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Biomedical subjects

G Weisman

Publications and source records attributed to G Weisman.

11 recordsLinked to original sources
PubMed1991

Dynamic lifting capacity: the relationship between peak force and weight as an indicator of effort.

Quantification of lifting capacity has become a major component in clinical and occupational evaluations of people with or at risk for low back pain. The ideal test of maximum acceptable lifting would include an index of subject effort. Heart rate response appears to have significant limitations as an indicator of effort. In this study a device that records vertical lifting force measured peak force/weight ratios (PF/W) and differences (PF-W) for individual lifts. Seventeen men without low back pain lifted the device with progressively heavier loads. The PF/W, PF-W, and heart rate responses were compared at half-maximum and maximum effort levels. The PF/Ws were higher, while the PF-Ws and heart rate responses were lower during half-maximum efforts. As an indicator of subject effort, the relationship between peak force and weight may play a key role in isoinertial lifting evaluations.

Adult↗
PubMed1979

Active Ca2+ transport by vesicles reconstituted from Triton X-100-solubilized pigeon erythrocyte membrane.

Pigeon erythrocyte membrane was solubilized partially, but relatively unselectively by Triton X-100. Vesicles were reconstituted from mixtures of Triton-solubilized membrane and lipid (phosphatidylcholine plus phosphatidyl-ethanolamine plus cholesterol) by addition of bovine high-density lipoprotein. This efficiently removed the Triton X-100. Sodium dodecyl sulfate-polyacrylamide gel electropherograms of reconstituted vesicles showed band patterns resembling those of the original membrane. The reconstituted vesicles showed ATP-dependent active accumulation of 45Ca2+. ATP-dependent 45Ca2+ uptake by the reconstituted vesicles resembled the corresponding activity of the original membrane vesicles; in both preparations the Ca2+ uptake rate depended on the square of the Ca2+ concentration and had similar [Ca2+]1/2 values, 0.16 microM and 0.18 microM, respectively.

Adenosine Triphosphate↗
PubMedDate not supplied

Knee injury in skiing. A multifaceted approach.

During the past four ski seasons, all 1,141 ski injuries which occurred in a large northern Vermont ski area were evaluated prospectively. Of these injuries, 21.6% involved knee ligaments and 18.6% involved sprains of the medial collateral ligament. Females sustained a disproportionately high incidence of Grade I medial collateral sprains, but suffered the more severe sprains at a rate similar to that of males. Individuals who were smaller, younger, less experienced, and less skilled sustained a higher incidence of Grade I injuries. Skiers suffering complete tears of the medial collateral ligament were no smaller, younger, or less skilled or experienced than our control population. Medial collateral sprains are produced primarily by external rotation and valgus forces. Two-mode release bindings are insensitive to several loading configurations which could produce knee sprains. Bindings which allow release in roll, shear, and twist at the heel, as well as twist at the toe and forward lean, appear to be necessary to protect the knee.

Athletic Injuries↗
PubMedDate not supplied

Cyclic loading in knee ligament injuries.

The effect of cyclic loading on knee ligaments was studied both in vivo and in vitro. The compliance of the medial collateral ligaments of athletes participating in hockey, basketball, soccer, and downhill skiing was determined by using a specially built machine. Tests were conducted before and after participation in the various sports. Most subjects tested showed an increased compliance after their respective sporting activities. This observation was confirmed in the laboratory by imparting cyclic loading to 10 people under controlled conditions. The in vitro studies were conducted on the medial collateral ligaments of rats. These were tested to determine the effect of cyclic loading on the strength and stiffness of the ligaments. Results show a clear relationship between decreased stiffness or softening and a reduction in strength of the ligament. The amount of softening was related to the cyclic stress in the ligament.

Animals↗
PubMedDate not supplied

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