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Biomedical subjects

R M Rose

Publications and source records attributed to R M Rose.

211 records · Page 12Linked to original sources

Consequences of social conflict on plasma testosterone levels in rhesus monkeys.

Four adult male rhesus monkeys formed a new social group with 13 adult females. The male who became dominant [alpha] showed a progressive increase in plasma testosterone. The male who became subordinate to the other three males showed an 80% fall in testosterone from baseline levels. After 7 weeks, this group was introduced to a well-established breeding group, and all four males became subordinate to all members of the breeding group. All four males evidenced a fall in testosterone during the first week after introduction, and within 6 weeks their levels were approximately--80% of pre-introduction values. The alpha male of the breeding group showed a large increase in testosterone [238%] 24 hr after he successfully defended his group and became the dominant animal of the larger, newly-formed group. Thus, plasma testosterone levels appear to be significantly influenced by the outcome of conflict attendant to alterations in status of rhesus monkeys living in social groups.

Aggression↗

Cortisol and growth hormone responses to psychological stress during the menstrual cycle.

Twenty-one healthy women were studied during one menstrual cycle in order to determine whether cortisol and growth hormone responsivity to psychological stress was related to estrogen levels. Blood was drawn approximately three times per week for analysis of estradiol, progesterone, cortisol, and human growth hormone. During either the menstrual or intermenstrual phase, each subject participated in an interview that was designed to be mildly stressful. State and trait anxiety were assessed using the Spielberger State-Trait Anxiety Inventory. Anxiety state was measured prior to and immediately following exposure to the psychological stress; trait anxiety was assessed at the end of the study. Cortisol and growth hormone responses to the psychological stress were not related to menstrual cycle phase. Anxiety levels were also independent of menstrual cycle phase. Subjects who displayed significant cortisol and/or growth hormone responsivity to the interview had significantly higher anxiety levels post stress than did nonresponders, although anxiety level prior to the interview was not different for the two groups.

Adult↗

A longitudinal investigation of the relationships among alcohol consumption, psychosocial factors, and blood pressure.

Although a number of studies have demonstrated a link between alcohol intake and blood pressure, virtually no research has examined this relationship or the relevance of psychosocial variables in this context over time. This study utilized data from 416 subjects in the Air Traffic Controller Health Change Study to track these associations across five examinations over a 3-year period. Following obesity, alcohol consumption was consistently the second-best predictor of blood pressure. Alcohol intake rose among those subjects who developed sustained elevated blood pressure during the course of the study. Further, obesity became less important in predicting blood pressure at higher levels of alcohol intake. Factors predictive of alcohol use were also studied, and the suggestion is made that psychosocial variables may be linked primarily to alcohol use, which in turn combines with obesity to influence blood pressure levels.

Adult↗

Definition of a responder: analysis of behavioral, cardiovascular, and endocrine responses to varied workload in air traffic controllers.

Individual differences in behavioral, cardiovascular, and endocrine responses to varying workload among 381 air traffic controllers were assessed using random regression modeling. Although most men showed significant increases in behavioral arousal associated with increasing planes, there were major individual differences in response in systolic and diastolic blood pressure, heart rate, and cortisol. Approximately 20% to 25% of those studied had large increases in each of these domains, along with a smaller group showing inverse responses in heart rate and cortisol. There was also evidence of a smaller number of enhanced responders within the highest groups, who tended to have more missing values at higher levels of workload. There was convergence in the definition of responders using three statistical strategies: random regression, correlational analyses, and ANOVA. Response in one physiological/behavioral domain was essentially independent of response in another, supporting the conclusion of specificity, rather than a global tendency to respond to increasing work load.

Adult↗

Depression in the workplace: effects on short-term disability.

We analyzed data from two national surveys to estimate the short-term work disability associated with thirty-day major depression. Depressed workers were found to have between 1.5 and 3.2 more short-term work-disability days in a thirty-day period than other workers had, with a salary-equivalent productivity loss averaging between $182 and $395. These workplace costs are nearly as large as the direct costs of successful depression treatment, which suggests that encouraging depressed workers to obtain treatment might be cost-effective for some employers.

