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Biomedical subjects

T M Cook

Publications and source records attributed to T M Cook.

At least 91 records · Page 5Linked to original sources
PubMed1994

Active surveillance for the control of cumulative trauma disorders: a working model in the newspaper industry.

Health and risk factor surveillance is a critical aspect of an effective ergonomics process. Physical therapists are becoming increasingly involved in many components of the ergonomics process, including health and risk factor surveillance. The purpose of this study was to develop and implement a multistaged active surveillance program for the management and control of cumulative trauma disorders. The surveillance program was established at three newspaper companies consisting of 1,150 employees. This study focused on the first three stages of the multistage surveillance model, which incorporates the use of symptom and job factor questionnaires, specific anatomical surveys, and clinical detection tests. The results of the study indicated that 1) musculoskeletal symptoms in the back, neck, and hands accounted for the majority of reported missed work among the newspaper workers; 2) production workers had a higher prevalence of musculoskeletal symptoms than office workers; and 3) the prevalence of probable carpal tunnel syndrome among the newspaper workers was 1.5%.

Adolescent↗
PubMed1994

Vibration sensibility testing in the workplace. Day-to-day reliability.

Loss of vibration sensibility has been suggested as an early indicator of peripheral compression neuropathy, including carpal tunnel syndrome. Although vibration sensibility has been used frequently to evaluate carpal tunnel syndrome, the day-to-day reliability of vibration measurements in an industrial population measured at the workplace has not been assessed. Vibration sensibility testing was performed at the university ergonomics laboratory on 50 volunteers (100 hands) and at a newspaper company on 50 workers (100 hands). Vibration perception and disappearance thresholds were measured on two occasions separated by 3 to 5 days. Student's t tests indicated no significant differences between the first and second tests or between the two groups. Pearson product-moment correlations for test-retest reliability were lower in the industry group but were relatively high despite the less than optimal testing conditions. Our findings suggest that vibration sensibility measurements are reliable from day to day not only in the laboratory but also in the workplace.

Adult↗
PubMed1993

Effects of seated posture on erector spinae EMG activity during whole body vibration.

The purpose of this study was to evaluate the electromyographic (EMG) response of the erector spinae to whole body vibration in three different unsupported seated postures: neutral upright, forward lean, and posterior lean. Subjects were 11 healthy college-age men. EMG was collected using bipolar surface electrodes placed bilaterally over the erector spinae at the L4 level. A modified chair with attached accelerometer was affixed to an induction type vibrator. Subjects were vibrated vertically at 4.5 Hz and 6.21 m.s-2 RMS. Data were collected in each of the three postures for 30 s pre- and post-vibration and for 2 min during vibration. Mean EMG values were determined for each sampling period and compared using ANOVA. The mean value for anterior lean was significantly larger (p < 0.05) than that for posterior lean and neutral. EMG data analysed by triggered averaging showed a phase-dependent response to the vibratory cycle for the forward leaning and neutral upright postures. The results of this study indicate that the magnitude of the vibration synchronous response of the erector spinae musculature is dependent upon body posture. This response may be an important factor in the onset of muscular fatigue and the increased incidence of back disorders among individuals exposed to whole body vibration.

Adult↗
PubMed1992

An electromyographic analysis of hip abductor muscle activity when subjects are carrying loads in one or both hands.

Forces produced at the hip joint as a result of hip abductor muscle contractions while carrying loads reach several times body weight (BW). Physical therapists often advise patients with hip osteoarthritis in ways to minimize these forces as a means of reducing the pain associated with carrying loads. The purpose of this study was to use surface electromyography (EMG) to quantify the relative demands placed on the hip abductors while carrying loads in one hand or in both hands. Thirty asymptomatic college-aged subjects walked while carrying loads of 10% and 20% of BW unilaterally and loads of 10%, 20%, and 40% of BW bilaterally. Signals from foot switches allowed a computer to average the EMG data over the phase of gait when the foot was in complete contact with the ground. All EMG data were normalized to a percentage of the EMG voltage produced during no-load walking (%EMG). Our prime dependent variable was the %EMG averaged over both hip sides of all subjects' multiple walking trials. Our major analysis involved a multifactorial analysis of variance for repeated measures with method of carry (unilateral or bilateral) and load as the two main independent variables. Results demonstrated that both the amount of the load and the method of load carry made a significant difference in regard to the amount of hip abductor EMG produced. Of particular note was the fact that the bilateral 20% of BW condition produced statistically less %EMG (when averaged over both sides) than did the unilateral 20% of BW condition. Persons with hip disease should be aware that hip joint forces may be reduced by the bilateral method of carrying loads.

