Biomedical subjects

Robert Price

Publications and source records attributed to Robert Price.

41 records · Page 3Linked to original sources

PubMed2002

Isolated gastrocnemius tightness.

BACKGROUND: Contracture of the gastrocnemius-soleus complex has well-documented deleterious effects on lower-limb function in spastic or neurologically impaired individuals. There is scarce literature, however, on the existence of isolated gastrocnemius contracture or its impact in otherwise normal patients. We hypothesized that an inability to dorsiflex the ankle due to equinus contracture leads to increased pain in the forefoot and/or midfoot and therefore a population with such pain will have less maximum ankle dorsiflexion than controls. We further postulated that the difference would be present whether the knee was extended or flexed. METHODS: This investigation was a prospective comparison of maximal ankle dorsiflexion, as a proxy for gastrocnemius tension, in response to a load applied to the undersurface of the foot in two healthy age, weight, and sex-matched groups. The patient group comprised thirty-four consecutive patients with a diagnosis of metatarsalgia or related midfoot and/or forefoot symptoms. The control group consisted of thirty-four individuals without foot or ankle symptoms. The participants were clinically examined for gastrocnemius and soleus contracture and were subsequently assessed for tightness with use of a specially designed electrogoniometer. Measurements were made both with the knee extended (the gastrocnemius under tension) and with the knee flexed (the gastrocnemius relaxed). RESULTS: With the knee fully extended, the average maximal ankle dorsiflexion was 4.5 degrees in the patient group and 13.1 degrees in the control group (p < 0.001). With the knee flexed 90 degrees, the average was 17.9 degrees in the patient group and 22.3 degrees in the control population (p = 0.09). When gastrocnemius contracture was defined as dorsiflexion of < or = 5 degrees during knee extension, it was identified in 65% of the patients compared with 24% of the control population. However, when gastrocnemius contracture was defined as dorsiflexion of < or = 10 degrees, it was present in 88% and 44%, respectively. When gastrocnemius-soleus contracture was defined as dorsiflexion of < or = 10 degrees with the knee in 90 degrees of flexion, it was identified in 29% of the patient group and 15% of the control group. CONCLUSIONS: On the average, patients with forefoot and/or midfoot symptoms had less maximum ankle dorsiflexion with the knee extended than did a control population without foot or ankle symptoms. When the knee was flexed 90 degrees to relax the gastrocnemius, this difference was no longer present. CLINICAL RELEVANCE: These findings support the existence of isolated gastrocnemius contracture in the development of forefoot and/or midfoot pathology in otherwise healthy people. These data may have implications for preventative and therapeutic care of patients with chronic foot problems.

Adult↗

PubMedDate not supplied

Continued investigation into the influence of loaded dose on the performance of dry powder inhalers: surface smoothing effects.

The aerosolization of salbutamol sulfate, measured as fine particle dose (FPD LD) and fine particle fraction (FPF LD) (<6.4 microm mass median aerodynamic diameter), from two sieved (63-90 microm) lactose monohydrate carriers, one as supplied, one smoothed by controlled surface dissolution, was studied. In general, no significant variation in FPD LD was observed at drug loadings between 10 and 63.5 microg and 10 and 135 microg for the surface dissolved and as supplied lactose monohydrates, respectively. Increasing the drug load above these levels resulted in linear increases in FPD LD with increasing drug load with the surface dissolved lactose monohydrate exhibiting higher FPD LD and FPF LD. This suggests that, at lower drug loadings, areas of the carrier exhibiting higher adhesion, so-called active sites, were being preferentially occupied and filled. Since there was no evidence of drug agglomeration using scanning electron microscopy, the observations suggest that the number and range of such higher energy "active sites" can be reduced by modifying the surface roughness, that is, energies, of the carrier.

Administration, Inhalation↗

PubMedDate not supplied

A novel apparatus for the determination of solubility in pressurized metered dose inhalers.

The accurate solubility of salbutamol sulfate, budesonide, and formoterol fumarate dihydrate in hydrofluoroalkane propellant 134a at 25 degrees C for 24 h, are reported. The authors describe a novel reusable in-line pressurized solubility apparatus containing an integral filter holder and a continuous decrimpable valve for the determination of drug/excipients solubility in pressurized metered dose inhalers. The solubility was determined by high-performance liquid chromatography. Solubility of salbutamol sulfate was determined as being below the detection limits while budesonide and formoterol fumarate dihydrate solubility were 23.136 +/- 2.951 microg x g(-1) and 0.776 +/- 1.023 microg x g(-1), respectively (n = 3). This novel solubility apparatus offers an improved ease of use and potential higher analytical throughput.

Administration, Inhalation↗

PubMedDate not supplied

Pushrim biomechanics and injury prevention in spinal cord injury: recommendations based on CULP-SCI investigations.

Over 50 percent of manual wheelchair users with spinal cord injury (SCI) are likely to develop upper-limb pain and injury. The majority of studies related to pain have implicated wheelchair propulsion as a cause. This paper draws from a large multisite trial and a long-standing research program to make specific recommendations related to wheelchair propulsion that may decrease the risk of upper-limb injury. The studies include over 60 subjects over 1 yr after a traumatic SCI below the second thoracic level. Specific aspects of the propulsive stroke that may relate to injury include cadence, magnitude of force, and the pattern of the hand during the nonpropulsive part of the stroke. Lower peak forces, slower cadence, and a circular propulsive stroke in which the hand falls below the pushrim during recovery may help prevent injury. In addition, wheelchair users should use the lightest weight adjustable wheelchair possible. Future work should include interventional trials and larger studies that allow for more complex statistical models that can further detail the relationship between wheelchair propulsion, user characteristics, and upper-limb injuries.

Adult↗

PubMedDate not supplied

Assessment of an electronic goniometer designed to measure equinus contracture.

To achieve more objective and repeatable measurements of equinus contracture, we developed the equinometer, a device that allows the measurement of ankle range of motion under controlled torque conditions. This study assessed its accuracy across different subjects and examiners. Two examiners used the equinometer to measure the angle of ankle dorsiflexion at 15 N x m torque on five subjects. Accounting for variation in measurements because of subjects, examiners, and placement of device, we used linear mixed-effects models. Accounting for the variation because of subject, different placements of the equinometer within each subject and the adjustment for the effects of examiner and trial sequence, the standard deviation was 0.94 degrees, 95% confidence interval (0.79 degrees, 1.13 degrees). An upper standard deviation of 1.36 degrees is felt to be acceptable for clinical investigation.

Ankle Joint↗