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Biomedical subjects

D D Peterson

Publications and source records attributed to D D Peterson.

At least 19 recordsLinked to original sources
PubMed2000

Potential novel predictors of mortality in end-stage renal disease patients with sleep disorders.

Patients with end-stage renal disease (ESRD) have an annual mortality rate exceeding 20%, although some survive many years. The ESRD population has a high incidence of sleep disorders, including sleep apnea and periodic limb movements in sleep (PLMS). Sleep disorders result in sleep deprivation, which can negatively affect immune function and cardiovascular-related outcomes, common causes of death in patients with ESRD. This study examined predictors of mortality in patients with ESRD with sleep problems. Twenty-nine consecutive patients with ESRD reporting disrupted sleep or daytime sleepiness were studied by all-night polysomnography. All patients were followed up until death, transplantation, or study termination. Among the variables studied, including such previously reported predictors as serum albumin level, urea reduction ratio, and hematocrit, only the PLMS index (PLMSI), arousing PLMSI (APLMSI), and total number of arousals per hour of sleep significantly predicted mortality. The 20-month survival rate with a PLMSI less than 20 was greater than 90% versus 50% for a PLMSI of 20 or greater (exact log-rank, P = 0.007). For the deceased versus survivor groups, mean PLMSI was 119.1 versus 19.8 (P = 0.01) and APLMSI was 48.1 versus 7.8 (P = 0.00006), with a mean survival of 10.3 versus greater than 25.5 months, respectively (P = 0.001). Median survival of patients with a PLMSI greater than 80 was only 6 months. PLMSI, APLMSI, and total arousals per hour of sleep were strongly associated with mortality in patients with ESRD with sleep disorders independent of other factors and may be novel predictors of near-term mortality.

Aged↗
PubMed1999

A preliminary study of the effects of correction of anemia with recombinant human erythropoietin therapy on sleep, sleep disorders, and daytime sleepiness in hemodialysis patients (The SLEEPO study).

End-stage renal disease (ESRD) is commonly associated with complaints of disturbed sleep and sleep disorders, frequently related to periodic limb movements in sleep (PLMS) or sleep apnea that may result in daytime sleepiness and other sequelae. Improvements in quality of life, including subjective sleep quality, have been reported in ESRD patients treated with recombinant human erythropoietin (rHuEPO). We investigated the objective effects of normalizing hematocrit on sleep disorders, sleep patterns, and daytime ability to remain awake in ESRD patients. Ten hemodialysis patients with sleep complaints while on rHuEPO therapy were studied by polysomnography while moderately anemic (mean hematocrit, 32.3%) and again when hematocrit was normalized (mean hematocrit, 42.3%) by increased rHuEPO dosing. Sleep patterns and associated parameters were monitored. Delivered dialysis dose and iron storage factors were monitored. Maintenance of Wakefulness Testing (MWT) was performed to assess daytime alertness/sleepiness. All 10 subjects experienced highly statistically significant reductions in the total number of arousing PLMS (P = 0.002). Nine of 10 subjects showed reductions in both the Arousing PLMS Index (P < 0.01) and the PLMS Index (P = 0.03) when hematocrit was normalized. Measures of sleep quality showed trends to improved quality of sleep. MWT demonstrated significant improvement in the length of time patients were able to remain awake (9.7 versus 17.1 minutes; P = 0.04). RHuEPO therapy with full correction of anemia reduces PLMS, arousals from sleep, and sleep fragmentation while allowing for more restorative sleep and improved daytime alertness. These findings may explain one mechanism for the improved quality-of-life parameters reported in ESRD patients treated with rHuEPO.

Adult↗
PubMed1999

Longitudinal and cross-sectional analysis of HEALTH WATCH data with a subset of perimenopausal women and matched controls.

HEALTH WATCH is a longitudinal prospective study of healthy aging. This study began in 1970. It characterizes the biochemical, hematological, immunological, and physiological data of 2200 healthy men and women between the ages of 20 and 80. Well-being, stress, and sleep data are obtained annually as a self-administered HEALTH WATCH questionnaire. A subset of women from the HEALTH WATCH cohort who were actively followed in the 1970s and had perimenopausal years available was selected. This subset allows observation of the normal female aging related to the significant marker, cessation of menses. Critical selection criterion included a natural menopause and the absence of hormonal intervention. Computer selection identified 19 subjects. Three sets of matched, age-defined controls were selected. This study investigates changes of data from healthy women related to menopause status. Changes unique to perimenopause status include sleep, sex difficulties, alkaline phosphatase, phosphorous, and thyroxine.

