Respiratory responses to tracheobronchial stimulation during sleep and wakefulness in the adult cat

The response to tracheal stimulation (50 microliters of tap water) during wakefulness, non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep was investigated in adult cats. In wakefulness, repetitive coughing occurred on 80% of the trials. In NREM and REM sleep, the most frequent response (approximately 69% and 58% of the trials, respectively) was arousal, followed by coughing. Apneas occurred following the stimulus and before arousal in 11% and 24% of the trials in NREM and REM sleep, respectively. In NREM sleep, the tracheal stimulus sometimes evoked expiratory efforts following a normal inspiratory effort (11% of the trials). These were much weaker than the expiratory efforts during coughing in wakefulness. In REM sleep, stimulation in 11% of the trials elicited increased inspiratory efforts. Although these may have been diminutive preparatory inspirations for coughing, they were much smaller than preparatory inspirations associated with coughing in wakefulness, and they were never followed by active expiratory efforts. Arousal from either NREM or REM sleep in response to tracheal stimulation was sometimes associated with an augmented breath. This response, which is common upon spontaneous arousal, may lead to deeper aspiration of the tracheal fluid. We conclude that in cats coughing requires wakefulness and that airway stimuli in sleep cause a variety of respiratory responses, some of which may be maladaptive.     

Psychomotor development in infants and young children

The functional relationship between brain catecholamines and serotoninergic function was studied in stress-naive and chronically immobilized rats after blockade of catecholamine synthesis with alpha-methyl-p-tyrosine (alpha MpT). The levels of noradrenaline (NA), serotonin, and 5-hydroxyindole acetic acid (5-HIAA) in pons plus medulla, brainstem, hypothalamus, hippocampus, and frontal cortex, and those of 3-methoxy, 4-hydroxyphenile-tileneglicol sulphate (MHPG-SO4) in the hypothalamus were measured by HPLC. Chronic immobilization (IMO) resulted in higher NA levels in pons plus medulla and hypothalamus, the latter area (the only one in which the NA metabolite was determined) also showing slightly elevated MHPG-SO4 levels as compared to stress-naive rats. Chronic IMO did not alter either serotonin or 5-HIAA levels, but acute stress consistently increased 5-HIAA levels in all areas, independently of previous chronic stress. Administration of alpha-MpT drastically reduced NA and increased 5-HIAA levels in all brain regions excepting the frontal cortex. The effect of the drug on serotoninergic function was not altered by previous chronic exposure to IMO. These data suggest that the noradrenergic system appears to exert a tonic inhibitory effect on serotoninergic activity in the brain, with the intensity of the effect depending on the brain area studied. In addition, chronic stress does not appear to alter the functional relationship between noradrenergic and serotoninergic activities, although interactions might exist in more restricted brain areas; this deserves further study.     

Phimosis of infants and young children in Japan

Bacterial and viral infections may be associated with the onset of a number of autoimmune diseases and relapses of these conditions. We describe a patient in whom there was a close temporal relationship between a suppurative wound infection and the onset of microscopic polyarteritis. The clinical features of this disease responded to treatment with high dose prednisolone and cyclophosphamide. The patient had several further infective episodes while being treated, but there were no disease exacerbations or relapses related to these. Anti-neutrophil cytoplasmic antibodies (ANCA) were never demonstrated in this patient. Thus while it is likely that the infection precipitated the onset of the systemic vasculitic illness, this occurred independently of ANCA.     

Respiratory changes associated with rapid eye movements in normo- and hypercapnia during sleep

Rapid eye movements during rapid-eye-movement (REM) sleep are associated with rapid, shallow breathing. We wanted to know whether this effect persisted during increased respiratory drive by CO2. In eight healthy subjects, we recorded electroencephalographic, electrooculographic, and electromyographic signals, ventilation, and end-tidal PCO2 during the night. Inspiratory PCO2 was changed to increase end-tidal PCO2 by 3 and 6 Torr. During normocapnia, rapid eye movements were associated with a decrease in total breath time by -0.71 +/- 0.19 (SE) s (P < 0.05) because of shortened expiratory time (-0.52 +/- 0.08 s, P < 0.001) and with a reduced tidal volume (-89 +/- 27 ml, P < 0.05) because of decreased rib cage contribution (-75 +/- 18 ml, P < 0.05). Abdominal (-11 +/- 16 ml, P = 0.52) and minute ventilation (-0.09 +/- 0.21 ml/min, P = 0.66) did not change. In hypercapnia, however, rapid eye movements were associated with a further shortening of total breath time. Abdominal breathing was also inhibited (-79 +/- 23 ml, P < 0.05), leading to a stronger inhibition of tidal volume and minute ventilation (-1.84 +/- 0.54 l/min, P < 0.05). We conclude that REM-associated respiratory changes are even more pronounced during hypercapnia because of additional inhibition of abdominal breathing. This may contribute to the reduction of the hypercapnic ventilatory response during REM sleep.     

