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Biomedical subjects

R Ley

Publications and source records attributed to R Ley.

At least 37 records · Page 2Linked to original sources
PubMed1992

A hyperventilation interpretation of the termination of panic attacks: a reply to van den Hout, de Jong, Zandbergen and Merckelbach.

This paper summarizes the brief publication history of how a hyperventilatory positive-feed-back-loop theory of panic attacks explains the termination of panic attacks. A cautionary note is suggested when interpreting generalizations pertaining to panic attacks in panic-disorder sufferers in the everyday world made from laboratory findings based on healthy asymptomatic subjects.

Arousal↗
PubMed1991

Ventilatory control of heart rate during inhalation of 5% CO2 and types of panic attacks.

Differences in the magnitude of increases in heart rate during prolonged inhalation of 5% CO2 range from a mean of 25 b/min for a group of eight panic-disorder patients who panicked (Woods, Charney, Goodman, & Heninger, 1988. Archives of General Psychiatry, 45, 43-52) to zero b/min for 16 patients, eight of whom panicked (Craske & Barlow, 1990. Journal of Abnormal Psychology, 99, 302-307). What accounts for this disparity? The present paper describes how heart rate can be increased by means of voluntary overbreathing during prolonged inhalation of 5% CO2 in air. This suggests that differences in the degree of overbreathing may explain differences in the magnitude of increases in heart rate during inhalation of 5% CO2. An explanation is also offered for the curious finding that some patients experience "panic attacks" with zero increase in heart rate. Evidence suggests that this is likely to happen in cognitively based panic attacks, in contrast to hyperventilatory attacks or anticipatory attacks.

Arousal↗
PubMed1991

The efficacy of breathing retraining and the centrality of hyperventilation in panic disorder: a reinterpretation of experimental findings.

The present paper addresses de Ruiter, Rijken, Garssen, and Kraaimaat's (Behaviour Research and Therapy, 27, 647-655, 1989) interpretation of data pertaining to the efficacy of breathing retraining in the treatment of panic disorder. The proffered reinterpretation of these data makes it clear that breathing retraining led to a significant reduction in the frequency of panic attacks. These findings thus lend additional support to the central role of hyperventilation in primary panic attacks.

Anxiety Disorders↗
PubMed1989

Dyspneic-fear and catastrophic cognitions in hyperventilatory panic attacks.

The tenability of cognitive explanations of the experience of fear during panic attacks (viz. Ley's misattribution-of-symptoms hypothesis and Beck's and Clark's catastrophic-misinterpretation-of-symptoms hypotheses) is seriously questioned by findings from three independent lines of research: (a) Wolpe and Rowan's observation that catastrophic cognitions follow fear, (b) Rachman, Levitt and Lopatka's reports of panic attacks without fearful cognitions, and (c) reports of panic attacks during sleep occurring predominately during non-dreaming stages of sleep. Recognition of these findings led Ley to reject his misattribution-of-symptoms hypothesis in favor of an innate emotional-respiratory-response explanation. The revised hyperventilation theory now maintains that fear experienced during a hyperventilatory panic attack is caused by severe dyspnea in the context of little or no perceived control over the causes of the dyspnea (i.e. dyspneic-fear). Cognitions during panic attacks are discussed in terms of the cognitive deficit that results from the cerebral hypoxia produced by hyperventilation. Implications for theory and treatment are discussed.

Arousal↗
PubMed1988

Panic attacks during sleep: a hyperventilation-probability model.

Panic attacks during sleep are analysed in terms of a hyperventilation theory of panic disorder. The theory assumes that panic attacks during sleep are a manifestation of severe chronic hyperventilation, a dysfunctional state in which renal compensation has led to a relatively steady state of diminished bicarbonate. Reductions in respiration during deep non-REM sleep lead to respiratory acidosis which triggers hyperventilatory hypocapnea and subsequent panic. A probability model designed to predict when during sleep panic attacks are likely to occur is supported by relevant data from studies of sleep and panic attacks. Implications for treatment are discussed.