Adolescent↗
PubMed1996

Nocturia. A rarely recognized symptom of sleep apnea and other occult sleep disorders.

BACKGROUND: Nocturia, awakening from sleep to urinate, is a common symptom in a variety of medical disorders and in the elderly. Awakening from sleep as a result of nocturia is thought to be secondary to a sensation of urinary urgency resulting from an overextended bladder. Nocturia-related awakenings cause significant sleep disruption and fatigue in elderly patients and are correlated with an increased number of falls at night. Sleep disorders such as sleep apnea are also common in the elderly and are frequently the source of awakenings from sleep. The high incidence of both nocturia and sleep disorders in the elderly and other groups of patients suggests that sleep disorders may be the source of some awakenings from sleep usually attributed by patients to nocturia. Nocturia secondary to sleep disorders would be causatively different from nocturia secondary to pressure to urinate in common medical disorders and would require different diagnostic procedures and treatment. OBJECTIVE: To determine the frequency of nocturia as a symptom of primary sleep disorders. METHODS: Eighty consecutive patients, 27 women and 53 men with a mean (+/-SD) age of 58.7+/-14.1 years, undergoing polysomnography (sleep study or PSG) for the evaluation of a suspected sleep disorder and who met the sole criteria of awakening from sleep at least once and urinating voluntarily. Each patient had either a standard PSG recording or a PSG with administration of nasal continuous positive airway pressure. Immediately after each episode of nocturia during the PSG, patients were questioned about the reason they believed they had awakened. The PSG record immediately before awakening from sleep was then reviewed for potential causes of awakening. Patients were also asked on final morning awakening to fill in a questionnaire regarding their awakenings during the prior night. Patient reports were compared with the PSG to determine the accuracy of subjective reports. RESULTS: Patients awakened from sleep and voluntarily urinated a mean (+/- of 1.5+/-0.75 times per night for a total of 121 awakenings for the group. The majority (79.3%) of these awakenings from sleep were found to be directly secondary to sleep apnea, snoring or periodic leg movements in sleep. Patients correctly identified the source of their awakening from sleep on only five(4.9%) occasions and only once was sleep apnea correctly cited by a patient as a source of awakening during the night. CONCLUSION: Most awakenings from sleep attributed by our patients to pressure to urinate were instead a result of sleep disorders, particularly sleep apnea. The fact that patients do urinate once awake likely contributed to faulty post hoc reasoning and might have limited further inquiry by patients and their physicians in clinical settings into the actual sources of awakening from sleep. Even in those patients with well-known medical reasons for noctruria, Sleep disorders were still found to be the source of almost all awakenings from sleep. Patients were extremely poor judges of the reasons they awoke from sleep. The diagnosis of a sleep disorder should be seriously considered whenever a patient reports frequent awakenings from sleep to urinate.

Adult↗
PubMed1995

Night terrors in an adult precipitated by sleep apnea.

Parasomnias are generally described as disorders of arousal that arise out of stage 3 and 4 nonrapid eye movement (NREM) sleep without identifiable cause. We present a case of a 35-year-old man who during nasal continuous positive airway pressure (nCPAP) treatment for severe obstructive sleep apnea experienced an intense night terror triggered by a residual obstructive apnea during rebound deep sleep. The role of rebound deep sleep was thought to be essential in creating a state of sleep with a high arousal threshold hypothesized to be important for the occurrence of parasomnias. This case supports the clinical wisdom that identifiable sources of arousal can trigger parasomnias.

Humans↗
PubMed1995

Transient ischemic attacks and minor stroke during sleep. Relationship to obstructive sleep apnea syndrome.

BACKGROUND: It is reported that 13% to 44% of all cerebrovascular accidents (CVAs) occur during sleep. In addition to other well-known risk factors, snoring, sleep apnea, obesity, and daytime sleepiness have been shown to significantly increase the risk of stroke. We describe two cases that support the statistical relationship between snoring, sleep apnea, and CVA during sleep. CASE DESCRIPTIONS: In the first case, motor aphasia was noted in a 64-year-old, 5-ft, 1-in, 218-lb woman when she awakened from sleep at approximately 4 AM. This completely resolved within 3 hours. During her subsequent hospitalization she was found to have severe obstructive sleep apnea that responded well to treatment with nasal continuous positive airway pressure. There has been no recurrence of symptoms in this patient. The second patient was a 59-year-old, 5-ft, 6-in, 260-lb woman who presented to the Sleep Disorders Center with signs and symptoms of severe sleep apnea. In addition, she had awakened from sleep approximately 6 months earlier with numbness and weakness on her right side. Although these symptoms had greatly improved, she continued to complain about residual weakness that was worse on awakening from sleep. Sleep studies confirmed severe obstructive sleep apnea that responded very well to treatment with nasal continuous positive airway pressure. CONCLUSIONS: Snoring and obstructive sleep apnea not only increase the statistical risk of CVA but could be the proximal trigger that precipitates these events during sleep. These two cases provide clinical support for this relationship. Successful diagnosis and treatment of obstructive sleep apnea in the patient with transient ischemic attacks and minor stroke may be an important tool for preventing recurrence.