Respiratory effects of desflurane anesthesia on spontaneous ventilation in infants and children

Volatile anesthetics depress spontaneous ventilation in a dose-dependent manner with variations in effects among different drugs. The goal of this prospective study was to assess respiratory changes during spontaneous ventilation using desflurane/O2/N2O anesthesia in two groups of children. Both groups were undergoing minor surgery and consisted of children < 2 yr old (Group I) and children > 2 yr old (Group II). They were examined at 0.5, 1, and 1.5 minimum alveolar anesthetic concentration desflurane anesthesia. Induction of anesthesia was performed via a face mask and a mixture of O2/N2O (40:60) with halothane. At lease 20 min after stopping halothane, the respiratory variables were recorded on desflurane anesthesia. Tidal volume and minute ventilation decreased significantly (P <0.05) as desflurane increased from 0.5 to 1.5 MAC in both groups. At 1.5 MAC, the respiratory rate was greater in Group II than in Group I (P <0.05). In both groups, the increase in end-tidal CO2 was significant at 1.5 MAC versus 1 and 0.5 MAC (P <0.05). Apnea, i.e., no respiratory movement for 20 s, occurred at 1.5 MAC in one patient in each group. The respiratory duty cycle did not change in any of the groups. Both indices of paradoxical respiration--amplitude index and delay index--did not change. IMPLICATIONS: Desflurane induces respiratory depression at concentrations higher than 1 minimum alveolar anesthetic concentration mainly due to a decrease in tidal volume. Therefore, desflurane at high concentrations should be used cautiously in infants and children with spontaneous ventilation.     

Hemodynamics in sleep-induced apnea. Studies during wakefulness and sleep

Twelve patients with predominantly obstructive type sleep apnea underwent cardiac catheterization, hemodynamic monitoring, and arterial blood gas analysis during wakefulness and sleep. Abnormalities during wakefulness included systemic hypertension in four of 12, exercise-induced mild pulmonary hypertension in five of 12, and alveolar hypoventilation in one. During sleep nine patients had cyclic elevations of arterial pressure with each apneic episode, exceeding 200 mm Hg systolic in three of 12. Pulmonary artery pressures increased in 10 of 12, exceeding 60 mm Hg systolic in five. Marked degrees of hypoxemia (arterial P02, less than 50 mm Hg in eight of 12) and moderate hypercapnia with respiratory acidosis were associated with these hemodynamic changes. Cyclic upper airway obstruction during sleep may result in hypercapnia, acidosis, and pronounced hypoxemia, which can lead to hemodynamic abnormalities during sleep. Sustained pulmonary hypertension and possibly systemic hypertension may follow. Tracheostomy is an effective therapy and is recommended to symptomatic patients who have predominantly obstructive apnea but no relievable anatomic cause of upper airway obstruction.     

Tympanometric detection of middle ear effusion in infants and young children

Tympanometry, a test of middle ear status new to clinical pediatrics, was carried out on 280 subjects, 10 days through 5 years of age. The tympanograms obtained were compared with otoscopic findings and, in 107 of the subjects, with findings at myringotomy. Seven distinct tympanometric curve types were identified and defined, based on their degree of correlation with the presence or absence of middle ear effusion. In subjects 7 months of age and older, curves suggesting normal (high) tympanic membrane compliance in combination with atmospheric or near-atmospheric middle ear air pressure were rarely associated with effusion. Conversely, curves suggesting low tympanic membrane compliance were highly correlated with the presence of effusion. Curves suggesting intermediate compliance or reduced middle ear air pressure were also correlated with effusion, but the degree of correlation was dependent on the shape of the curve. In infants less than 7 months of age, many of the ears with effusion had "normal" tympanograms, presumably because external auditory canal walls in such infants tend to be highly distensible. Tympanometry is a simple, rapid, atraumatic, valid, and objective test, easily administered by paraprofessional personnel. Its use can result in improved detection of middle ear effusion and other middle ear abnormalities, and also appears to promote improvement in diagnostic acumen.     

Primary care of infants and young children with Down syndrome

Down syndrome is caused by triplicate material of chromosome 21. The syndrome has a variable physical expression, but congenital cardiac defects, transient myelodysplasia of the newborn and duodenal atresia are highly specific for this chromosomal disorder. Routine health maintenance is important because infants and children with Down syndrome are more likely to have otitis media, thyroid disease, congenital cataracts, leukemoid reactions, dental problems and feeding difficulties. Since infants with this syndrome are prone to respiratory infections, immunization recommendations should be followed closely. Motor, language, social and adaptive skills should be assessed at each office visit. The psychosocial aspects of care should be discussed with the parents of an infant with Down syndrome. If necessary, the parents should be referred to family support and specialty resources. Institutionalization of infants with Down syndrome is now unlikely. With newer surgical techniques, early therapy to minimize developmental delay and proper health supervision, the functional prognosis for infants with Down syndrome is considerably improved.     

Pupillometry as a measure of visual sensitivity among infants, young children, and adults.

