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Biomedical subjects

R M Rose

Publications and source records attributed to R M Rose.

At least 127 records · Page 7Linked to original sources
PubMed1982

Computer enhanced digital angiography.

A new computer image enhancement technique was employed on cardiac images of 10 dogs and 7 patients to demonstrate the feasibility of an on-line automatic delineation of the left ventricular endocardial silhouette with a peripheral venous injection of contrast material while simultaneously reducing the x-ray dosage. This technique employs a very fast analog-to-digital conversion system capable of digitizing on-line video frames. By storing and continuously updating the first 30 video frames and then subtracting each incoming frame from this memory, most of the background is eliminated leaving only the contrast filled ventricle. Using calibrated densitometric measurements, we found that iodine concentrations in the human left ventricle following venous injection of 40 ml Renografin-76 (25 ml/s), peaked at 4.3 +/- 0.3 mg/ml (mean +/- SD) compared to 14.8 +/- 0.8 mg/ml following direct injection of 40 ml at 13 ml/s (p less than 0.001). The computer enhanced venous-injected images had an optical contrast 14 times greater than that of the unenhanced direct left ventriculogram. This increase in optical contrast provided unambiguous subjective definition of the endocardial borders. This technique is applicable to both central and peripheral contrast injection whereby high quality images can be obtained at approximately 98% reduction in radiation (5 mA, 65-85 kV), allowing performance of serial studies.

Angiocardiography↗
PubMed1982

Effect of prolonged walking on concrete on the knees of sheep.

Adult sheep were subjected to prolonged activity on hard surfaces by walking them daily on concrete and housing them on tarmac. Control sheep were walked on compliant wood chip surfaces and pastured. After two and a half years significant changes were seen in both the distal femoral articular cartilage and subchondral trabecular bone of the knee joints of the hard surface walkers. The hexosamine content of the articular cartilage in the hard surface walkers was lower and this decrease was more marked in the weight-bearing than in the non-weight-bearing areas of the knee. The trabecular pattern of the subchondral bone became significantly altered, with a marked change in trabecular structure acting to stiffen the tibio-femoral joint at th expense of the patello-femoral articulation. There was a substantial increase in the contiguity ratio of bone in the tibio-femoral area. The cortical thickness of the subchondral plate was increased in both the tibio-femoral and patello-femoral areas. We concluded that significant changes occur in both cartilage and bone as a result of prolonged walking on hard surfaces.

Animals↗
PubMed1982

Endocrine activity in air traffic controllers at work. I. Characterization of cortisol and growth hormone levels during the day.

This is the first in a series of three reports on repeated endocrine studies in the working environment for a group of 416 air traffic controllers. Twenty-minute integrated concentrations for plasma cortisol and human growth hormone across five-hr work periods are described and compared with a selection of studies of normal males reported in the literature. On average, across three repeated studies, controllers were secreting more cortisol and less growth hormone than the most comparable group of normal males. Cortisol and growth hormone levels were not appreciably related, and both hormones showed a lack of consistency across repeated studies in terms of average level or measures of episodic secretory activity. Small increases in cortisol secretion in response to venipuncture were apparent in some controllers during the morning hours; on the other hand, no growth hormone responses were evident. Neither hormone showed decreased secretion with repeated blood collections. Relationships between hormone secretion and the work environment, which possibly explain the lack of hormone consistency across time, will be examined in the second report.

Adult↗
PubMed1982

Endocrine activity in air traffic controllers at work. II. Biological, psychological and work correlates.

This is the second in a series of three papers describing cortisol and growth hormone secretion in air traffic controllers at work. Comparing controllers' average hormone levels across a large number of biological, psychological and occupational characteristics yielded few replicable differences. Comparing men with themselves across three repeated endocrine studies showed a consistent but modest relationship between increases in workload and increases in cortisol. For a subgroup of men classified as 'responders', who had significant increases in cortisol parallel with workload, significantly higher scores were found for peer ratings of their work competency, self-reported job satisfaction and their perception of freedom at work provided them by their supervisors. The modest relationships between workload and endocrine secretion were interpreted as evidence for adaptation by the controllers to their working environment. Cortisol responsiveness to large increases in workload was interpreted as reflecting high levels of job investment.

