Search PubMed⌕ Search

Biomedical subjects

W C Orr

Publications and source records attributed to W C Orr.

At least 127 records · Page 7Linked to original sources
PubMed1980

Respiratory mechanics and timing during sleep in occlusive sleep apnea.

Six human obese subjects with the sleep apnea hypersomnolence syndrome associated with upper airway occlusion (UAO) were studied during sleep to characterize respiration. Measurements included the timing components of ventilation, pulmonary resistance, flow, and esophageal and gastric pressures before and during UAOs. During the period between UAOs, the resistance progressively increased (9.4-18.1 cmH2O/l(-1) . s, P less than 0.05) as the ventilation decreased (1.82-0.77 l/s, P less than 0.05), but without changes in esophageal pressure swings. During this period, inspiratory time-to-total cycle time decreased (0.42-0.25 s, P less than 0.05) due to expiratory phase prolongation. The apnea began after expiration and terminated on inspiration with the maximal swings in esophageal and gastric pressure near the termination. During the UAO, the respiratory cycle time decreased slightly, but the expiratory pause time was significantly shortened immediately before ventilation. We suggest that the UAO is but one aspect of this syndrome and that a decrease in central nervous system activity diminishes the respiratory drive before the onset of the UAO.

Adult↗
PubMed1979

Hypersomnolent and nonhypersomnolent patients with upper airway obstruction during sleep.

When the syndrome consisting of sleep-induced apnea and hypersomnolence is due to upper airway obstruction, the hypersomnolence is believed to be the direct result of deprivation of sleep related to such obstructions. The purpose of this report is to describe a group of four asymptomatic subjects with upper airway obstruction during sleep. These subjects were matched with a group of patients with the syndrome of sleep-induced apnea and hypersomnolence. There were no significant differences between symptomatic and asymptomatic groups in terms of the absolute number of upper airway obstructions (252 vs 231), their mean duration (20.8 vs 25.9 seconds), the mean arterial carbon dioxide tension during sleep (39 vs 39 mm Hg), or the electroencephalographic patterns during sleep. The only variables that emerged as significantly different between the two groups were the weights (128 vs 90 kg; P less than 0.05), the low arterial oxygen pressure (PaO2) on waking (54 vs 80 mm Hg; P less than 0.002), and the lower PaO2 during sleep (47 vs 70 mm Hg; P less than 0.01) in the symptomatic patients. From these data, we conclude that the hypersomnolence in patients with sleep-induced apnea due to upper airway obstruction cannot be explained by deprivation of sleep, and other factors need to be carefully examined in future studies.

Adult↗
PubMed1979

Progesterone therapy in obese patients with sleep apnea.

Seven morbidly obese patients with sleep-related upper airway obstruction (UAO) were studied before and during progesterone treatment. All subjects had severe daytime somnolence, and five of the seven had congestive heart failure. All subjects were studied for one or two consecutive baseline nights in the sleep laboratory. Six of the seven subjects showed a mean of greater than 100 UAOs. Patients were treated for two to four weeks with medroxyprogesterone acetate, 20 mg three times daily. At the end of the treatment period, the sleep studies were repeated. There was no significant difference in the incidence, mean duration, or rate per minute of apneic episodes occurring before and with progesterone treatment. Severe hypoxemia during sleep persisted with treatment, as did the occurrence of cardiac arrhythmias. There was a significant improvement in the waking Pao2 with progesterone treatment.

Adult↗
PubMed1979

Nocturnal levels of growth hormone in hyperactive children of small stature.

Growth disturbances have been demonstrated in hyperactive children treated with stimulant medication. This study examines sleep related growth hormone secretion in patients with hyperactive syndrome and relative short stature. Five such patients were compared with 9 age matched controls. There were no differences in sleep patterns, and growth hormone levels for the hyperactive children were within normal limits. This study suggests that hyperactive children with short stature have normal sleep patterns and normal sleep related growth hormone secretion.

Body Height↗
PubMed1978

Diversity and abundance of polyadenylated RNA from Achlya ambisexualis.

The diversity, abundance, and DNA sequence representation of poly(adenylic acid) containing RNA derived from cells of Achlya ambisexualis cultured in defined and undefined media have been determined. The kinetics of hybridization of polyadenylated RNA with complementary DNA were the same for both culture conditions and revealed the presence of three frequency classes containing 29, 220, and 3000 different sequences of an average length of 1150 nucleotides. Complexity estimates derived from experiments in which polyadenylated RNA was hybridized to unique sequence DNA were in good agreement with these results. The kinetics of hybridization of complementary DNA with an excess of nuclear DNA indicate that approximately 10% of the RNA is transcribed from reiterated DNA sequences while the remainder is transcribed from single copy sequences.

Base Sequence↗
PubMed1977

Retrognathia and sleep apnea. A life-threatening condition masquerading as narcolepsy.

The association of sleep apnea with daytime hypersomnolence without obesity, and its potentially lethal cardiopulmonary sequelae, make it crucial that this condition be distinguished from narcolepsy. A patient with retrognathia who had been diagnosed as a narcoleptic for 15 years had the primary complaint of excessive daytime sleepiness. Sleep laboratory evaluation showed severe hypoxemia and a mean of 366 upper airway obstructions per night. The patient was treated with a tracheotomy; this resulted in relief of the sleep-related upper airway obstructions, hypoxemia, and hypersomnolence.

