACKGROUND: The aims of this study were to analyze the relationship between exercise at self-selected work loads and peak exercise performance in patients with chronic heart failure and to analyze possible relationships between gait pattern and exercise performance and ventilatory response to exercise in chronic heart failure. METHODS AND RESULTS: Twelve patients with stable chronic heart failure and 10 age- and build-matched control subjects undertook symptom-limited maximal exercise testing with metabolic gas exchange measurements to determine peak oxygen consumption (VO2) and the slope of the relationship between ventilation and carbon dioxide production (VE/VCO2 slope). Respiratory rate was also determined. Self-selected walking pace and cadence (steps per minute) were determined. Metabolic gas exchange analysis was repeated at matched low-level exercise and at self-selected walking pace. Self-selected exercise was at a lower speed for patients than control subjects (1.28 [0.22] vs 1.43 [0.19] m s-1), representing a similar proportion of peak oxygen consumption (63.6 [19.3]% vs 56.7 [25.4]%). There was a relationship between peak VO2 and VO2 at self-selected workload (r = .55, P < .001) and self-selected walking velocity (r = .58, P < .005). Gait analysis demonstrated that the reduction in self-selected velocity in heart failure patients was due to a reduced cadence (101.5 [8.7] steps/min vs 110.2 [9.1] steps/min, P < .01), not a reduction in stride length. There was a negative relationship between VE/VCO2 slope and self-selected cadence (r = -.68, P < .001) and a negative correlation between respiratory rate and cadence at self-selected workload (r = -.6, P < .005). CONCLUSIONS: Self-selected walking speed is at the same proportion of peak oxygen consumption in patients with heart failure as compared with control subjects, but a lower absolute level. Patients have the same stride length as normal control subjects. Ventilation is increased in patients, but there is no direct relationship between ventilation and gait.

Exercise Test↗
PubMed1993

Intravaginal immunization in sheep using a bioadhesive microsphere antigen delivery system.

An enzymatically cleaved glycoprotein fragment (amino acids 28-328: 40 kDa) from influenza virus haemagglutinin (TOPS) was used to assess an intravaginal antigen delivery system, comprising lysophosphatidylcholine (LPC) and degradable starch microspheres (DSM). Three groups of three sheep received intravaginal immunization with TOPS as follows: group 2, TOPS in solution; group 3, TOPS and DSM/LPC as a powder formulation and group 4, TOPS and LPC in solution. A fourth group, group 1, received intramuscular immunization with TOPS adsorbed to aluminium hydroxide gel (Alugel). Intravaginal immunizations were repeated on two consecutive days. Two weeks later, booster doses of the same formulations were administered on two consecutive days to each group. Group 1 sheep were boosted with a single injection, 2 weeks after the single primary immunization. The serum and vaginal wash IgA and IgG antibody responses were compared among the four groups of sheep at days 15, 30 and 45 after the booster immunizations. At day 45, the serum IgG and the vaginal wash IgA antibody responses induced by TOPS and DSM/LPC (group 3), were significantly greater than the responses induced by intravaginal immunization with TOPS (group 2). However, the highest levels of antibodies in serum and vaginal wash samples were induced by intramuscular immunization with TOPS and Alugel (group 1). Intravaginal immunization with TOPS and LPC (group 4) did not result in the induction of enhanced levels of antibodies in serum or vaginal wash samples.

Administration, Intravaginal↗
PubMed1992

Vaginal immunization of rats with a synthetic peptide from human immunodeficiency virus envelope glycoprotein.

Local secretory immunity in the vagina may confer a degree of protection against heterosexual transmission of human immunodeficiency virus (HIV). Since the vagina has been shown to respond to local immunization, we have undertaken intravaginal immunization of rats with a 20-mer peptide (amino acid residues 102 to 121) of the HIV-1 envelope glycoprotein (gp120). The peptide was administered in combination with an 'absorption enhancer', lysophosphatidyl glycerol (LPG), which has previously been shown to promote the absorption of intravaginally administered peptides, while exerting only mild effects on epithelial membrane integrity. Intravaginal immunization with LPG and the peptide induced serum and vaginal wash IgA and IgG antibody responses which were enhanced in comparison to those after immunization with the peptide alone. Serum antibodies induced by both subcutaneous and intravaginal immunization were able to recognize recombinant HIV-1 gp120. However, the rat antiserum displayed no neutralizing activity against the virus. These results demonstrate that LPG is an effective immunological adjuvant for intravaginally administered peptide antigens. An alternative absorption enhancer, bestatin (BES), was not effective as an immunological adjuvant when administered intravaginally and blocked the adjuvant activity of LPG when BES and LPG were used in combination.

AIDS Vaccines↗