Adult↗
PubMed1982

Endocrine activity in air traffic controllers at work. III. Relationship to physical and psychiatric morbidity.

This final report in the series of three examines the relationships between physical health change, psychopathology and work responsiveness to cortisol and growth hormone secretion in air traffic controllers. In contrast to expectations, those who had the lowest rates of mild to moderate physical health change showed a modest tendency to have higher average cortisol. Those men who experienced more psychiatric symptomatology in terms of impulse control problems, alcohol abuse and subjective distress had slightly higher average cortisol values at work. Those men who responded to increased workload with increases in cortisol, possibly reflecting increased job involvement, also had higher average cortisol. Physical health change, levels of psychopathology and cortisol responses to increased workload were statistically independent predictors of average cortisol levels.

Adult↗
PubMed1982

Murine cytomegalovirus pneumonia. Description of a model and investigation of pathogenesis.

Pneumonitis was produced in CD-1 mice by intratracheal instillation of murine cytomegalovirus. Lethal pneumonia occurred after instillation of virus derived from partially purified salivary gland homogenates, whereas virus attenuated by serial passage in cell culture caused mild disease and no mortality, even though both virulent and attenuated strains achieved comparable peak titers in lung homogenates. Virulence was characterized by rapid association of virus with pulmonary macrophages and early spread of virus from macrophages to susceptible parenchymal cells. This resulted in enhanced viral growth and cellular destruction during the first 5 days of infection. Delay in the early growth of murine cytomegalovirus in pulmonary parenchyma may diminish the destructive effects of virus on the lung and prevent mortality.

Animals↗
PubMed1982

Wear of polyethylene in the total hip prosthesis.

Direct in vivo measurement of wear of total hip prostheses by radiography is not possible. However, improved in vitro approaches have been developed that agree with clinical observations in all salient points. Such measurements show that the wear of the polyethylene component depends crucially on the molecular weight distribution (and probably on other structural variables). Combined with clinical retrievals, there is evidence that relatively high wear may occur even in the absence of acrylic debris. Although sufficient knowledge exists to reduce wear of the total hip prosthesis to a negligible level, for the total knee replacement with higher contact stresses, presently, this is not the case.

Equipment Failure↗
PubMed1982

Changes in the bone-cement interface after total hip replacement. An in vivo animal study.

UNLABELLED: In order to study the temporal sequence of radiographic, histological, mechanical, bacteriological, and chemical changes around the femoral component following total hip replacement, a model was created by implanting plastic-on-metal total hip replacements in sheep and walking the animals on a concrete surface beginning six weeks postoperatively. This model demonstrated a decreased torsional rigidity between the prosthesis and the femoral cortex in all sheep. Failure of bonding occurred at the bone-cement interface and appears from our results to be most probably due to alterations in the functional stress of the proximal end of the femur following insertion of the femoral component rather than exothermic polymerization, toxicity of free monomer residue, or infection. CLINICAL RELEVANCE: An understanding of the causes of loosening of cemented metal femoral components in total hip replacement has been thwarted by a lack of specimens at sequential times in the loosening process. Since a patient is not operated on until the prosthetic components are completely loose, such specimens are difficult to obtain clinically. For this reason a model for examining the bone-cement interface, measured by decreased torsional rigidity of the prosthesis relative to the bone, was developed in sheep. Of all the parameters studied, those inherent in the effects (mechanical or vascular, or both) of insertion of the prosthesis itself appeared to be the most likely cause of the change in the mechanical properties of the interface. This suggests that degenerative changes of the bone-cement interface may be inevitable.

Animals↗
PubMed1980

Use of a monthly health review to ascertain illness and injuries.

A Monthly Health Review was developed to monitor symptoms, illnesses and injuries among Air Traffic Controllers. Return rate of the mailed check-list exceeded 90 per cent. Diagnoses were generated from symptom clusters by computer algorithms. Telephone interview by physicians, laboratory analyses for serum pepsinogen I, and analyses of relations between symptom clusters and degree of disability all served to support the validity of the methodology. Such a system can provide inexpensive surveillance of morbidity in suitable populations.

