Baroreceptor sensitivity after Valsalva maneuver in women with chronic obstructive pulmonary disease.

PURPOSE: Reduced baroreceptor sensitivity (BRS) results in changes in autonomic modulation. Patients with chronic obstructive pulmonary disease (COPD) may have altered BRS. Therefore, we compared BRS between COPD patients and normal controls. METHODS: We compared 14 COPD patients [mean (±SD) age, 62 ± 8 years] to 14 healthy controls [mean (±SD) age, 59 ± 6 years] for the loss of BRS. All patients received ß(2)-agonist therapy but were free from any other type of medication that would interfere with autonomic responses, all controls were free from cardiopulmonary disease, and none was taking medications. All participants were female, post-menopausal, had no known cardiac disease and were ex-smokers. Reduced baroreceptor sensitivity was determined using the slope of the magnitude of R-R widening over the increase in systolic blood pressure following Valsalva maneuver. RESULTS: The mean BRS in controls versus COPD patients showed a mean value of 6.15 ± 2.26 versus 1.91 ± 2.92 ms/mmHg (p < 0.001). CONCLUSIONS: These findings are consistent with other abnormalities of autonomic disruption as previously reported, and demonstrate a severe blunting of the baroreceptor response in individuals with COPD. The cause of this altered BRS response in COPD is not fully clear, we postulate that air trapping with persistent elevation of intrathoracic pressure may lead to a subsequent blunting of the sensitivity of the baroreceptors.

Prostatitis-like symptoms: one year later.

OBJECTIVES: To re-survey (after 1 year) men identified in 1999 as having perineal and/or ejaculatory pain/discomfort severe enough to suggest a clinical diagnosis of chronic prostatitis (using the National Institutes of Health-Chronic Prostatitis Symptom Index, NIH-CPSI), and to compare them with an age-matched population of men who had no prostatitis-like symptoms in the initial survey, to determine the effect of time on specific symptoms associated with the diagnosis of chronic prostatitis. SUBJECTS AND METHODS: A comprehensive questionnaire incorporating the pain and voiding domains of the NIH-CPSI, and data on demographics, medical history, socio-economic status, health-seeking behaviour and a quality of life assessment, was sent to 67 men who had reported prostatitis-like symptoms in the 1999 survey, and to 202 age-matched controls (1 : 3) who reported no prostatitis-like symptoms in the same survey. RESULTS: Forty men (60%) with previous prostatitis-like symptoms, i.e. a mean (sd) 1999 NIH-CPSI pain score of 8.8 (0.4), and 119 (59%) of the control population completed and returned the survey. There was no difference in the 1999 demographics (P = 0.82) or NIH-CPSI pain score (P = 0.49) between patients who returned the recent questionnaire and those who could not be located or declined to complete the survey. Fifteen men (38%) identified with prostatitis in 1999 did not report similar symptoms in 2000. The initial mean NIH-CPSI pain score (0-21) for the men who had resolution of their prostatitis-like symptoms was 7.5 (0.6); 1 year later it was 0.73 (0.3). Their mean age was 51.1 (3.9) years and mean duration of symptoms 1.1 (0.3) years. Those with persistent symptoms had an initial NIH-CPSI pain score of 9.6 (0.5); 1 year later it was 8.68 (0.4), at mean age of 51.4 (2.5) years and duration of symptoms 2.2 (0.3) years. Four men (3%) in the control group who had no symptoms in 1999 reported prostatitis-like symptoms in 2000; these men had a mean age of 52.5 (5.9) and NIH-CPSI pain score of 7.0 (0.9). CONCLUSION: About a third of men reporting prostatitis-like symptoms in the general population had resolution of their symptoms (usually those with a shorter duration and less severe symptoms) 1 year later. The severity of symptoms of men with persistent chronic prostatitis remained relatively unchanged over the year.

Acetylsalicylic acid and autonomic modulation.

