Increased prevalence of perennial allergic rhinitis in patients with obstructive sleep apnea

BACKGROUND

Impaired nasal breathing is a risk factor for obstructive sleep apnea syndrome (OSAS).

OBJECTIVES

The aim of this study was to determine whether atopy to perennial allergens and existence of perennial allergic rhinitis was a risk factor for OSAS.

METHODS

In a case-control study, we compared the proportions of OSAS patients with atopy to perennial allergens and perennial allergic rhinitis to the proportions in patients with chronic obstructive pulmonary disease (COPD). Seventy-two OSAS patients (mean age 60.7 years; 79.4% male) and 44 COPD patients (mean age 63.6 years; 88.6% male) were selected from a hospital outpatients' clinic in Switzerland. All patients completed a respiratory symptom questionnaire, performed spirometry and had a skin prick test for atopy.

RESULTS

OSAS patients were significantly heavier than COPD patients (BMI 32.4 +/- (SD) 6.6 vs. 29.2 +/- 6.6 kg/m2, p = 0.04) and had a better lung function than COPD patients (FEV1% predicted 91.3 +/- 19.2 vs. 51.6 +/- 18.9%, p < 0.001). Patients with OSAS were more likely to be sensitized to perennial allergens such as house dust mite (23.6 vs. 4.5%, p = 0.009) and dog (18 vs. 4.5%, p = 0.04) than the COPD patients. Perennial allergic rhinitis (having nose problems [nasal obstruction and/or runny nose and/or sneezing] all year and being atopic to at least one perennial allergen) was reported in 11% of OSAS patients but in only 2.3% of COPD patients (p = 0.15).

CONCLUSION

We conclude that subjects with OSAS may have an increased risk of being allergic to perennial allergens and suffer from perennial rhinitis. Awareness of this risk may have important consideration in the clinical situation.

Pulmonary rehabilitation in outpatients with asthma or chronic obstructive lung disease. A pilot study of a "modular" rehabilitation programme

STUDY/PRINCIPLES

Pulmonary rehabilitation programmes are often costly and dependent on the infrastructure of specialised centres. We developed a modular, outpatient-based rehabilitation programme, which is inexpensive and can be implemented in a variety of settings. The aim of this study was to determine the effects and feasibility of this programme.

METHODS

Thirteen patients with COPD and 7 patients with asthma were enrolled by their primary care physician because of dyspnoea. Initial assessment included cardiopulmonary exercise testing, six-minute walking distance, lung function testing and multiple questionnaires addressing dyspnoea, depression and quality of life issues. The training consisted of 36 sessions of high intensity training of 2 hours duration to improve exercise tolerance, including 30 minutes of stationary cycling at the anaerobic threshold. Another complete assessment was done on completion of the study at 3 months.

RESULTS

The six-minute walking distance improved significantly from 401 to 551 m (p < 0.0001). The maximal exercise capacity increased significantly from 85 W to 99 W (p < 0.001). The anaerobic threshold remained unchanged despite the high intensity training. There was a reduction of dyspnoea and an improvement of quality of life.

CONCLUSION

This study shows that our outpatient rehabilitation programme leads to a benefit in exercise tolerance and health related quality of life comparable to other programmes published in the literature. The rehabilitation programme was very well accepted among patients, primary care physicians and health insurers.

Pulmonary rehabilitation in outpatients with asthma or chronic obstructive lung disease. A pilot study of a "modular" rehabilitation programme

STUDY/PRINCIPLES

Pulmonary rehabilitation programmes are often costly and dependent on the infrastructure of specialised centres. We developed a modular, outpatient-based rehabilitation programme, which is inexpensive and can be implemented in a variety of settings. The aim of this study was to determine the effects and feasibility of this programme.

METHODS

Thirteen patients with COPD and 7 patients with asthma were enrolled by their primary care physician because of dyspnoea. Initial assessment included cardiopulmonary exercise testing, six-minute walking distance, lung function testing and multiple questionnaires addressing dyspnoea, depression and quality of life issues. The training consisted of 36 sessions of high intensity training of 2 hours duration to improve exercise tolerance, including 30 minutes of stationary cycling at the anaerobic threshold. Another complete assessment was done on completion of the study at 3 months.