Female↗
PubMed1995

Ramp abuse. A novel form of patient noncompliance to administration of nasal continuous positive airway pressure for treatment of obstructive sleep apnea.

Administration of nasal continuous positive airway pressure (NCPAP) is the treatment of choice for most patients with obstructive sleep apnea. Many patients experience side effects with NCPAP use, and the compliance rate is reported to vary between 46-89%. The ramp is a device found on many NCPAP machines that resets the pressure to 3 cm H2O and then slowly increases the pressure to the prescribed pressure over a period of up to 45 min. The ramp allows patients time to fall asleep before the higher and likely more uncomfortable prescribed pressure is administered. We present a case in which a patient's repeated remote-controlled activation of this ramping feature severely limited effective therapy even when the NCPAP mask was properly in place, the machine was on, and the patient was breathing nasally.

Female↗
PubMed1993

Sleep disordered breathing in ESRD: acute beneficial effects of treatment with nasal continuous positive airway pressure.

Complaints about sleep and daytime alertness are common in ESRD patients. Eight consecutive ESRD patients with a sleep complaint were studied with all-night polysomnography. All were found to have significant sleep apnea with a mean apnea/hypopnea index (AHI) of 64 +/- 41.6 episodes per hour of sleep (range 7.5 to 140/hr of sleep). The majority of apneas were of the central or mixed variety causing severe fragmentation of sleep and frequent awakenings. Treatment was attempted with nasal continuous positive airway pressure (NCPAP). NCPAP was highly successful in six of the eight patients, reducing the mean AHI to normal or near normal levels (6.0 +/- 3.8/hr of sleep, P < 0.02 vs. baseline). The quality of sleep was significantly improved with statistically significant decreases in light stage 1 sleep, and nocturnal oxygenation improved with statistically significant increases in low SaO2 values. Five of six responders reported that they awoke feeling more alert and fewer times from sleep. The etiology of sleep apnea in ESRD is unknown although the frequent central apneas suggest a dysfunction of central respiratory control resulting from the effects of renal failure. Sleep-related complaints in patients with ESRD are likely to result from sleep apnea, a sleep disorder that can be diagnosed with polysomnography and treated with NCPAP.

Body Weight↗
PubMed1989

Infection with Mycobacterium avium complex in patients without predisposing conditions.

Pulmonary disease caused by Mycobacterium avium complex usually occurs in patients with chronic lung disease or deficient cellular immunity, and its prevalence is increasing. We describe 21 patients (mean age, 66 years) with such infection without the usual predisposing factors, representing 18 percent of the 119 patients surveyed. Seventeen women and 4 men were given a diagnosis of M. avium complex from 1978 to 1987, with a stable incidence over the decade, on the basis of pulmonary symptoms, abnormalities on chest films, positive cultures, and in 14, biopsy evidence of invasive disease. Most of the patients (86 percent) presented with persistent cough and purulent sputum, usually without fever or weight loss. The cough was present for a mean of 25 weeks before the correct diagnosis was made. Radiographic patterns of slowly progressive nodular opacities predominated (71 percent); only five patients had cavitary disease at presentation. All patients responded initially to antimycobacterial therapy, but eight eventually relapsed when it was stopped. Four patients died of progressive pulmonary infection caused by M. avium complex. The extent of the initial pulmonary involvement was greater in patients with progressive disease than in those whose condition improved. We conclude that pulmonary disease caused by the M. avium complex can affect persons without predisposing conditions, particularly elderly women, and that recognition of this disease is often delayed because of its indolent nature.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Evidence that the 116 kDa component of kinesin binds and hydrolyzes ATP.

Kinesin was prepared from bovine brain as described previously for studies of translocation. A major component of kinesin, (116 kDa) was shown to undergo specific photocrosslinking with [alpha-32P]ATP, indicating it was an ATP-binding polypeptide. A low ATPase activity associated with kinesin was stimulated up to 5-fold by microtubules to a specific activity of 14 nmol . min-1 . mg-1. N-Ethylmaleimide inhibited both [alpha-32P]ATP binding to the 116 kDa polypeptide and microtubule-stimulated ATPase activity, suggesting that the 116 kDa polypeptide was the catalytic subunit of kinesin. Though the ATPase activity associated with kinesin is low, it may be sufficient to support motility assuming it is coupled to the velocity of translocation.