Loss of autonomic balance characterized by increased sympathetic activity and decreased vagal activity has been implicated as a major cardiovascular risk factor. Aspirin's cardioprotective abilities involve a multitude of physiologic processes. However, the effects of aspirin on cardiac autonomic activity are unknown. In a double-blind crossover study, 22 subjects randomly received either aspirin or placebo in the amounts of 325 mg with each meal (three times per day) over a 2.5-day period. The total amount of aspirin ingested was 2,275 mg, which resulted in plasma levels of 3.3 mg/dl. At the conclusion of each treatment, subjects were evaluated for autonomic physiology activity using standard autonomic tests. Power spectral analyses of the electrocardiograms were used to delineate autonomic function. A 2 x 4 repeated measures analysis of variance revealed significant and favorable changes in autonomic activity after the use of aspirin. Specifically, at rest high-frequency (HF) power was significantly higher (mean, 1,090 + 1,463.5 msec2) compared with the placebo (mean, 692 742 msec2) (p <0.05). Low-frequency (LF) power was significantly reduced (mean, 963 745 msec2) after aspirin compared with placebo (mean, 1,100 906 msec2). After the aspirin treatment, a significantly lower LF-to-HF power ratio (mean, 1.7 2 msec2) was noted at rest when compared with the placebo (mean, 2.5 2.7 msec2) (p <0.05). Similar significant trends were seen during the sustained isometric contraction after aspirin therapy for HF power (mean 210 2.15 msec2) compared with placebo (mean, 213 184 msec2) (p <0.05). Accordingly, the LF-to-HF power ratio was lower as well when compared to placebo treatment (mean, 2.3 3.5 msec2) (mean, 5.3 8.4 msec2) (p <0.05). No differences were found in breathing rates for hemodynamic variables between any of the protocols. The significant reduction of LF-to-HF ratio, a marker of sympathovagal balance, for both protocols appeared to be largely due to a withdrawal of LF modulation and concomitant but lesser increase in HF modulation. Favorable alterations in autonomic outflow through prostaglandin inhibition may be one of the mechanisms by which low therapeutic amounts of aspirin provide prophylactic cardioprotection.

Präder-Willi syndrome fails to alter cardiac autonomic modulation.

Twenty-six healthy subjects with a diagnosis of Präder-Willi syndrome were compared with 26 age-, gender-, and body mass index-matched controls for autonomic modulation and baroreflex sensitivity. Electrocardiograms, beat-to-beat finger blood pressures, and respiration were recorded for several minutes in the following sequence: (1) supine, (2) after transition from supine to standing, (3) sitting, (4) during a Valsalva maneuver, (5) while performing moderate exercise, and (6) during recovery from exercise while seated. All recordings were channeled and stored in a computer; analyses were carried out at a later date. Power spectral analysis (fast-Fourier transform) of heart period variability was used to assess cardiac autonomic modulation. The slope of the regression equation between heart period and blood pressure rise after the Valsalva maneuver was used as an index of baroreflex sensitivity. Analysis of variance failed to reveal significant differences in any of the autonomic and baroreflex sensitivity variables between the two groups. Because breathing patterns entrain autonomic modulation, we verified respiration and found no differences between the two groups. Therefore, findings in the current investigation indicate that cardiac autonomic modulation in patients with Präder-Willi syndrome does not differ from age and body mass index-matched subjects.

Mechanoreceptors and autonomic responses to movement in humans.

Mechanoreceptor contribution to efferent autonomic outflow is incompletely understood. To determine the effects of mechanoreceptor stimulation on autonomic reflexes, we compared autonomic responses in 34 subjects using a cross-over, counter-balanced design, in which hemodynamic, electromyographic, metabolic, and autonomic data were gathered during rest, passive, and active movement protocols. Because metaboreceptors and ventilatory responses influence autonomic outflow we verified and controlled for these influences during all protocols through comparisons of breath-by-breath gas exchange measurements. Verification of active and passive movements was made via electromyographic recordings of the moving legs. Spectral analysis of R-R variability was used to assess autonomic activity, and low to high frequency ratios were considered representative of sympathovagal balance. A repeated measures analysis of variance revealed significant modulating effects of mechanoreceptor stimulation on sympathovagal balance during passive movement upon efferent autonomic outflow (p < 0.01) independent of central command, chemoreceptor, and metaboreceptor stimulation. Furthermore, breathing frequency and volume were identical for both movement protocols. Therefore, findings in this investigation suggest that modulating influences are being exerted by mechanoreceptor stimulation on autonomic outflow to the heart.

