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Biomedical subjects

J Krieger

Publications and source records attributed to J Krieger.

At least 163 records · Page 9Linked to original sources
PubMed1988

Objective measurement of compliance with nasal CPAP treatment for obstructive sleep apnoea syndrome.

Compliance with nasal continuous positive airway pressure (CPAP) has become a major concern, since this treatment is efficacious, but constraining. In 46 consecutive obstructive sleep apnoea (OSA) patients, we measured compliance with nasal CPAP by establishing a mean rate of use, with a built-in time counter read at three-month intervals, over a mean follow-up period of 232 +/- 27 days. The mean rate of use in the whole group was 5.14 +/- 0.31 hours per day. The acceptance rate was 90.9-93.2%, showing that patient acceptance is not a limitation in the use of nasal CPAP.

Female↗
PubMed1988

Craniofacial characteristics in patients with obstructive sleep apneas syndrome.

Obstructive sleep apneas syndrome (OSAS) has been associated with a clinical reduction of the pharyngeal spaces. To define whether predisposing skeletal craniofacial conditions exist in OSAS patients, 32 OSAS adult patients were compared in a cephalometric investigation with a control sample of 40 adults with ideal dentofacial traits. A t-test assessed the statistical significance of the differences in the two groups; correlation matrix tabulation and discriminant function analysis helped in the identification of the influence of different variables in segregation of the two populations. The following observations were made: There were no differences in maxillary or mandibular prognathism between the two groups. The sagittal dimension of the cranial base was significantly reduced in the OSAS sample, as was the bony pharyngeal opening and maxillary length. This posterior facial compression was associated with increased lower face height (p less than 0.01 in all cases). There were significant correlations in both groups between cranial base length or angulation and pharyngeal opening (p less than 0.01). Eighty percent of the population was correctly sorted out using the discriminant function analysis, with only eight controls and five OSAS patients misclassified. However, this analysis suggested that factors other than the cephalometric may be involved in OSAS.

Adult↗
PubMed1988

Renal function in patients with obstructive sleep apnea. Effects of nasal continuous positive airway pressure.

Patients with obstructive sleep apnea (OSA) often exhibit nocturnal polyuria, which disappears with nasal continuous positive airway pressure (CPAP) treatment. We measured water and electrolyte urinary excretion, creatinine and osmolal clearances, and water transport during sleep in 13 polygraphically monitored patients with OSA during two consecutive nights, either untreated or treated with nasal CPAP, and in eight normal subjects. Untreated patients with OSA had greater urinary flows and greater urinary sodium, chloride, and potassium excretions than did controls. Nasal CPAP treatment in patients with OSA resulted in a reduction in urinary flow and in sodium and chloride excretion, with a concomitant increase in sodium resorption. None of these effects was observed in CPAP-treated normal subjects. The only effect of nasal CPAP common to normal subjects and patients was a trend toward decreased glomerular filtration rate.

Adult↗
PubMed1987

[Sleep apnea syndromes in adults].

Sleep apnoea syndromes are a frequent disease, with an incidence of more than 1% in the adult population, a strong male predominance, and a maximal frequency between 40 and 60 years. Their clinical manifestations are dominated by snoring and daytime sleepiness, at times associated with morning headaches, intellectual deficiency, sexual impotence. Obesity, hypertension and polycythemia are not uncommon. These patients are at risk for accidents due to sleepiness, sudden death due to sleep apnoea-related cardiac arrhythmias, ischemic attacks related to hypertension and polycythemia and right heart failure secondary to pulmonary hypertension and alveolar hypoventilation. The most frequent form of sleep apnoea syndromes include obstructive and mixed apnoeas. Their mechanism involves both anatomic factors (upper airway narrowing) and functional factors (defective activation of upper airways dilatory muscles) which lead to upper airway occlusion upon inspiration during sleep. Two therapeutic strategies are possible: a surgical one, uvulopalatopharyngoplasty, the efficacy of which is inconstant and unpredictable and nasal continuous positive airway pressure, which is constantly efficacious but constraining. Central sleep apnoea syndromes are rare, less clearly defined and more difficult to treat.

