Biomedical subjects

P Gilsdorf

Publications and source records attributed to P Gilsdorf.

3 recordsLinked to original sources

PubMed1991

Thirty-minute continuous sitting force measurements with different support surfaces in the spinal cord injured and able-bodied.

Able-bodied, paraplegic, and quadriplegic subjects sat for 30-minute intervals on various surfaces in a wheelchair with a forceplate mounted on the seat in order to determine factors that could contribute to the formation of decubitus ulcers. All three groups of subjects sat on ROHO and Jay cushions; in addition to sitting on the two cushions, the able-bodied subjects sat on a hard surface. Factors studied were: normal and shear seat forces, the location of the center of mass, and armrest force. The forceplate was under the cushions; therefore, the values reflect average forces over the buttocks and posterior thighs. These factors were compared between disability levels as well as between surface types. Larger, normal, and forward shear forces and a more anterior position of the center of mass were observed with the ROHO cushion. More frequent and larger lateral weight shifts occurred with the Jay cushion. The armrests tended to support from 5 percent of the body weight for quadriplegics to 9 percent for paraplegics. The results suggest that armrests reduce seat forces by carrying some of the body weight.

Adult↗

PubMed1990

Sitting forces and wheelchair mechanics.

The effects of back angle and leg height on sitting forces in a wheelchair were studied, using a force plate mounted on a wheelchair seat. Readings of both normal force (perpendicular to the seat) and shear force were measured while the chair's back angle and footrest height were changed. Pressure under the ischial tuberosities was also measured during the footrest height adjustments. Five normal subjects sat directly on the plate as well as upon ROHO and Jay cushions placed on the force plate. Returning the back to the upright position after a recline caused the normal force (+/- SD) to increase 5.4 +/- 2.5, 9.5 +/- 4.0, and 10.0 +/- 2.3 kg for the hard surface, Jay cushion, and ROHO cushion respectively, while shear at the plate increased to 5.1 +/- 2.2, 11.6 +/- 2.6, and 12.3 +/- 2.7 kg for the hard surface, Jay cushion, and ROHO cushion respectively. Leaning forward (away from the back) caused all the forces to return to measurements close to the starting values. The results suggest that the wheelchair user should momentarily lean forward after a recline to reduce undesired forces. If a cushion with firm thigh support is used, ischial tuberosity pressure can be reduced by lowering the leg height as much as possible, which causes a levering action by lifting the pelvis.

Biomechanical Phenomena↗

PubMed1980

Gallstone dissolution with chenodeoxycholic acid. A clinical study.

Out of 95 patients with radiolucent gallstones who enrolled in a clinical study with chenodeoxycholic acid (CDC) for gallstone dissolution 75 patients with cholecystolithiasis completed 12 months of treatment. As a side effect 31% of patients reported intermittent diarrhea which did not cause cessation of therapy or missing of work. The incidence of biliary colic was markedly decreased during treatment in comparison to the rate in the year before. From more than 20 laboratory values checked before start and every 3 months during therapy only aminotransferases increased up to 3 fold in 20% of patients. gamma-GT elevated in 31% of patients before treatment improved in half of these patients during therapy. Gallstone dissolution defined as 30% or more diminution of the gallstone area on comparable x-rays occurred in 40% of patients. Analysis of factors showed that gallstones above 2 cm in diameter did not dissolve. When the dose of CDC was retrospectively related to body weight a success rate of 68% was found in the group taking more than 13 mg CDC/kg/day. The lithogenic index determined at 6 and 12 months had significantly decreased after 6 months in patients with success. This study demonstrates that medical dissolution of gallstones with chenodeoxycholic acid should be performed in patients with radiolucent stones of less than 2 cm in diameter and with a dose above 13 mg CDC/kg body weight/day. Under these conditions the success rate is above 60% accompanied by minimal side effects.

Adolescent↗