Estrogen replacement, vascular distensibility, and blood pressures in postmenopausal women.

The pathogenesis of blood pressure (BP) rise in aging women remains unexplained, and one of the many incriminating factors may include abnormalities in arteriolar resistance vessels. The aim of this study was to determine the effects of unopposed estrogen on arteriolar distensibility, baroreceptor sensitivity (BRS), BP changes, and rate-pressure product (RPP). We tested the hypotheses that estrogen replacement therapy (ERT) enhances arteriolar distensibility and ameliorates BRS, which leads to decreases in BP and RPP. Postmenopausal women participated in a single-blind crossover study; the participants of this study, after baseline measurements, were randomly assigned to receive estrogen (ERT) or a drug-free treatment with a 6-wk washout period between treatments. The single-blind design was instituted because subjects become unblinded due to physiological changes (i.e., fluid shifts, weight gain, and secretory changes) associated with estrogen intake. However, investigators and technicians involved in data collection and analyses remained blind. After each treatment, subjects performed identical autonomic tests, during which electrocardiograms, beat-by-beat BPs, and respiration were recorded. The area under the dicrotic notch of the BP wave was used as an index of arteriolar distensibility. The magnitude of the reflex bradycardia after a precipitous rise in BP was used to determine BRS. Power spectral analysis of heart rate variability was used to assess autonomic activity. BPs were recorded from resistance vessels in the finger using a beat-by-beat photoplethysmographic device. RPP, a noninvasive marker of myocardial oxygen consumption, was calculated. Repeated-measures analyses of variance revealed a significantly enhanced arteriolar distensibility and BRS after ERT (P < 0.05). A trend of a lower sympathovagal balance at rest was observed after ERT, however, this trend did not reach statistical significance (P = 0.061) compared with the other treatments. The above autonomic changes produced significantly lower systolic and diastolic BP changes and RPPs (P < 0.05) at rest and during isometric exercise. We conclude that short-term unopposed ERT favorably enhances arteriolar distensibility, BRS, and hemodynamic parameters in postmenopausal women. These findings have clinical implications in the goals for treating cardiovascular risk factors in aging women.

Rehabilitation medicine and alternative therapies: new words, old practices.

"Alternative" medicine is receiving increased interest from the public, the media, government, and academic medical centers. Although currently being defined as encompassing practices outside of the medical mainstream, what are now being called "alternative" therapies have long been used by practitioners of physical medicine and rehabilitation. Recently identified by the National Institutes of Health as a legitimate area for research, alternative medicine is now receiving new sources of funding. Physical medicine and rehabilitation (PM&R) expertise encompasses many of the therapies and health care issues that are being categorized as alternative. Practitioners and researchers in PM&R should seize the opportunity to provide leadership in this emerging area in American medicine.

In vitro inhibition of struvite crystal growth by acetohydroxamic acid.

Struvite (MgNH4PO46H2O) crystals were produced by Proteus mirabilis growth in artificial urine, in the presence and absence of the urease inhibitor, acetohydroxamic acid (AHA). In the absence of AHA, struvite crystals assumed an "X-shaped" or dendritic crystal habit due to rapid growth along their 100 axis. When AHA was present, crystal growth, as monitored by phase contrast light microscopy, was greatly slowed, and the crystals assumed an octahedral crystal habit. Scanning electron microscopy revealed that crystals grown in the presence of AHA were pitted on their surface. This pitting was absent in control samples. While most of this inhibition by AHA was due to lowered urease activity, some crystal growth inhibition occurred in struvite produced in the absence of urease activity through NH4OH titration of artificial urine. We conclude that while AHA is primarily a urease inhibitor, it may also disrupt struvite growth and formation directly through interference with the molecular growth processes on crystal surfaces.