Adenosine Triphosphatases↗
PubMed1986

Evidence for functional differences between two flagellar dynein ATPases.

Energy coupling in flagellar motility was investigated using demembranated, reactivated sea urchin spermatozoa (Arbacia punctulata). The ATP-dependence of ATPase activity was investigated for ATP concentrations ranging from 4 microM to 600 microM ATP. Using Eadie-Scatchard plot analysis, we identified two axonemal dynein ATPase activities. Their apparent Michaelis constants were calculated to be equal to 4 microM and 161 microM ATP, and they were referred to, respectively, as the high-affinity dynein ATPase (HADA) and the low-affinity dynein ATPase (LADA). Investigation of movement-coupled ATPase activity (difference between the ATPase activities of reactivated and broken, immotile spermatozoa) indicated that HADA and LADA were both 65% movement-coupled. The apparent Michaelis constants of movement-coupled HADA and LADA, 12 microM and 271 microM ATP, respectively, were two- to four-fold greater than the apparent Michaelis constants of movement-uncoupled HADA and LADA. The apparent Michaelis constants for force generation and beat frequency of reactivated spermatozoa were determined to be 24 microM and 290 microM ATP, respectively. These results raise the possibility that flagellar force generation is controlled primarily by movement-coupled HADA, and that flagellar beat frequency is controlled primarily by movement-coupled LADA. Thus, mechanochemical activity in flagellar motility may be divided between two enzymatically and functionally distinct classes of flagellar dyneins.

Adenosine Triphosphatases↗
PubMed1986

Effects of AV sequential versus asynchronous AV pacing on pulmonary hemodynamics.

We studied the effects of various pacing modes on cardiac hemodynamics and pulmonary gas alterations in chronic heart blocked dogs. Changing the pacing mode from an atrioventricular interval of 100 ms (AV100) to a ventriculo-atrial interval of 100 ms (VA100) caused a significant fall in left ventricular pressure (117.64 +/- 11.91 to 95.60 +/- 16.58 mmHg) and cardiac output from 2.18 +/- 0.24 to 1.46 +/- 0.20 L/min. Following the change in pacing mode from AV100 to VA100, there was an increase in the alveolar-arterial O2 gradient from 23.28 +/- 6.97 to 28.74 +/- 8.43 mmHg and a decrease in the arterial CO2 tension from 32.42 +/- 3.22 to 29.42 +/- 3.22 mmHg. There was also a decrease in arterial CO2 tension when the AV100 pacing mode was compared to asynchronous ventricular pacing (32.42 +/- 3.22 versus 30.56 +/- 2.82 mmHg). The minute volume of O2 also decreased when the pacing mode was changed from AV100 to asynchronous ventricular pacing (0.134 +/- 0.01 versus 0.126 +/- 0.01 L/min) and decreased further at VA100 to 0.114 +/- 0.01 L/min. Other significant changes were also observed: the percent of expired CO2 decreased when the pacing mode was changed from AV100 to VA100 (3.68 +/- 0.13 versus 3.37 +/- 0.26%) or to asynchronous ventricular pacing (3.40 +/- 0.31%). The end-expiratory O2 increased and CO2 decreased when the pacing mode was changed from AV100 to VA100. The breath-by-breath correlation of end-expiratory O2 and CO2 with left ventricular systolic pressure showed an almost immediate increase in O2 and reduction in CO2 concentration associated with decreasing systolic pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Ventilatory response to hypercapnia before and after athletic training.

To assess the effect of athletic training on the slope (S) of the hypercapnic ventilatory response at rest, we prospectively studied 13 untrained young men. S was determined by the slope of the regression delta VI/delta PETCO2, calculated between 48 and 63 mm Hg during CO2 rebreathing. Six of the subjects trained for seven months as intercollegiate rowers while the remaining subjects underwent no training and served as controls. After training, the rowers had a significant increase in S during hypercapnia. No such change was seen in the untrained controls. These data suggest that athletic training in normal subjects increases CO2 sensitivity at rest.

Adolescent↗
PubMed1984

Effect of aging on ventilatory response to exercise and CO2.