Adult↗
PubMed1986

Inter- and intrahemispheric processing of letter stimuli by dyslexic children and normal readers.

Manual reaction-times and errors to single letter stimuli presented ipsilaterally (intrahemispherically) or contralaterally (interhemispherically) to the responding hand were compared for dyslexic children and normal readers aged 8 to 13 years. Dyslexic children were significantly slower than normal readers across four field-hand conditions, but for the dyslexic group, reaction times were not discrepantly longer nor were errors more frequent in the contralateral condition, contrary to the hypothesis of impaired interhemispheric processing in that group. Unlike normals, dyslexic children made more errors in the right visual field-right hand condition. These results suggest that cortical and/or subcortical information processing is slower in dyslexics, but that neither the rate nor the accuracy of information transfer between the hemispheres is specifically abnormal. In addition, some defect within the left hemisphere of dyslexics for processing linguistic stimuli is indicated.

Adolescent↗
PubMed1985

Motor proficiency in dyslexic children with and without attentional disorders.

Motor proficiency, in terms of speed, rhythm and absence of overflow, has previously been shown to distinguish nonlearning disabled hyperactive boys from matched controls. Accepted screening methods for selecting children with dyslexia do not include assessments of hyperactivity or other attentional deficits. Dyslexic children selected in this customary manner were compared with an otherwise matched group that had been screened for attentional disorders, on a series of repetitive and alternating movements of the fingers, hands, and feet. The screened dyslexic group performed more rapidly on five of six movements and had fewer qualitative signs of dysrhythmia or overflow.

Attention Deficit Disorder with Hyperactivity↗
PubMed1985

Matrix isolation of free radicals from carbohydrates. II. Reactions of H. with glucose and derivatives in acidic glasses.

Photolytically produced H.-atoms in 6 mol dm-3 H2SO4/H2O glasses trapped at 77 K react upon annealing to 130 K with dissolved carbohydrates to form carbon-located free radicals by abstraction of carbon-bound protons. Analysis of electron spin resonance (e.s.r.) spectra at various annealing stages from alpha- and beta-D-glucose together with 6,6-d2-D-glucose, 6-deoxy-D-glucose, 2-deoxy-D-glucose, glucose-1-phosphate, D-xylose, D-allose and D-mannose indicates radical formation at all possible carbon sites with a strong preference for C1 and a somewhat enhanced contribution of C4 over the statistical expectation. The corresponding component spectra are analysed either by spectra isolation or simulation and their parameters are given. Intramolecular radical transformation at temperatures of 140-160 K is explained by acid-catalysed H2O-elimination. The findings are discussed in relation to the radiation-chemistry of aqueous glucose solutions. We thus show that the system of photolyzed Fe2+ in acidic glasses at low temperatures containing 10 mmol dm-3 carbohydrate is suitable for studying H(D.)-reactions by means of e.s.r. spectroscopy. Unlike previously used glasses containing carbohydrates, contributions of oxidation and reduction by direct effects or mixtures of direct and indirect effects and phase-effects due to incomplete glass formation are avoided.

Carbohydrates↗
PubMed1985

Flow-volume curve abnormalities and obstructive sleep apnea syndrome.

