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Biomedical subjects

J W Yates

Publications and source records attributed to J W Yates.

64 records · Page 4Linked to original sources
PubMed1973

Leukemia-specific DNA sequences in leukocytes of the leukemic member of identical twins.

The discovery in human leukemic cells of particulate elements encapsulating 70S RNA and RNA-directed DNA polymerase made possible the synthesis of a [(3)H]DNA probe that could detect leukemia-specific sequences in the DNA of normal and leukemic individuals. In an earlier study of a series of unrelated leukemic patients, we established that the nuclear DNA of their leukemic cells contain particle-related sequences that cannot be detected in leukocytes of normal individuals. This result is inconsistent with the virogene concept that demands the inclusion of one complete copy of oncogenic information in the genome of every normal cell. The present study carries this analysis one step further by showing, with two sets of identical twins, that the leukemic member contains particle-related sequences in the DNA of his leukocytes that cannot be detected in the leukocytes of his healthy identical sibling. This finding implies that the additional leukemia-specific information found in the DNA of the leukemic individuals must have been inserted subsequent to fertilization. This outcome argues against the virogene hypothesis or any other etiologic concept that invokes vertical transmission through the germ line of the particle-related information found uniquely in the DNA of leukemic cells.

Adult↗
PubMedDate not supplied

Discriminability of load heaviness: implications for the psychophysical approach to manual lifting.

The main objective of this study was to investigate human ability to discriminate between different levels of load heaviness in manual lifting. Twelve male college students participated in the laboratory experiment. Twenty-eight sequences of five boxes that weighed from 5 to 64 lbs (2.27-29.1 kg) were used. The subjects were asked to arrange boxes in each sequence in order of the perceived (increasing or decreasing) heaviness, i.e., from lightest to the heaviest box, or from heaviest to the lightest box. The subjects were also asked to assign linguistic descriptors of perceived load heaviness to each box in the sequence, and to indicate the confidence levels regarding correctness of the assigned box order and assignment of linguistic values. The independent variables included magnitude of weight and load differential between the successive weights in a sequence. The number of sequential ordering errors, assignment of linguistic variables, and estimated confidence levels were highly dependent on the load differential and weight range. It was concluded that in order to assure reliable results of the psychophysical approach to determining the values of maximum acceptable weight of lift, the adjustment process for male subjects should require using small weights of at least 4 lbs (1.8 kg) to be added or removed from the lifted box. The results of this study also suggest that the error rate in load discriminability can be controlled below the 10% level, if the relative difference in weight between successive boxes lifted is at least 12%. Given the above findings, it is suggested that usefulness of some of the recommendations for setting safe limits for manual lifting tasks, which were reached based on the psychophysical approach and broadly reported in the past, may need to be carefully re-examined. Finally, this study showed that the Weber fraction for load heaviness over the range of lifted weights from 8.6 to 29.1 kg is between 0.03 and 0.04.

Biomechanical Phenomena↗
PubMedDate not supplied

An electromyographic analysis of seated and standing lifting tasks.

The objective of this project was to compare the muscular effort exerted during manual lifting tasks performed in standing versus seated posture. Six male undergraduate and graduate students performed 12 different static and dynamic lifts in both sitting and standing positions. During each effort electromyographic (EMG) data were collected on four muscles groups (low back, upper back, shoulder, and abdominals). Four contractions were designed to elicit maximum muscular effort in the four groups being monitored. The remaining data were then expressed as a percentage of maximum EMG. Each subject performed the following: maximum static lift when sitting; maximum static lift when standing; sitting, static lift with 15.9 kg; standing, static lift with 15.9 kg; dynamic sit-forward lift with 15.9 kg, dynamic stand-forward lift with 15.9 kg, dynamic sit-twist with 15.9 kg, dynamic stand-vertical lift with 15.9 kg. Each of the lifts was performed with a wooden tray with slotted handles. Root mean square (RMS) values of the EMG data were calculated for three second periods. EMG activity in the low back, upper back, and shoulder was greater during sitting lifting than during standing lifting. The sit-twist lift resulted in the highest EMG in the abdominal muscles. Dynamic lifts resulted in more muscle activity than did static lifts. From these data it was concluded that sitting-lifting results in greater stress in the low back, upper back, and shoulders than does lifting while standing.

Adult↗
PubMedDate not supplied

Comorbidity considerations in geriatric oncology research.

Although it is generally acknowledged that comorbidity has a significant impact on treatment selection and outcomes for elderly patients with cancer, an understanding of how comorbid conditions should influence clinical decisions is quite incomplete. This issue remains an important and challenging area of geriatric oncology research. Measures of comorbidity require recognition, documentation, and accurate data extraction. Extensive prospective evaluations and medical chart reviews have the greatest reliability but are costly. Administrative data are convenient and applicable to large populations, but suffer from relatively poor reliability and therefore should be used with caution. Perhaps in the future more refined nosology and better information systems will improve our understanding and ability to use administrative data sets to study comorbidity in the elderly--the eventual goal of such investigation being evidence-based criteria for care of elderly cancer patients.

Age Factors↗