Adult↗
PubMed1992

Lumbar support thickness: effect on seated buttock pressure in individuals with and without spinal cord injury.

We compared the effects of different lumbar support thicknesses on seated buttock pressure in individuals with and without spinal cord injury (SCI). Eighteen subjects with SCI (SCI group) and 18 subjects without SCI (control group) were seated on a pressure-sensing transducer incorporated into an adjustable chair. The output was calibrated so that eight pressure intervals (colors) were displayed. The lumbar support thickness was adjusted to 0, 2.5, 5, and 7.5 cm, and the highest and lowest seated buttock pressures were analyzed. External measurements of the hip angle were taken for each lumbar support condition. High reliability of repeated seated test positions was found (intraclass correlation coefficient = .93). The 5- and 7.5-cm-thick lumbar supports caused a decrease in the highest pressure areas in the control group, but no change in the SCI group. The hip angle was increased with each increment in lumbar support thickness in both groups, but the SCI group's hip angle was consistently less than that of the control group for each lumbar support condition. The results of this study suggest that in individuals with chronic paralysis (greater than or equal to 3 years), the use of a wheelchair lumbar support has a negligible effect on seated buttock pressure.

Adult↗
PubMed1991

Electromyographic activity of selected leg musculature in subjects with normal and chronically sprained ankles performing on a BAPS board.

The purpose of this study was to evaluate the magnitude and temporal features of tibialis anterior, peroneus longus, and gastrocnemius muscle activity during exercises performed on a Biomechanical Ankle Platform System (BAPS) board by subjects with normal and chronically sprained ankles. Fourteen participants in each of the two groups rotated the platform in both clockwise and counterclockwise directions at self-selected velocities. Trials were completed with both medium- and large-sized hemispheres under the platform while electromyographic surface recordings were made from the three muscles of interest. Electromyographic values, normalized within individuals as a percentage of maximal voluntary isometric contraction (MVIC), ranged from 20% to 80% of MVIC. An analysis of variance for the average myoelectric signals from all three muscles revealed no differences between the two groups. Effects of direction and hemisphere size were shown for all muscles. The large hemisphere produced significantly greater average activity and a more pronounced effect on the tibialis anterior muscle. The data provide information on the level of muscle activity required for conditions used in this study and may assist the physical therapist with making judgments about the use of this device in rehabilitation programs.

Adult↗
PubMed1991

Characterization of a gyrB mutation responsible for low-level nalidixic acid resistance in Neisseria gonorrhoeae.

Nalidixic acid-resistant derivatives of Neisseria gonorrhoeae WR302 were identified and categorized into two classes on the basis of their susceptibilities to this antimicrobial agent. The MIC of nalidixic acid for the derivative strain MUG116 was fourfold greater than that for its isogenic parental strain WR302 (2 versus 0.5 micrograms/ml, respectively). MUG324 was significantly more resistant to nalidixic acid (greater than 64 micrograms/ml). The MICs of other antimicrobial agents known to interact with either the gyrA or gyrB gene products were determined. Although the nalidixic acid MIC for MUG116 increased, no significant increases in the MICs of other agents that interact with the gyrA gene product were seen. The MICs of all agents that interact with the gyrA gene product were significantly increased for MUG324. The gene that imparts low-level nalidixic acid resistance was cloned from strain MUG116. The DNA sequence of this gene was determined, and by comparing the deduced amino acid sequence with sequences of proteins in data bases, this protein was found to be approximately 70% homologous with the gyrB gene product of Escherichia coli.

Amino Acid Sequence↗
PubMed1990

An electromyographic analysis of the hip abductor muscles during a standing work task.

Research data strongly suggest that osteoarthritis of the hip occurs statistically more often on the right side. A possible contributing factor to this right-sided bias in frequency may be that the articular cartilage on the right hip is subjected to relatively higher muscular-based forces throughout a lifetime. As an initial attempt to study this possibility, this research examined healthy persons to determine the existence of a "dominant" hip similar to that expressed for handedness. Electromyographic (EMG) analysis was used to compare the electrical activity between the right and left hip abductor muscles during a standardized standing work task using 40 right-handed and 40 left-handed healthy subjects. Analysis of the data showed that the hip muscle on the side of the subject's handedness produced higher normalized EMG activity than did the opposite hip; however, the differences were not all statistically significant. The trend of this data set, however, warrants further research into a possible association between hip dominance, asymmetrical muscle use, and the development of hip osteoarthritis.

Adult↗
PubMed1989

Electromyographic analysis of hip abductor musculature in healthy right-handed persons.