Recent reports have suggested that flow volume curve abnormalities may be of interest in the diagnosis of obstructive sleep apnea syndromes by showing either extrathoracic airway obstruction (ratio of expiratory flow to inspiratory flow at 50 percent of forced vital capacity [FEF50/FIF50] exceeding 1) or upper airway fluttering (indicated by a sawtooth aspect on the mid-half of the inspiratory part of the curve) or both. In our study, 57 patients referred for a suspected sleep apnea syndrome (SAS) underwent conventional spirometry, assessment of flow-volume curves, ENT examination, and polysomnography. Thirty patients had an obstructive SAS, four patients a central SAS, and 23 patients no SAS. Signs of upper airway fluttering (the sawtooth sign) were present in 61 percent of the patients with obstructive SAS and in 46 percent of the patients without obstructive SAS (central SAS or no SAS). Signs of extrathoracic upper airway obstruction (FEF50/FIF50 greater than 1) were present in 67 percent of the patients with obstructive SAS and in 71 percent of the patients without obstructive SAS. These results suggest that upper airway abnormalities, as reflected by abnormal flow volume curves, are not always associated with obstructive SAS; they favor the hypothesis of a central component in the mechanism of upper airway occlusion during sleep.

Female↗
PubMed1985

Inter- and intrahemispheric processing of visual and auditory stimuli by dyslexic children and normal readers.

Four experiments are presented in which manual reaction times to simple visual or auditory stimuli are compared for bilateral, ipsilateral, and contralateral presentations in normal and dyslexic children at three age levels: 8-9, 10-11, and 12-13 years. While bilateral presentations yielded faster reaction times, there were no consistent right-left differences nor consistent superiority of intra- versus interhemispheric reaction times in either of the experimental groups. The results failed to support the hypothesis of slower interhemispheric (cross-callosal) processing in dyslexic children.

Adolescent↗
PubMed1985

[Sleep and nocturnal desaturation of patients with chronic obstructive bronchopneumopathies. Effects of almitrine bismesylate administered orally].

In order to verify the effect of almitrine bismesylate on episodes of nocturnal oxygen desaturation, 10 patients suffering from chronic obstructive pulmonary disease had polygraphic EEG night sleep recordings with simultaneous measurement of O2 saturation. The subjects presented during nocturnal sleep a quantity of desaturation of at least 2,400 sec. X p. cent (this quantity being represented by the surface of the SaO2 curve under the desaturation level defined as the waking SaO2 less 4 p. cent) and had been included in a matched experimental protocol, double blind, almitrine bismesylate versus placebo. After administration of either placebo or almitrine bismesylate for 14 days (100 mg per day in two doses) a control night sleep recording was performed. The effect of treatment was assessed using an analysis of variance for 2 or 3 factors, completed by a Student t test in case of significant interaction between the factors. It appears that almitrine bismesylate produces: a non significant decrease in total sleep, slow wave sleep and REM sleep time; a significantly earlier awakening (p less than 0.05); a significant reduction of the total duration of desaturation episodes (p less than 0.05) without any correlation with the variations of total sleep time; a non significant decrease in the quantity of desaturation; a significant increase in PaO2 (p less than 0.001) and in SaO2 (p less than 0.01) measured two hours after the awakening. However there was no evidence of any significant change in mean SaO2 and lowest SaO2 during the night. Finally the variability of the effect of almitrine bismesylate during day or night time remains unexplained.

Administration, Oral↗
PubMed1985

Breathing during sleep in normal subjects.

Despite considerable data, little is certain about changes in breathing during sleep, let alone possible mechanisms for these changes. This article reviews methodologic problems, including the definition of the normal subject, the definition of the sleep state, and the effects of instrumentation, and discusses data on respiration during REM and NREM sleep in normal humans. Although the evidence is incomplete, respiration during sleep appears fragile, prone to instability, to upper airway obstruction, to hypoventilation, and to ventilation-perfusion mismatch, jeopardizing the homeostatic function of CO2 output and O2 uptake.

Adolescent↗
PubMed1984

[Continuous positive pressure in the treatment of sleep apnea syndromes].

Continuous positive airway pressure as a long-term home treatment for sleep apnea syndromes would seem to present irreconcilable requirements; it must be simple and comfortable to use during sleep and it must be relatively inexpensive. The device described in this paper includes a compressor, an individually molded nose-mask and a water column. Improvements are still in progress, but, as it stands, it enables sleep apnea patients to be successfully treated at home.

Humans↗