Adult↗
PubMed1979

Life changes. Do people really remember?

The question, "How well do people remember life changes?" was approached in a longitudinal study of nearly 400 healthy men in a responsible profession. Three scales for assessing life changes were administered by questionnaire at two examinations nine months apart. The subjects were asked to report life change events occurring during a specific six-month period--that which immediately preceded the first examination. For all three life change scales there was substantial forgetting over the interval between reports, with a second report yielding total scores 34% to 46% less than those from the first report for the same period. The amount of change over time varied greatly across persons. These findings raise serious questions about the validity of retrospective studies of life change and illness when the period being reported is greater than six months in the past. They do not, however, jeopardize the potential of the method for prospective studies.

Adult↗
PubMed1979

The effects of radiation sterilization on the properties of ultrahigh molecular weight polyethylene.

The effects of radiation sterilization on ultrahigh molecular weight polyethylene were explored by freeze fractures, electron spin resonance, absorption of aqueous media, density measurements, small-angle and wide-angle x-ray scatter, differential scanning calorimetry, infrared and ultraviolet-visible spectrometry, static and dynamic mechanical fatigue measurements, and standard environmental stress cracking measurements. The rate of fluid absorption increased significantly due to the appearance of carbonyl groups. As the fluids were absorbed, density increased and small-angle x-ray scatter (SAXS) intensity diminished slightly, as expected. Small changes in mechanical properties (e.g., tensile properties and dynamic spectrum) were always consistent with the cross-linking which occurs after irradiation; the only significant mechanical deterioration was in the fatigue properties. The nonspherulitic, inhibited crystallinity which characterized this material and which is responsible for its excellent static resistance to environmental stress cracking was not at all changed.

Absorption↗
PubMed1979

Psychoendocrinology of the menstrual cycle: I. Enjoyment of daily activities and moods.

Thirty-three women participated in a study of the relationship between moods and enjoyment of activities during the menstrual cycle. All subjects had normal cycles and were screened for psychological health. None were taking oral contraceptives. Each subject filled out daily the Profile of Mood States (POMS) and the Social--Sexual Activities Log (SAAL). They also completed the Moos Menstrual Distress Questionnaire (MDQ) once a month. The SSAL was developed as part of this research in order to provide a means of assessing subjective enjoyment of daily activities. SSAL items were developed from semistructural individual interviews and assessed behavior across eight different categories. Results suggest that the SSAL is a reliable self-report instrument. Although there were no changes in either moods or enjoyment of activities as a function of cycle phase with either the POMS or the SSAL, scores on the MDQ showed the usual cycle-related differences. These findings raise questions concerning the validity of retrospective methods in general, and of the MDQ in particular, as techniques for assessment of personal distress during the menstrual cycle. Equally important, the results suggest that when changes in psychological states are assessed concurrently during the menstrual cycle, the fluctuations observed in a healthy population are minimal.

Adult↗
PubMed1979

Psychoendocrinology of the menstrual cycle: II. The relationship between enjoyment of activities, moods, and reproductive hormones.

Fourteen women served as subjects in a study of the relationships between emotional states, enjoyment of activities, and reproductive hormones. Each subject was psychologically and physically healthy, had a documented history of normal and regular menstrual cycles, was not taking oral contraceptives, and was involved in an ongoing heterosexual relationship. Each woman participated for at least two complete menstrual cycles. The Profile of Mood States and the Social-Sexual Activities Log were filled out daily; other questionnaires were completed less frequently. Blood was drawn between 3 and 5 times/week and was analyzed, using radioimmunoassay methods, from plasma levels of estradiol, progesterone, and luteinizing hormone. Twenty-seven of the twenty-eight cycles appeared to be normal and ovulatory, according to accepted endocrinological criteria. Results showed that in this sample of healthy women there was no relationship between mood states or enjoyment of activities and phase of the menstrual cycle, and no relationship between these psychological states and absolute levels of the reproductive hormones estradiol and progesterone.

Adult↗