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Biomedical subjects

C D Harris

Publications and source records attributed to C D Harris.

9 recordsLinked to original sources
PubMed1996

Patient satisfaction with collaborative practice.

OBJECTIVE: To gather information on women's perceptions of the services delivered in collaborative obstetrics and gynecology practices and to determine whether patients perceive a difference in the delivery of services in a variety of practice settings. METHODS: A cross-sectional patient satisfaction survey was developed by the Collaborative Practice Advisory Group of ACOG. Ten collaborative practices were selected to participate: five in private offices, two in clinics, two in health maintenance organizations, and one in the military. Between April 15 and May 15, 1994, 3257 completed surveys were obtained for analysis. RESULTS: Between 71% and 92% of women, depending upon the practice setting, agreed with statements regarding the possible benefits from being cared for in a collaborative practice. The majority (75-92%) expected services provided in a collaborative practice to differ from those provided in a noncollaborative practice. Women making their first visit to a collaborative practice expected quicker appointments, more time with the provider, more health information, and more specific diet information than did women who had previously been seen in such a practice. There were minimal differences in comfort levels when discussing issues of sexuality and physical and sexual abuse in either public or private settings with physicians or non-physicians. CONCLUSIONS: Patients in this survey were accepting of the concept of collaborative practice and felt that it offered quicker appointments, more time with the provider, more health information, and more specific diet information than did physician-only practices.

Adult↗
PubMed1995

Comparison of RigiScan and sleep laboratory nocturnal penile tumescence in the diagnosis of organic impotence.

PURPOSE: We evaluated the relative use of RigiScan measurement of radial rigidity compared to sleep laboratory measurement of axial rigidity and trained observer determination of erectile function in the diagnosis of organic impotence. MATERIALS AND METHODS: A total of 28 patients underwent simultaneous 2-night formal sleep laboratory nocturnal penile tumescence and RigiScan monitoring. Standard normal values for radial rigidity and axial rigidity were tested for accuracy in predicting normal nocturnal penile tumescence compared to trained observer determination of the adequacy of an erection for penetration. RESULTS: RigiScan tip measurements correlated poorly with buckling pressure, while base measurements strongly correlated (p = 0.0005). Observer determination of a functional erection was strongly associated with tip (p = 0.002), base (p = 0.0005) and buckling pressure measurements (p = 0.0005). Using observer determination as the gold standard receiver operating curves were generated to select RigiScan base and buckling pressure measurements that predicted functional erections with the highest sensitivity and specificity. CONCLUSIONS: RigiScan is a useful tool for measuring nocturnal penile tumescence. However, base measurements are more accurate than tip measurements for evaluating erectile function. The currently accepted level of rigidity used to define a normal erection (70% or greater) overestimates organic erectile dysfunction.

Adult↗
PubMed1994

Acute effects of transdermal nicotine on sleep architecture, snoring, and sleep-disordered breathing in nonsmokers.

Previous research has suggested that nicotine may be therapeutically useful in the treatment of sleep-disordered breathing. The development of transdermal nicotine delivery systems has allowed us to test the overnight effectiveness of nicotine. Twenty nonsmoking subjects (10 men, 10 women) were recruited on the basis of a history of habitual snoring that was confirmed by overnight laboratory monitoring. Subjects were then randomized (double-blind crossover design) to receive either placebo or an active patch that delivers 11 mg of nicotine over a 24-h period. Patches were applied at 6 P.M. and removed at 6 A.M. the following morning, at which time venous blood was obtained for determination of serum nicotine concentrations. Polysomnography was performed using standard techniques to assess sleep architecture and sleep-disordered breathing. Snoring was monitored with a sound-level meter and quantitatively analyzed to determine the snoring index (SI) (number of snores per hour of sleep) and mean and maximum snoring intensities. The age of the subjects was 46.9 +/- 11.4 yr (mean +/- SD) and their mean body mass index (BMI) 33.3 +/- 4.6 kg/m2. A mean nicotine level was nondetectable with placebo and 7.8 +/- 2.3 ng/ml with wearing of an active patch. Nicotine decreased total sleep time (TST) by 33 min (p < or 0.01), sleep efficiency from 89.7 to 83.5% (p < or = 0.01), and percent rapid eye movement (REM) sleep from 18.8 to 15.1% (p < or = 0.01), and prolonged initial sleep latency (ISL) from 6.7 to 18.2 min (p < or = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Cutaneous↗
PubMed1992

The birth control pill revisited.