Airway Obstruction↗
PubMed1977

Sleep apnea, hypersomnolence, and upper airway obstruction secondary to adenotonsillar enlargement.

The authors examined four children with substantial adenotonsillar enlargement that caused intermittent severe upper airway obstructive episodes, documented by all-night polygraphic monitoring of sleep and respirations. Previously unreported complications of severe adenotonsillar enlargement that were demonstrated included prolonged obstructive apneic episodes and disturbed sleep patterns. The children also exhibited daytime hypersomnolence. Polygraphic sleep studies after adenotonsillectomy confirmed improved sleep patterns and relief of the obstructive episodes. None of our patienqs had developed pulmonary hypertension, cor pulmonale, or other reported complications of prolonged upper airway obstruction, all of which may have been averted by early diagnosis and treatment.

Adenoidectomy↗
PubMed1977

Sleep disturbances after open heart surgery.

This study was designed to document quantitatively the sleep disturbances that occur after open heart surgery and to investigate a group of patients who underwent a thoracic surgical procedure not involving cardiopulmonary bypass. Nine patients were studied, six after open heart surgery and three after partial or complete pneumonectomy. In each patient, sleep patterns were recorded with use of all night polygraphy before and after operation and for up to 5 weeks on follow-up studies. After open heart surgery, patients manifested considerable suppression of both rapid eye movement and slow wave sleep patterns. In the three patients subjected to thoracotomy these sleep indexes returned to preoperative levels much earlier. Evidence of stage 2 sleep was present in one of the three patients with thoracotomy on the first postoperative night, and in two of the three both rapid eye movement and slow wave sleep returned to preoperative levels by the time of hospital discharge. It is concluded that patients undergoining open heart surgery experience both acute and chronic disruptions of sleep that last well beyond the hospital period of convalescence. These sleep disturbances have considerable relevance for postoperative management.

Adult↗
PubMed1977

Sleep patterns in growth hormone deficient children and age-matched controls: developmental considerations.

Ten patients with isolated growth hormone (GH) deficiency and 13 age-matched normal controls were studied. All patients were below the 3rd percentile in height and weight. All but 1 subject were studied for 3 or 4 consecutive nights in the sleep laboratory which included monitoring of the EEG, EOG, EMG, and EKG. GH samples were taken during sleep in 6 of the 10 patients. There were no significant differences in the slow-wave sleep (SWS) parameter between the 2 groups, nor was there any difference when all growth hormone patients were compared to controls. The age group comparisons for the percent of rapid eye movement (REM) sleep parameter revealed a significant difference between GH and controls for the youngest group only (p less than 0.05). Similar results were obtained when the GH subjects were grouped according to bone age. A significant decline in SWS was found with increasing chronological age (p less than 0.02), while the REM parameter did not show any significant changes across age categories. None of the patients showed a sleep-related peak in GH secretion. These data are not compatible with the hypothesis of a monotonic relationship between SWS and GH secretion.

Adolescent↗
PubMed1976

Inhibition of gastric acid secretion by blood drawing from an indwelling venous needle.

To investigate a possible inhibitory effect of blood drawing through an indwelling forearm vein needle on gastric acid secretion, 11 subjects were studied on four occasions each. The first session was for adapting the subject to the 3-hr collection of gastric juice. In 7 subjects the second through fourth sessions gave three conditions in balanced order: (1) an indwelling forearm vein needle and the withdrawal of 5 or 10 cc of blood every 20 min, (2) only a nonfunctional "dummy" needle implanted subcutaneously in the forearm skin, and (3) the control condition with no needle. In four additional subjects the sessions were identical except that condition (1) involved an indwelling forearm vein needle kept open by a slow infusion of saline solution and no blood was drawn. Phenol red recovery from an initial intragastric injection was measured in all. Results showed that blood drawing, but not saline infusion or venipuncture per se, inhibited gastric acid output.

Adult↗
PubMed1976

Stress, cardiac activity and sleep.

An overview is presented of the relationship between cardiovascular activity and sleep, emphasizing the interrelations between stage of sleep and cardiovascular dysfunction. Possible implications of the data are discussed, especially in relation to stress-related factors and possible treatment regimens.

Cardiac Surgical Procedures↗
PubMed1976

Sleep patterns and gastric acid secretion in duodenal ucler disease.

Five normal volunteers and five patients with duodenal ulcer (DU) disease were studied for five consecutive nights. All subjects underwent placement of a nasogastric tube, continuous collection of gastric juice, and continuous electroencephalographic monitoring of sleep. Gastric juice was collected in 20-minute samples by remote suction (Gomco). Blood samples were drawn every 20 minutes on the third night via an indwelling venous needle. Results showed no significant correlations between the sleep variables and the gastric acid secretion measures or between the sleep variables and serum gastrin levels. Acid secretion decreased from hour 1 to hour 2 in controls and in patients with inactive DU disease, while it increased in patients with active DU disease. Each subject had at least one night of recording in which continuous gastric secretion was less than 0.1 mEq per 20-minute sample. It appears unlikely that the gastric discomfort of DU patients can be attributed to acid hypersecretion triggered by rapid eye movement sleep.

Duodenal Ulcer↗