Carbon Dioxide↗
PubMed1988

Panic attacks during relaxation and relaxation-induced anxiety: a hyperventilation interpretation.

This paper explains how a hyperventilation theory of panic disorder accounts for panic attacks during relaxation and relaxation-induced anxiety. The explanation is based on the observation that chronic hyperventilators maintain a steady state of low pCO2 (arterial carbon dioxide tension) and are, therefore, sensitive to relatively small increases in ventilation when metabolism is low and to relatively sudden reductions in metabolism when ventilation is relatively constant. Thus, if minute volume of air breathed remains constant while the metabolic production of CO2 decreases, as in the case of one who sits down or lies down to relax, respiratory hypocapnea may increase in intensity until it produces the familiar sensations which mark the panic attack. Data from relevant studies of panic attacks during relaxation support the hyperventilation interpretation.

Anxiety Disorders↗
PubMed1987

Panic disorder and agoraphobia: fear of fear or fear of the symptoms produced by hyperventilation?

Two versions of the fear-of-fear hypothesis of panic disorder are discussed. The fear-of-the-somatic-effects-of-fear version, which is distinguished from the classical conditioning version, is compared with the hyperventilation theory of panic disorder and agoraphobia. The fear-of-the-somatic-effects-of-fear hypothesis is criticized on the basis of its inability to explain adequately (a) the initiation of panic attacks, (b) the growth in intensity of panic attacks, and (c) the termination of panic attacks. The tenability of the hyperventilation theory is supported by evidence from programs of treatment derived from the basic assumptions of the theory.

Agoraphobia↗
PubMed1983

[Aspergillus infection of severe burns].

Aspergillus, which has a saprophytic life, is an opportunistic fungus and manifests his pathogenicity when a weakened state of the host facilitates its development. The conditions are particularly favorable in severely burned patients like the 54-year-old woman presented here. The criteria of pathogenicity of this opportunistic fungus, the incidence of epidemiology and prognosis of this type of infection and the clinical signs that allow an early diagnosis are discussed here.

Air Microbiology↗
PubMed1981

Analysis of resynthesis tracts in repaired Escherichia coli deoxyribonucleic acid.

Excision repair of ultraviolet radiation-induced damage in a wild-type strain of Escherichia coli has been examined, using two methods for characterizing the resynthesis step of the repair process. Comparison of data obtained after both isopycnic analysis of repaired deoxyribonucleic acid and sedimentation velocity analysis of deoxyribonucleic acid after selective photolysis of bromouracil-containing repaired regions has shown that the repaired deoxyribonucleic acid molecules contain a semicontinuous distribution of sizes of repair tracts. Further analysis of our data suggests two major classes of repair patches, one abut 20 to 40 nucleotides in length, and the other containing 1,600 to 2,000 nucleotides. Under the conditions employed, approximately 2 to 10% of the fully repaired regions are long repair patches.

Centrifugation, Isopycnic↗
PubMed1978

Compression treatment of hypertrophic scars in burned children.

The formation of hypertrophic scars is common following healing of the burn wound, particularly in children. The control of scar formation is an important part of overall treatment in these cases and this paper describes a newer method that applies compression to the burn scar in an attempt to improve the ultimate appearance. The 35 patients treated by this method included some with partial-thickness and others with full-thickness burns. The results of treatment with compression garments were assessed at 6 months and at 12 months, using a grading system based on colour, consistency and thickness of the scar. The design of facial moulages and their use in compression of facial scars are dealt with. Overall there was a 75% to 80% improvement in the state of burn scars. The reasons for this improvement are discussed.

Adolescent↗
PubMed1975

[Digestive complications in patients with severe burns (author's transl)].

This is a report on 18 patients suffering digestive complications, among 593 burned patients treated during seven years. This clinical analysis mainly stresses the poorly understood intestinal ileus that occurs in such patients. The work includes an appraisal and synthesis of some data from the literature.

Adolescent↗