RESULTS

The six-minute walking distance improved significantly from 401 to 551 m (p < 0.0001). The maximal exercise capacity increased significantly from 85 W to 99 W (p < 0.001). The anaerobic threshold remained unchanged despite the high intensity training. There was a reduction of dyspnoea and an improvement of quality of life.

CONCLUSION

This study shows that our outpatient rehabilitation programme leads to a benefit in exercise tolerance and health related quality of life comparable to other programmes published in the literature. The rehabilitation programme was very well accepted among patients, primary care physicians and health insurers.

Pattern separation and synchronization in spiking associative memories and visual areas

Scene analysis in the mammalian visual system, conceived as a distributed and parallel process, faces the so-called binding problem. As a possible solution, the temporal correlation hypothesis has been suggested and implemented in phase-coding models. We propose an alternative model that reproduces experimental findings of synchronized and desynchronized fast oscillations more closely. This model is based on technical considerations concerning improved pattern separation in associative memories on the one hand, and on known properties of the visual cortex on the other. It consists of two reciprocally connected areas, one corresponding to a peripheral visual area (P), the other a central association area (C). P implements the orientation-selective subsystem of the primary visual cortex, while C was modeled as an associative memory with connections formed by Hebbian learning of all assemblies corresponding to stimulus objects. Spiking neurons including habituation and correlated noise were incorporated as well as realistic synaptic delays. Three learned stimuli were presented simultaneously and correlation analysis was performed on spike recordings. Generally, we found two states of activity: (i) relatively slow and unordered oscillations at about 20-25 Hz, synchronized only within small regions; and (ii) faster and more precise oscillations around 50-60 Hz, synchronized over the whole simulated area. The neuron groups representing one stimulus tended to be simultaneously in either the slow or the fast state. At each particular time, only one assembly was found to be in the fast state. Activation of the three assemblies switched on a time scale of 100 ms. This can be interpreted as self-generated attention switching. On the time scale corresponding to gamma oscillations, cross correlations between local neuron groups were either modulated or flat. Modulated correlograms resulted if the groups coded features corresponding to a common object. Otherwise, the correlograms remained flat. This behavior is in agreement with experimental results, while phase-code models would generally predict modulated correlations also in the case of different objects. Furthermore, we derive a technical version from our biological associative memory model that accomplishes fast pattern separation parallel in O(log2 n) steps for n neurons and sparse coding.

Survey of children supported by long-term mechanical ventilation in Switzerland

OBJECTIVE

The aim of the present study was to identify the number of children, from birth to 16 years of age, on long-term mechanical ventilation in Switzerland, and to establish their current location, underlying diagnoses and ventilatory needs.

METHODS

Postal questionnaires were sent to all chest physicians (pulmonologists), intensive care specialists, neurologists, national health care organisations, rehabilitation services and ventilator suppliers known or thought to be involved in paediatric long-term ventilation in Switzerland.

RESULTS

Detailed information was obtained on 32 children from 7 centers. Underlying disorders included congenital central hypoventilation syndrome (CCHS, 41%), neuromuscular disorders (41%), spinal cord injury (6%), craniofacial anomalies (6%) and others (6%). 10 children received positive pressure ventilation by tracheostomy and 19 children by nasal mask. Two children were ventilated by phrenic nerve pacing and one child with the help of a pneumatic belt. Children with CCHS were almost equally divided into nasal mask and tracheostomy users. Ventilation for 16-24 hours a day was necessary in 5 children, exclusively during sleep in 24 children and only episodically in 3 children. All but 2 children were cared for at home. The majority of families received home care support. The most common reasons for readmission into hospital were regular follow-up examinations and respiratory tract infections. The children were mainly admitted to paediatric intensive care units.

CONCLUSIONS

There are few ventilator-supported children in Switzerland and most of them are cared for at home. Nevertheless, there is a need to establish a system for continuing data collection in this particular patient population to assess outcome and quality of home care support and to follow incidence trends.

Survey of children supported by long-term mechanical ventilation in Switzerland

OBJECTIVE

The aim of the present study was to identify the number of children, from birth to 16 years of age, on long-term mechanical ventilation in Switzerland, and to establish their current location, underlying diagnoses and ventilatory needs.

