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Biomedical subjects

J E Fernandez

Publications and source records attributed to J E Fernandez.

12 recordsLinked to original sources
PubMed1995

Differentiation of a human rhabdomyosarcoma cell line after antineoplastic drug treatment.

The feasibility of treating solid tumours with differentiation therapy using antineoplastic drugs is currently being investigated, but the emergence of multidrug resistance remains the major limitation to this therapeutic approach. A rhabdomyosarcoma cell line resistant to actinomycin D (RD-DAC) has been used as an in vitro model to investigate, with light and electron microscopy, the degree of differentiation in multidrug-resistant cells. The parental cell line (RD), derived from a human embryonic-type rhabdomyosarcoma, is undifferentiated, with no evidence of specific ultrastructural markers. Examination of resistant cells by transmission electron microscopy revealed myofilaments arranged parallel to the long axis of the cell, which was considered clear evidence of myogenic differentiation. These observations suggest that actinomycin D, the drug of choice in the treatment of rhabdomyosarcoma, induces differentiation in the cell line RD. It is postulated that multidrug resistance can interfere with cellular differentiation.

Actin Cytoskeleton↗
PubMed1995

Psychophysical frequency and sustained exertion at varying wrist postures for a drilling task.

Two laboratory experiments were conducted; first, to utilize the psychophysical approach (method of adjustment) to establish maximum acceptable frequency (MAF) for a sheet metal drilling task and, second, to examine the effect of sustained, static exertion upon objective and subjective measures under similar task conditions. In both experiments, the wrist posture (flexation, ulnar deviation) required by the task was varied. Twelve healthy females served as subjects. Results show that the psychophysically adjusted task frequency was significantly lower when wrist deviation was required, particularly flexion. MAF for one-third (25 degrees) and two-thirds (50 degrees) flexion were 88% and 73%, respectively, of those selected in the neutral posture. Furthermore, these results were supported by trends in grip strength, heart rate, blood pressure, EMG and perceived exertion. Results from the sustained exertion trials revealed that significant increases in physiological parameters occurred during 3-minute sessions and that this trend was exasperated with deviated wrist posture, particularly flexion. Considering results of both experiments, it was concluded that while the neutral wrist posture may be preferred for a drilling operation, task frequency should be reduced for deviated postures when redesign is not feasible and it is further recommended that deviation be limited to one-third maximum flexion (25 degrees) and two-thirds maximum ulnar deviation (30 degrees). It is also suggested that the psychophysical approach may be utilized to establish 'acceptable' parameters for other industrial tasks involving upper extremity stress, particularly in the current absence of more objective biomechanical and/or physiological criteria for reducing the risk of exposure to cumulative trauma disorders.

Adult↗
PubMed1994

Psychophysically acceptable weights for a combination lifting task using bags with handles.

This paper presents a study on a combination lift and lower manual handling task and was designed to simulate the loading of grocery bags into a car trunk. Twelve male subjects performed an externally paced task of lifting grocery bags loaded with weights from 15 cm above the floor and over a wooden sill. There were two different sill heights of 70 cm and 90 cm, and for each of these heights there were two frequencies of 3 and 6 lifts per cycle. The dependent variables were maximum acceptable weight of lift (MAWOL). A unique lifting sequence and a modified version of the psychophysical methodology were used to determine MAWOL. There was a significant difference in the MAWOL across the two sill heights as well as the MAWOL at the two different frequencies. Plastic bags were determined to increase the average load lifted by 27% as compared to paper bags. At normal grocery bag weights, the increased load carrying capacity represents an increase in the safety factor. Not only can the risk of lower back injuries be decreased by using plastic bags with handles but the risk of developing a cumulative trauma disorder could also be decreased.

Adult↗
PubMed1994

Maximum acceptable frequencies for females performing a drilling task in different wrist postures.

This paper presents a study on the effect of wrist posture; flexion, extension, ulnar deviation, and radial deviation on maximum acceptable frequencies (MAF) for a drilling task using a psychophysical approach. Twelve females were selected from a college population to serve as subjects and an adjustable workstation was used to simulate a drilling task. The results revealed that flexion, extension, and radial deviation all had a significant effect on MAF but, ulnar deviation did not. The postures have been ranked in order of possible risk of contributing to CTD injury, with neutral having the lowest rank (lowest risk) and flexion having the highest rank (greatest risk).

Adolescent↗
PubMed1992

Anthropometry of south Indian industrial workmen.