Proposes pupillometry as an objective measure of visual sensitivity for infants, young children, and adults. To study the possible close relationship between pupillary contraction and perceived brightness for infants and young children, photopic pupillary sensitivity was measured for 5 1-yr-olds, 5 3-yr-olds, and 5 adults. Results support the utility of pupillometry as a sensitivity measure for infants and children, based on the demonstrated close agreement between the children's and adults' data in the study and adult data obtained by more traditional psychophysical techniques. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Periodic leg movements during sleep and sleep disturbances in elders

BACKGROUND: Periodic limb movements in sleep (PLMS) are an increasingly pervasive disturbance for aging adults. The aims of this experiment were: (a) to describe the index of periodic limb movements in sleep (myoclonus index [MI] in elderly subjects with complaints of poor sleep or depression (N = 22; 68 +/- 5.5 SD years); and (b) to correlate MI with sleep history, depression scores, and objective and subjective indices of sleep. METHOD: Sleep and leg movements were assessed for 5 consecutive nights. Between-subjects, nonparametric correlations were examined between mean MI and sleep history, depression scores, and objective and subjective sleep characteristics. Associations among within-subject night-to-night variabilities of MI, objective, and subjective variables were examined with repeated measures ANCOVA, entering MI as a covariate. RESULTS: A remarkably high level of MI was found (median 25.8 events per hour; 86% of subjects > 5). Nevertheless, no associations were found between MI and sleep disturbance measures. CONCLUSION: These results extend previous reports that PLMS are remarkably persuasive in elderly volunteers and support other reports questioning whether there is a distinct PLMS syndrome.     

Disturbances of wakefulness, sleep and respiratory function in Steinert's disease

36 night sleep recordings were carried out on 15 patients suffering from myotonia dystrophica. 9 of these patients complained of diurnal hypersomnia. 10 patients had a disturbance of night sleep with a reduction of REM sleep sometimes associated with interruption of the recording with an increase in the light stages of sleep or alternatively with an increase of REM sleep with a reduction in the latency period of the first paradoxical sleep or with narcoleptic elements. 13 patients had abnormally early abolition of chin EMG activity, almost on falling asleep. 11 cases had pathological apnoeic episodes during sleep and in 9 of the 10 patients who underwent respiratory function studies there was a restrictive airways defect. In addition 9 had frank hypoxia without hypercapnia and 4 a right to left shunt. 3 clinically unaffected patients but with affected relatives were also investigated, 2 were found to have sleep disturbances 1 of which was associated with early abolition of tone.     

Activity of medullary respiratory neurons during ventilator-induced apnea in sleep and wakefulness

Mechanical ventilation of cats in sleep and wakefulness causes apnea, often within two to three cycles of the ventilator. We recorded 137 medullary respiratory neurons in four adult cats during eupnea and during apnea caused by mechanical ventilation. We hypothesized that the residual activity of respiratory neurons during apnea might reveal its cause(s). The results showed that residual activity depended on 1) the amount of nonrespiratory inputs to the cell (cells with more nonrespiratory inputs had greater amounts of residual activity); 2) the cell type (expiratory cells had more residual activity than inspiratory cells); and 3) the state of consciousness (more residual activity in wakefulness and rapid-eye-movement sleep than in non-rapid-eye-movement sleep). None of the cells showed an activation during ventilation that could explain the apnea. Residual activity of approximately one-half of the cells was modulated in phase with the ventilator. The strength of this modulation was quantified by using an effect-size statistic and was found to be weak. The patterns of modulation did not support the idea that mechanoreceptors excite some respiratory cells that, in turn, inhibit others. Indeed, most cells, inspiratory and expiratory, discharged during the deflation-inflation transition of ventilation. Residual activity failed to reveal the cause of apnea but showed that during apnea respiratory neurons act as if they were disinhibited and disfacilitated.     

Neuronal correlates of sleep, wakefulness and arousal in a diurnal insect

The discovery that various states of sleep, rest, wakefulness and arousal in man can be correlated with specific forms of the electroencephalogram1 has led to intensive studies of these states, mostly in mammals2-5. Today it is generally accepted that circadian sleep-wakefulness cycles occur in mammals and birds2,3,6. Behavioural observations on sleep in moths have also been published7; many other invertebrates demonstrate rest/activity cycles8. Circadian sensitivity fluctuations in both central9 and peripheral10-15 components of the visual system of various nocturnal arthropod species have been demonstrated. We now report that long-term, extracellular, single-unit recordings from optomotor interneurones in the optic lobes of forager honey bees reveal an oscillation in their sensitivity to moving visual stimuli16, 17. The oscillation displays properties typical of a circadian rhythm6, 18. The sensitivity of the neurons is higher during the subjective day than during the subjective night. The locomotor activity of individual, fixed walking forager bees shows a similar circadian oscillation and is also higher during the subjective day. Visual and mechanical stimuli can act directly on the interneurones and restore their sensitivity during times of reduced neuronal responsiveness. A comparison with results available for mammals makes it likely that the neuronal phenomena presented here are correlates of the bee's circadian sleep-wakefulness rhythm.