METHODS

Postal questionnaires were sent to all chest physicians (pulmonologists), intensive care specialists, neurologists, national health care organisations, rehabilitation services and ventilator suppliers known or thought to be involved in paediatric long-term ventilation in Switzerland.

RESULTS

Detailed information was obtained on 32 children from 7 centers. Underlying disorders included congenital central hypoventilation syndrome (CCHS, 41%), neuromuscular disorders (41%), spinal cord injury (6%), craniofacial anomalies (6%) and others (6%). 10 children received positive pressure ventilation by tracheostomy and 19 children by nasal mask. Two children were ventilated by phrenic nerve pacing and one child with the help of a pneumatic belt. Children with CCHS were almost equally divided into nasal mask and tracheostomy users. Ventilation for 16-24 hours a day was necessary in 5 children, exclusively during sleep in 24 children and only episodically in 3 children. All but 2 children were cared for at home. The majority of families received home care support. The most common reasons for readmission into hospital were regular follow-up examinations and respiratory tract infections. The children were mainly admitted to paediatric intensive care units.

CONCLUSIONS

There are few ventilator-supported children in Switzerland and most of them are cared for at home. Nevertheless, there is a need to establish a system for continuing data collection in this particular patient population to assess outcome and quality of home care support and to follow incidence trends.

Adverse reactions to peak flow monitoring. Report of 5 patients

Five patients with adverse reactions to peak flow monitoring are presented: 2 patients had herniation of abdominal content, while the others presented with vasovagal syncope, minor depression and neurotic preoccupation with peak flow values, respectively. As a result, 3 of the 5 patients became noncompliant. For nonpsychological somatic adverse reactions, we calculated an incidence of 1.1 cases/1,000 patients started on peak flow monitoring. Adverse reactions with a psychological background may be more frequent. Clinicians should bear in mind that patients noncompliant with peak flow monitoring may have discontinued because of adverse reactions.

Major accidents related to manure: A case series from Switzerland

Manure is an important element in the farm economy, but its storage and use are associated with risks. Major accidents related to manure exposure were analyzed using technical and demographic criteria. Of the 61 accidents, 44 were due to inhalation of manure gas, 11 involved falls into manure containers, and six were methane explosions. There were 49 fatalities, including 12 (24%) in which persons attempting to rescue primary victims died. 37 persons survived gas poisoning. Small children usually fell into the manure and drowned. There were 15 successful rescues and four cases in which primary victims saved themselves. The main danger is that of gradual or sudden manure gas intoxication, which is often fatal. However, almost a third of the accidents were due to falls into manure containers or manure gas explosions. Accidents in which victims of gas poisoning regained consciousness and saved themselves are also reported. Analysis of the accident circumstances confirms the importance of meticulous observation of existing safety guidelines with respect to both structural design and working practices. Specific measures at the scene can substantially increase the chances for survival of both primary victims and would-be rescuers.

[Tuberculin testing of hospital personnel: large investment with little impact]

Guidelines for the control and prevention of nosocomial tuberculosis include recommendations for surveillance of hospital employees with tuberculin skin tests (TST). We analysed a 2 1/2-year period of tuberculin skin testing at Kantonsspital St. Gallen, an 850-bed hospital in eastern Switzerland with 2000 employees and 21,000 admissions yearly. Tuberculosis cases among employees are reported for a 10-year period. TST were performed on engagement, if no recent positive result was available. A new TST was read in 717 (58%) of 1241 persons starting employment during the study period. In 261 workers in contact with 23 sputum smear positive tuberculosis patients, 180 (69%) follow-up TST were performed. Of a total of 37 increases in TST, 20 (54%) were retrospectively attributed to other causes than a recent infection with M. tuberculosis (vaccination with BCG, booster phenomenon, doubts concerning the previous test result). Of the remaining 17 TST converters, 5 finally completed a full course of preventive chemotherapy. With a total workload of 547 hours for this result, half a year's working hours were necessary to prevent one case of active tuberculosis. Over a 10-year period, 4 out of 9 active tuberculosis cases in employees were likely to be nosocomially acquired, but none was diagnosed thanks to TST surveillance. We conclude that surveillance with TST is time consuming, but has little impact on the tuberculosis situation in hospital employees. Alternative strategies to this unsatisfactory system are discussed.