Fatal hyperthermia in a quadriplegic man. Possible evidence for a peripheral action of haloperidol in neuroleptic malignant syndrome.

A patient with a cervical cord transection isolating his hypothalamic thermoregulatory centers from peripheral effectors suffered a fatal hyperthermic episode after receiving haloperidol. This suggests that neuroleptic malignant syndrome is caused by a peripheral, not central, effect of haloperidol.

Effect of fever on menopausal hot flashes.

Some women report that they have fewer hot flashes when they have a fever. This is the first case of physiological monitoring of hot flashes during fever in a subject with a well documented pattern of frequent hot flashes when afebrile. During fever, there were fewer hot flashes than during afebrile periods, and these hot flashes also tended to be less intense. For most of the period of reduced hot flashes, internal (core) temperature was elevated, above 37.5 degrees C. When the fever broke, hot flashes resumed in a pattern similar to that of afebrile periods. Possible explanations for the reduction in hot flashes during a fever include: (1) a hot flash is triggered, but the characteristic physiological changes do not occur due to competing thermoregulatory drives, (2) the febrile core temperature inhibits whatever it is that triggers a hot flash; or (3) some product of the fever process inhibits the hot flash trigger or masks the physiological changes that occur during hot flashes.

The cold face test (diving reflex) in clinical autonomic assessment: methodological considerations and repeatability of responses.

1. Cold stimulus applied to the face causes bradycardia and peripheral vasoconstriction (i.e. the diving reflex), and has been suggested as a test of the autonomic pathways involved. The purpose of this study was to define standard procedures for conducting the test and analysing the responses to the cold face test, to evaluate variability in responses between subjects and within subjects when the same test is repeated, and to examine its usefulness in clinical autonomic assessment. 2. Sixteen (nine female, seven male) healthy adult (21-35 years old) subjects were used. Cold stimulus was applied with gel-filled compresses. Forehead temperature under the compress as an indication of stimulus magnitude, heart rate, blood flow in the finger, toe and calf by venous occlusion plethysmography, and systolic and diastolic blood pressure were monitored. Three protocols were carried out in which the temperature (0, 5, 10, 15 degrees C), placement (whole face, unilateral, forehead) and duration (20, 40, 60, 120 s) of the cold compress application were varied. 3. The data indicate that 0 degrees C compresses applied bilaterally for 40 s produced the maximum bradycardia and peripheral vasoconstriction. No subject found this test to be obnoxious, but a 120 s application was objectionable to some subjects. This cold face test resulted in 22%, 72%, 59% and 44% reductions in heart rate and blood flow to the finger, toe and calf, respectively. There was significant between-subject variability, but good consistency in responses to tests repeated in the same subject on different days, at different times of day and in different seasons.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrastructural study of microbiologic colonization of urinary catheters.

We examined ten urinary catheters, associated with catheter-related urinary tract infections, by scanning and transmission electron microscopy to study the morphology of bacterial adherence. We confirmed that the bacteria associated with catheter-associated urinary tract infections grow in glycocalyx-enclosed microcolonies in a biofilm on the catheter surface. The bacterial populations demonstrated a heterogeneity that was not evident from the culture results, and it was demonstrated that only a small proportion of the microorganisms, including fungi, identified morphologically by scanning or transmission electron microscopy are recovered by routine culture methods. The persistence of the bacterial pathogens in catheter-associated infection, even in the face of antibiotic treatment, may be attributed to their adherent mode of growth in protected biofilms and their production of extensive enveloping anionic glycocalyces.

The differential importance of weight and body image among college men and women.

Among a sample of American college students, body image and the degree of desired weight change were associated with academic self-rankings, with social and psychological well-being, and with the development of eating difficulties. The effects of body image and desired weight change on eating disorders were generally found to be greater for women than for men, and their effects on student self-rankings of academic ability, social, and psychological traits were more pervasive for women than for men. The less attractive a woman perceived herself to be and the more weight she wanted to lose, the greater was her overall sense of academic, social, and psychological impairment. Women who had poor body images and who desired to lose weight were more likely to report eating difficulties.