The evolution of oral contraceptives is summarized in this chapter. The social context into which the birth control pill was introduced, early and recent formulations of the pill, side effects, and the identification of serious complications of taking the pill are presented. The role of the nurse as a health educator of women and the responsibility of nurses to assist patients to make informed decisions about their reproductive function are emphasized. The outlook for future research and development of alternative forms of contraception is discussed.

Adolescent↗
PubMed1991

Influence of sleep state on CO2 responsiveness. A study of the unloaded respiratory pump in humans.

We measured the ventilatory recruitment threshold for CO2 (RT) during wakefulness, nonrapid eye movement sleep (NREM), and rapid eye movement sleep (REM) in eight patients with respiratory failure. Because the lungs were mechanically ventilated during the RT measurements, we were able to define the effects of arousal state on the chemoresponsiveness of the unloaded respiratory system. Ventilator settings were held constant in each patient, assuring that mechanoreceptor input to the respiratory controller remained the same during all measurements. RT increased from 38 +/- 6 mm Hg during relaxed wakefulness to 42 +/- 8 mm Hg during NREM sleep (p less than or equal to 0.01), consistent with a blunting of chemoresponsiveness during sleep. In five subjects we were able to measure RT during REM sleep also. In four of them, REM RT exceeded the wakefulness measurement by at least 3 mm Hg. The remaining patient showed no demonstrable changes in RT during either sleep state. We conclude that the loss of a wakefulness stimulus contributes to sleep-induced hypercarbia in humans.

Adult↗
PubMed1986

An ultrastructural comparison of neuromuscular junctions in normal and developmentally arrested Rana pipiens larvae: limited maturation in the absence of metamorphosis.

Neuromuscular junctions in the rectus abdominis muscles of normal and developmentally arrested Rana pipiens larvae were studied with freeze fracture and conventional electron microscopy to determine whether structural aspects of junctional maturation depend on metamorphosis. Comparison was made between junctions in premetamorphic larvae 1-3 months old and junctions in larvae that had remained in premetamorphosis for more than a year (more than four times as long as normal). In most respects, junctions from the two groups of larvae were similar. Unlike adult junctions, nerve-muscle contacts in both larval groups were pleomorphic and often involved more than one neuronal process; Schwann cell processes very rarely extended between nerve and muscle. Active zone structure ranged from total disorganization to an adult pattern of highly ordered double rows of particles aligned over junctional folds. Only quantitative analysis revealed differences between junctions in old and young larvae. The older larvae had fewer nerve-muscle contact sites involving multiple neuronal elements and a higher ratio of active zone length to presynaptic membrane area, although the mean active zone length was the same in the two groups. The results indicate that the maturation of junctional shape, the branching pattern of the axons, and the relationship of presynaptic axons to Schwann cells must be directly or indirectly dependent on the hormonal or behavioral changes associated with metamorphosis.

Animals↗
PubMed1984

Chest wall motion in sleep apnea.

Patterns of rib cage (RC) and abdomen (ABD) motion obtained from a respiratory inductive plethysmograph were studied during disordered breathing events - obstructive apnea, obstructive hypopnea, mixed apnea, and central apnea - in 54 patients with sleep apnea. The type of disordered breathing event was verified by esophageal pressure and bias-flow mask recordings. Obstructive apnea occurred to a variable extent in all patients and was characterized by stereotyped paradoxical motion of the RC or ABD or both in 49 patients (91%). There was no paradox in 2 patients with "feeble" inspiratory effort during obstructions and in 3 patients with normal inspiratory effort during obstructed breaths. The more obese patients displayed paradox of the ABD rather than of the RC. Paradox did not occur in central apnea or in the central component of mixed apnea. Obstructive hypopnea was characterized by paradox during part of the breath. We conclude that RC and ABD motion can adequately characterize apnea in most patients and thus avoid invasive monitoring techniques that can adversely affect sleep. However, if chest wall motion suggests that all apneas are central, a direct measurement of respiratory effort is necessary to exclude obstruction.

Adult↗