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Biomedical subjects

R M Rose

Publications and source records attributed to R M Rose.

At least 163 records · Page 9Linked to original sources
PubMed1976

Sleep during transcendental meditation.

Five experienced practitioners of transcendental meditation spent appreciable parts of meditation sesions in sleep stages 2, 3, and 4. Time spent in each sleep stage varied both between sessions for a given subject and between subjects. In addition, we compare electroencephalogram records made during meditation with those made during naps taken at the same time of day. The range of states observed during meditation does not support the view that meditation produces a single, unique state of consciousness.

Consciousness↗
PubMed1976

Structure and function of the human patella: the role of cancellous bone.

Total joint and other prosthesis often require the removal and replacement of considerable quantities of cancellous bone, and often are anchored in place by grouting into cancellous bone. Thus, a possible source of failure or loosening of many types of prostheses may be rooted in the lack of understanding of the structure, properties, and function of this material. In addition, as we have pointed out before, cancellous bone may play an important biomechanical role in the etiology of joint degeneration. With these considerations in mind, the architecture of the cancellous bone in the human patella was studied by serial sectioning and microradiography, using an improved technique developed in our laboratory. Volumes of cancellous bone with apparently different functional roles were identified. Stereological techniques were used to quantify the structural characteristics and geometrical relationships throughout the patella. These results led to a structural model for the cancellous bone of the patella, and a comprehensive picture of the internal architecture. The distribution of mechanical compliance and yield stress was also measured, as a function of location and orientation, by a specially constructed microcompression testing machine. The measurements reflected the distribution of trabecular architecture, and both the properties and architecture reflected the gross biomechanical function of the patella. Furthermore, a true structure-function relationship was derived. Patellar contact area studies were performed on fresh cadavers and mapped for various angles of flexion. The variation in contact areas and the spatial variations in stiffness are discussed relative to the biomechanics and clinical aspects of the patella.

Biomechanical Phenomena↗
PubMed1976

Analysis of burst activity of the buccal ganglion of Aplysia depilans.

1. Certain nonlinear properties of molluscan neurones suggest that network activity could be described in relation to nonlinear relaxation oscillators. 2. A specific example is fitted by the Van der Pol equation with an exponentially decaying damping coefficient, and changes in the associated energy and sensitivity are considered. 3. More precise details of the interaction pattern determined by analysis of a single cycle of burst activity, and it is shown that there are two states of activity, depending on the balance of presumed inhibitory components. 4. Previous results are discussed in relation to an overall decaying oscillation. 5. Changes in subcomponents of a cycle are described for decaying sequences and the constancy of synaptic interaction is demonstrated. The results are briefly discussed in relation to catastrophe theory and learning.

Action Potentials↗
PubMed1975

Plasma cortisol and growth hormone responses to intravenous characterization.

Plasma cortisol and growth hormone (HGH) responses to venous catheterization were studied in 29 volunteer subjects. Repeat characterizations were performed in 18 individuals. Mean plasma cortisol levels were significantly elevated during the first hour of the initial catheterization experience. Morning and afternoon levels of cortisol were not distinguishable during the first catheterization, but PM levels were significantly lower than AM levels during the second catheterization experience. Growth hormone responses were much more variable than cortisol and were distributed logarithmically. Growth hormone responses tended to parallel cortisol responses during the first catheterization experience. Individuals who listed more symptoms in response to venipuncture and catheterization after finishing their first catheterization had significantly higher cortisol and growth hormone levels during this experience. These data suggest a definite endocrine adaptation to catheterization by the second or third hour of the experience.

Adolescent↗
PubMed1975

"Stiction-friction" of total hip prostheses and its relationship to loosening.

The static friction, or "stiction-friction", in McKee-Farrar and Charnley-Müller prostheses in a hip joint simulator was compared with dynamic friction determined while the prostheses were oscillated. Under physiological conditions stiction-friction differed little from dynamic friction in both metal-on-metal and metal-on-plastic prostheses, and was affected very little by the lubricant as long as some fluid was present. Stiction-friction increased significantly only after relatively long stationary periods and high loads. However, the frictional forces generated in total hip-replacement prostheses were at least forty times higher than those generated in normal joints and may well be enough to cause late loosening of acetabular components by fatigue failure.

Acetabulum↗