The right hip abductor (HA) musculature has been reported to demonstrate stretch weakness attributable to chronic elongation imposed by standing posture common to right-handed healthy individuals. Research has shown side-specific differences in maximal isometric torque-hip abduction angle curves for the HA muscles in a similar population. The purposes of this study were to assess isometric hip abduction torque in a sample of 40 healthy right-handed persons and to compare side differences in the HA muscles' neural drive index across a wide range of hip abduction angles. The neural drive index was defined as the magnitude of the normalized surface electromyographic activity divided by the absolute magnitude of a submaximal (20% of maximal) isometric HA muscle torque. Data were collected while subjects were positioned supine with trunk and pelvis stabilized. Statistical analysis of the data did not support earlier research on right HA muscle stretch-weakness; however, trends in the data suggest the need for further research. We also discuss the functional role of the passive noncontractile elements of the HA musculature.

Adult↗
PubMed1988

Lesion-induced CA1 mossy fibers in the rat represent a neoinnervation.

The developmental pattern of hippocampal mossy fiber (dentate granule cell axon) innervation to the pyramidal cell layer was examined with anterograde transport methods. Injection of 3H-leucine into the dentate gyrus on PN 1 resulted in labeling of the incipient stratum lucidum extending to, but not beyond, the CA3 region on PN 3 and 5. Since destruction of CA3 pyramidal cells on PN 5 results in aberrant mossy fiber innervation to CA1 pyramidal cells (Cook and Crutcher 1985), these results suggest that the presence of mossy fibers in CA1 of the rat represents a neoinnervation (perhaps representing a more primitive pattern of connectivity) and not the persistence of a transient developmental projection.

Animals↗
PubMed1988

Effect of seat angle and lumbar support on seated buttock pressure.

The purpose of this study was to compare the effects of a lumbar support at two seat angles (0 degrees and 10 degrees of posterior tilt) on the area of highest buttock pressure. Twenty able-bodied subjects were seated on a pressure-sensing transducer incorporated into an adjustable chair (ischiobarograph). A video camera on the underside of the transducer detected changes in light levels in direct relation to pressure application. The camera output was processed by a microcomputer system that converted the signal into nine colors, each representing a distinct pressure interval in the range of 0 to more than 500 mm Hg. The microcomputer determined the area of each pressure interval before and after a 10-degree posterior tilt of the seat and lumbar support placement. The results demonstrated high test-retest reliability for each position (r = .95). A significant decrease in the six highest pressure intervals occurred when the lumbar support was used in both the upright and reclined positions (p less than .05). The results of this study have implications for wheelchair-dependent individuals.

Buttocks↗
PubMed1988

Comparison of maximal isometric hip abductor muscle torques between hip sides.

A posturally induced "stretch weakness" of the right hip abductor muscles has been reported in many healthy right-handed persons in the literature. The purpose of this study was to test for differences in the maximal isometric hip abduction torque produced between hip sides across multiple hip abduction angles. The torques were measured on 40 healthy right-handed individuals using a specialized torque-testing table at hip abduction angles of -10, 0, 10, 20, 30, and 40 degrees. Statistical analysis of the results did not demonstrate a specific "weakness" of the right hip abductor muscles at the hip angle used to clinically test them. The results, however, did demonstrate statistically significant differences in the torque-hip angle slopes across hip sides. We hypothesized that these slope differences may result from muscle adaptation to lengths imposed by standing posture. We discuss how manual muscle testing procedures may bias the likelihood of encountering stretch weakness in muscles that are habitually maintained at near-maximal elongation.

Adult↗
PubMed1986

Intrahippocampal injection of kainic acid produces significant pyramidal cell loss in neonatal rats.

Previous reports have indicated that pyramidal cells in the developing rat hippocampal formation are not destroyed by intraventricular or intraperitoneal administration of kainic acid. We examined the neurotoxic properties of kainic acid and ibotenic acid following intrahippocampal injection in neonatal rats and found significant pyramidal cell death following injection of 1.0 microgram kainic acid in 6, 7 and 9-day-old pups. At doses 2.5 or five times this amount, significant pyramidal cell loss was obtained in 5-day-old rats as well. The susceptibility of pyramidal neurons to kainic acid increased as a function of age. The developing hippocampus was considerably more vulnerable to ibotenic acid compared with kainic acid, in contrast to the order of potency reported in adult rats. The increased sensitivity of CA3 pyramidal cells parallels the development of the mossy fiber innervation to the dendrites of these cells supporting the twofold mechanism suggested by Coyle for kainic acid neurotoxicity; that is, a direct cytotoxic action via postsynaptic receptors as well as increased sensitivity due to the presence of excitatory inputs.

Animals↗