Studies were performed to determine the effects of aging on the ventilatory responsiveness to two known respiratory stimulants, inhaled CO2 and exercise. Although explanation of the physiological mechanisms underlying development of exercise hyperpnea remains elusive, there is much circumstantial evidence that during exercise, however mediated, ventilation is coupled to CO2 production. Thus matched groups of young and elderly subjects were studied to determine the relationship between increasing ventilation and increasing CO2 production (VCO2) during steady-state exercise and the change in their minute ventilation in response to progressive hypercapnia during CO2 rebreathing. We found that the slope of the ventilatory response to hypercapnia was depressed in elderly subjects when compared with the younger control group (delta VE/delta PCO2 = 1.64 +/- 0.21 vs. 2.44 +/- 0.40 l X min-1 X mmHg-1, means +/- SE, respectively). In contrast, the slope of the relationship between ventilation and CO2 production during exercise in the elderly was greater than that of younger subjects (delta VE/delta VCO2 = 29.7 +/- 1.19 vs. 25.3 +/- 1.54, means +/- SE, respectively), as was minute ventilation at a single work load (50 W) (32.4 +/- 2.3 vs. 25.7 +/- 1.54 l/min, means +/- SE, respectively). This increased ventilation during exercise in the elderly was not produced by arterial O2 desaturation, and increased anaerobiasis did not play a role. Instead, the increased ventilation during exercise seems to compensate for increased inefficiency of gas exchange such that exercise remains essentially isocapnic. In conclusion, in the elderly the ventilatory response to hypercapnia is less than in young subjects, whereas the ventilatory response to exercise is greater.

Adult↗
PubMed1983

Central sleep apnea in hypothyroidism.

This is a report of a 45-yr-old male patient who developed central sleep apnea syndrome because of hypothyroidism. In response to L-thyroxine therapy, the patient became euthyroid, and the apneic phenomenon disappeared. Previous reports have suggested that hypothyroidism can produce obstructive sleep apnea from either narrowing of the upper airway secondary to deposition of mucopolysaccharides and protein extravasation into the tissues or from abnormalities in ventilatory control. The present patient did demonstrate evidence of profound dysfunction of his respiratory control center: before therapy, the patient manifested blunted ventilatory and occlusion pressure responses to hypoxia and normal responsiveness to hypercapnia; after therapy, hypoxic responsiveness was restored and the ventilatory response to hypercapnia doubled. Hypothyroidism should be included in the differential diagnosis of central sleep apnea.

Diagnosis, Differential↗
PubMed1982

Effect of aerosolized histamine on occlusion pressure and ventilation in humans.

To define further the mechanism by which inspiratory neural activity is increased in asthma, we studied the effect of aerosolized histamine on occlusion pressure (P100) and ventilation in conscious humans while end-tidal CO2 partial pressure was maintained at a constant, slightly hypercapnic level. The dose of histamine we employed varied from subject to subject but was such that it produced a 70% reduction in specific airway conductance in each subject. In 9 of the 13 subjects tested, inhaled histamine significantly increased P100. This increase was not due to changes in functional residual capacity, which was not affected by aerosolized histamine. Inhalation of isoproterenol abolished the effects of histamine on specific airway conductance and P100. Anesthesia of the airways by lidocaine eliminated the effect of histamine on P100 but did not alter the magnitude of the change in specific airway conductance produced by histamine. We conclude that the increase in occlusion pressure seen after the inhalation of histamine in humans depends on both contraction of bronchial smooth muscle and stimulation of airway receptors.

Adult↗
PubMed1981

Effects of aging on ventilatory and occlusion pressure responses to hypoxia and hypercapnia.

Studies were performed to examine the decrease in ventilatory response to hypoxia and hypercapnia in the elderly and to explore its etiology. For this purpose, matched groups of normal elderly (65 to 79 yr of age) and young subjects were used. Standard pulmonary function tests were supplemented in both groups by determination of total respiratory compliance and the ventilatory responses to hyperoxic hypercapnia and isocapnic hypoxia using rebreathing methods. While testing the ventilatory responses, we recorded minute ventilation and its components, as well as mouth occlusion pressures, and rib cage and abdominal-diaphragmatic compartmental ventilation (magnetometry). We found that ventilatory responses to both hypercapnia and hypoxia were reduced in the elderly by approximately 50%. These reductions were not related to any change in control of respiratory timing, but to a large reduction in mean inspiratory airflow. The reduced airflow could not be attributed to alterations in pulmonary mechanics since the differences in mechanics between the groups were small. Instead, since the occlusion pressure responses to hypercapnia and hypoxia were reduced in the elderly proportionately to the ventilatory responses, reduction in neuromuscular inspiratory output was likely to be the major factor.

Adult↗