Thermoregulatory physiology of menopausal hot flashes: a review.

Hot flashes during the climacteric years have long been a frequent clinical complaint, generally considered within the realm of the internist, gynecologist, or endocrinologist. Yet the underlying mechanism of hot flashes remains unknown. Only within the past 10 years has there been significant research on hot flashes as a disturbance of thermoregulation. This paper focuses on thermoregulatory aspects of hot flashes, reviewing current knowledge of the thermoregulatory physiology and endocrinology of hot flashes and discussing future avenues for research. Hot flashes are compared with fever in terms of thermoregulatory changes and speculated mechanisms. Although several substances in the peripheral circulation are found in increased concentrations during hot flashes, none is a trigger for a hot flash. The pattern of hot flash occurrence is striking in its regularity, and the possibility of endogenous rhythmicity is discussed. Recently, investigators have begun to explore a primate model of menopausal hot flashes. These studies are summarized. Finally, the multiple effects of estrogen on various systems of the body and their interrelationships are discussed. An understanding of the mechanism of hot flashes would not only be of importance to women suffering with hot flashes but would further our knowledge of thermoregulatory function and the interactions between thermoregulatory and reproductive systems.

Cardiac stress testing of hemiparetic patients with a supine bicycle ergometer: preliminary study.

Ten hemiparetic subjects underwent functional cardiac stress testing on a supine bicycle ergometer. Their heart rate (HR), blood pressure (BP), and rate pressure product (RPP) were determined at rest and at incremental workloads. Three subjects with no previous history of coronary artery disease (CAD) had positive test results diagnostic or suggestive of CAD. None of the three subjects with a history of myocardial infarction displayed any ECG abnormalities during the exercise. The RPPs obtained during testing were compared to those recorded during various rehabilitation activities. As some difficulties arose in the performance and interpretation of the stress test in patients receiving beta-blocking medication and others with arthritis, spasticity, and orthopedic problems, procedures for handling these problems needed review. The supine bicycle proved to be an appropriate device for cardiac stress testing in a hemiparetic population.

Menopausal hot flashes: thermoregulatory, cardiovascular, and circulating catecholamine and LH changes.

Thermoregulatory, cardiovascular and endocrine changes were simultaneously monitored in 11 post-menopausal women with frequent hot flashes (catecholamine and LH levels were measured in 5 and 6 subjects respectively). Plasma samples were obtained at 1- and 5-min intervals. Hot flashes were accompanied by abrupt increases in plasma epinephrine (about 150%) and concomitant decreases in norepinephrine (about 40%). Increased luteinizing hormone was associated with most hot flashes. A detailed sequence of hot flash-associated changes was established. An aura preceded the onset of the hot flash by several seconds. HR and FBF increased just before the onset of the flash and reached peak levels of 10-20 beats/min and 30-fold respectively. Coincident with vasodilation and sweating, finger temperature increased an average of 3.9 degrees C and esophageal temperature fell 0.2-0.6 degrees C. Flashes of both discrete and prolonged intervals were observed. Sensation was a reliable index of flash occurrence and intensity as measured physiologically. Our observations are consistent with the hypothesis that hot flashes are due to a change in the thermoregulatory set point. Furthermore, the changes in catecholamine levels are consistent with the cardiovascular changes accompanying hot flashes.

Cardiac response to exercise: comparison of 3 ergometers.

In order to establish guidelines for clinical decision making based on modified stress testing of physically handicapped individuals, 6 nonhandicapped volunteers exercised on 3 different ergometers, and their cardiac responses were compared. The ergometers were an upright bicycle, a supine bicycle, and an upright arm crank. The parameters measured were heart rate, rate pressure product, and oxygen consumption. Results showed that myocardial oxygen requirements are greater for upper extremity than for lower extremity exercise; the difference becomes increasingly more significant as exercise intensity increases. Myocardial oxygen requirements for supine exercise are greater than for upright exercise at low exercise intensity but lower at higher exercise intensities. Clinical implications of these findings must be interpreted cautiously as older disabled subjects may have different physiologic responses depending on the nature of their disabilities.