This paper presents the results of an anthropometric survey conducted on South Indian male workers in the electronic industry. The data were collected as part of a project to modify work stations that utilized equipment from other countries. A set of 27 body dimensions were taken from a sample of 128 workmen (aged 18-35 years). The anthropometric measurements are compared with those of Indian men from Central, Western, and Northern parts of India and with those of the American, German, and Japanese men. The results indicate that in general the South Indian man is smaller than Central, Western, and Northern Indian men, as well as smaller than men in America, Germany, Japan, and Africa. This difference needs to be allowed for when considering buying and subsequently using imported equipment for the electronics industry in South India.

Adult↗
PubMed1991

Psychophysical lifting capacity over extended periods.

The effect of time on an individual's lifting capacity over extended periods using a psychophysical approach was studied. Twelve male subjects estimated their lifting capacity in a 25 min period, and then attempted to lift this weight for an 8 h period under varying conditions. For one experimental condition the subjects were allowed to adjust the weight, the final adjusted maximum acceptable weight of lift (MAWOL) averaged 85.4% of the original MAWOL determined in the 25 min session. The subjects also attempted to lift for an 8 h period, without any weight adjustments. All 12 subjects lasted the 8 h at 2 lifts per min, but at a frequency of 8 lifts per min only three subjects completed the eight hour lifting task. This indicates that the psychophysical approach is a valid method to measure lifting capacity across the lower lifting frequency range but overestimates the lifting capacity at the higher frequency range. Slight fluctuations were noted in heart rate and oxygen consumption which were recorded every hour.

Adult↗
PubMed1990

Physiological capacities of individuals with cerebral palsy.

The physical work capacity (PWC) and the physiological response to stimulated tasks of nine ambulatory individuals with cerebral palsy (CP) were studied. Energy demand for each work task was determined by percentage of PWC (%PWC). Results demonstrated significant differences in energy demand attributed to frequency and mode of lift regardless of gender. No significant difference for energy demand, however, was seen for load lifted. The %PWC for several tasks was near or above the accepted limit for an eight-hour workday, suggesting that the subjects were performing close to their physical limits or higher and would possibly experience fatigue before the eight-hour workday ended. The results also indicated that the PWC of subjects in this study was inferior to that of their nondisabled peers.

Arousal↗
PubMed1989

Anthropometry of Korean female industrial workers.

This paper presents the results of an anthropometric survey conducted on Korean female workers in the garment industry. The data was collected as part of a project to modify work stations that utilized equipment from other countries. A set of 23 body dimensions were taken from a sample of 101 workers (aged 18-28 years). The anthropometric measurements are presented and compared with those of the Western and Japanese female. The results indicate that the body dimensions of the Korean female are different from those of both the Western and the Japanese female. The ratio of sitting height to standing height for the Korean female is closer to that of the Western female than it is the Japanese female.

Adult↗
PubMed1988

Morphometric study of right ventricle in 32 cases of tetralogy of Fallot.

The right ventricle was the object of a morphometric study in a total of 32 human hearts with tetralogy of Fallot. Most subjects died in the perinatal period and weighed between 720 and 5,000 g. Nine internal parameters were measured in each right ventricle and substituted into the appropriate stereometric formula to yield volumes for each right ventricular chamber. The data obtained were compared to patterns of normality previously obtained by mathematical analysis. The results can be summarized as follows: 1. The right ventricular wall in the present series was thicker than normal, particularly near the tricuspid valve annulus. 2. Pulmonary valve and pulmonary infundibulum perimeter were below normal. 3. Tricuspid valve perimeter was above normal. 4. Above normal figures were obtained for length and volume of the right ventricular inflow tract. 5. Increased outflow tract length contrasted with below normal figures for outflow tract volume. 6. In a large number of cases (95%) the distance between the crista supraventricularis and the pulmonary sigmoid leaflets was reduced. Characterization of these changes may help to elucidate the embryological origin of tetralogy of Fallot.

Cardiac Volume↗
PubMedDate not supplied

A treatment for carpal tunnel syndrome: evaluation of objective and subjective measures.

This study was designed to assess the efficacy of a proposed new and unique program relative to treatment and troubleshooting for diagnostic causes of carpal tunnel syndrome (CTS). Objective measures of anthropometry, strength, range of motion, muscle activity, and task performance, together with subjective ratings of pain were observed in a group of individuals diagnosed with CTS. These measures were compared to a control population showing no symptoms of CTS prior to undergoing treatment and following completion of the treatment program. Results indicate that individuals with CTS had significantly lower values on some strength, range of motion, and slower task performance than did the control group. Ratings of pain and distress were also significantly higher than the controls, and in the literature the CTS group's values approached levels of chronic pain. Analysis of posttreatment cases revealed statistically significant improvements in several strength measures of up to 25% over pretreatment values. Significant improvement was also shown in several range of motion measures of up to 22%. Finally, a significant reduction of 15% in pain and distress ratings was demonstrated in the posttreatment cases.

Adult↗