Absenteeism↗

New rapid method for the study of Pneumocystis carinii interaction with alveolar macrophages.

Understanding the pathophysiology of Pneumocystis carinii infection has been limited by the availability of methods for precisely measuring the interaction of P. carinii with host cells. Here we describe a new method which allows for the rapid assessment of P. carinii binding to, and internalization by, adherent alveolar macrophages. The method is based on the detection of fluorescein-labelled P. carinii by an automated fluorescence measurement system.

Cells, Cultured↗

The effects of extracellular matrix (ECM) proteins on the attachment of Pneumocystis carinii to lung cell lines in vitro.

Pneumocystis carinii cells labeled with fluorescein isothiocyanate were co-cultured with tissue culture cells. Measurements of attachment was determined by the tissue culture cell fluorescence after washing out the P. carinii organisms. The effects of the extracellular matrix proteins, laminin and fibronectin, on the binding of P. carinii onto the monolayer of cultured cells were investigated for better understanding of organism-cell interactions. The internalization of P. carinii by MRC5 cells was observed.

Animals↗

Indicators of Pneumocystis carinii viability in short-term cell culture.

Growth of P. carinii in culture has been difficult to document in the absence of reliable methods for distinguishing live from dead organisms. We studied three markers of cell function in P. carinii during the course of short-term cell culture, and correlated these with the number of P. carinii present in culture supernatants. The markers were glucan synthase activity, esterase activity and cell membrane integrity. The last two were assessed by double staining with fluorescein diacetate and propidium iodide followed by analysis of fluorescence using flow cytometry. The rise in P. carinii number after 5 to 7 days in culture was associated with increased glucan synthase activity. Flow cytometry analysis of day-6 P. carinii cultures confirmed that over 80% of the organisms catalyzed the conversion of fluorescein diacetate to fluorescein and excluded propidium iodide. The demonstration of three indices of metabolic activity in an expanding P. carinii population has confirmed the efficacy of a culture system as a means of sustaining the continued activity, albeit short-lived, of viable P. carinii.

Animals↗

On the origins of high in vivo wear rates in polyethylene components of total joint prostheses.

Scanning electron microscope examination of the polyethylene components of 8 total hip and 16 total knee prostheses which had been implanted 4--96 months revealed that in many cases severe wear may not necessarily be caused by the presence of acrylic cement debris or other abrasives. The craters and cracks observed on severely worn surfaces are associated with fusion defects in the plastic itself. The fusion defects were seen to occur as a result of the low temperature necessary to mold ultrahigh molecular weight polyethylene and are (at least at present) difficult to avoid. As a consequence of the above and variability of molecular weight in this material, relatively wide variations in wear rate should be expected even in the absence of acrylic debris.

Acrylates↗

Effect of repetitive impulsive loading on the knee joints of rabbits.

To simulate the forces from hopping, the right foot of adult rabbits was subjected to 1 1/2 the animal's body weight 40 times a minute for 20-40 minutes per day. During these brief periods of repetitive impulsive loading the legs were held in short-leg splints to eliminate the natural shock-absorbing mechanism associated with ankle dorsiflexion and calve muscle stretching. Under these conditions subchondral bone stiffening occurred and was associated with the earliest metabolic changes of cartilage damage. When bone stiffening returned to normal the effect on the cartilage did not completely disappear, although these effects diminished. The results suggested that subchondral bone stiffening accompanies the earliest metabolic changes in osteoarthrosic chondrocytes and suggests that trabecular microfracture may occur very early in this sequence of events.

Animals↗

Giant cell synovitis associated with failed polyethylene patellar replacements.

Destroyed patellar articular surfaces were replaced with a high molecular weight polyethylene prosthesis in two patients. The patellofemoral articulation of the femur consisted of eburnated bone in one case and degenerative cartilage in the other. Both operations failed within one year because of a giant cell synovitis caused by a high volume (0.2 cc) of fine polyethylene (1-100 mu) wear particles. Ultra high molecular weight polyethylene should not be used as a prosthetic bearing surface to articulate against cortical, cancellous or eburnated bone or against degenerative articular cartilage in a major joint.

Aged↗