Manure-related accidents: the historical perspective

Liquid manure is an important element in modern intensive agriculture. However, its handling and storage present acute risks in the form of toxic or explosive gases and large storage containers, access to which is often inadequately secured. In recent years occupational medicine and accident prevention experts have begun the task of systematically identifying the sources of risk and formulating safety guidelines. The present paper, a byproduct of research into the epidemiology of manure-related accidents in eastern Switzerland, explores the history of this type of accident. The historical record shows that in centuries past such events were an urban rather than a rural phenomenon. The main sources of risk were the cesspits in which domestic, hospital and prison waste was collected, cemeteries and church crypts where the dead were laid to rest and even the holds of ships transporting cargos of dried excrement intended for use as agricultural fertiliser. Historical accounts indicate that then, as now, there was often inadequate awareness of the dangers of such installations, despite the many (often dramatic) contemporary reports of accidents and fatalities caused by failure to institute and observe basic safety rules.

Sleep-related laryngospasm

The term "sleep-related laryngospasm" refers to episodic, abrupt interruption of sleep accompanied by feelings of acute suffocation followed by stridor. The condition is included in the diagnostic and coding manual of the American Sleep Disorders Association (ASDA), but there are few references in the peer-reviewed literature. Our description of the distinct clinical picture associated with this condition is based on an analysis of the histories of a series of 10 patients. The patients and their families gave precise, uniform accounts of the dramatic attacks. Diagnostic work-up included pulmonary and gastroenterological assessment. All patients reported sudden awakening from sleep due to feelings of acute suffocation, accompanied by intense fear. Apnoea lasting 5-45 s was followed by stridor. Breathing returned to normal within minutes. Patients were left exhausted by the attacks. Nine of our 10 patients had evidence of gastro-oesophageal reflux and six responded to antireflux therapy. We conclude that the nocturnal choking attacks (and the occasional daytime attacks experienced by some of the patients) are caused by laryngospasm. The pathogenesis of the apparent underlying laryngeal irritability is unknown. The condition may be related to a gastro-oesophageal reflux.

[Disseminated mycobacteriosis with M. kansasii in a case of AIDS without HIV infection]

M. kansasii is an environmental Mycobacterium that causes disease mainly in patients with local or systemic immunodeficiency. We present a case with disseminated M. kansasii infection which led to a severe febrile illness lasting for 9 months. The patient had a combined acquired immunodeficiency syndrome (AIDS) which included CD4+ and CD8+ T-lymphocytopenia, monocytopenia and a deficiency in the IgG subclasses 2 and 4. HIV testing was repeatedly negative. In the published literature only 4 of 10 similar patients (this patient included) survived a disseminated M. kansasii infection. Eleven years after the disseminated infection with M. kansasii a second opportunistic infection, disseminated mollusca contagiosa and hyperparathyroidism, developed, and 14 years later the immunologic abnormalities persist.

Management 1997 of chronic obstructive pulmonary disease. Working Group of the Swiss Society of Pneumology

COPD is a disorder characterized by expiratory flow limitation that does not change markedly over periods of several months' observation. When the diagnosis is suspected, COPD patients should be submitted to full assessment and initiation of therapy. Initial assessment includes a complete history, a detailed physical examination, pulmonary function tests, a chest X-ray, and blood tests. Therapy of COPD aims at reducing symptoms, preventing exacerbations and preserving optimal lung function. Many COPD patients have a bronchospastic component and usually show some response to bronchodilator therapy. Anticholinergics, beta 2-agonists or theophylline are used as monotherapy or in combination. A subgroup of patients with COPD may benefit from oral long-term corticosteroid therapy. At prime diagnosis of COPD, a trial of oral steroid under optimal bronchodilator therapy is warranted in order to identify steroid responders early in the course of the disease. Stopping smoking is the most effective preventive measure and should be combined with complementary approaches such as eviction of environmental irritants, vaccines and prescription of antioxidants. Long-term oxygen therapy is beneficial in chronically hypoxemic patients. Respiratory rehabilitation uses a multidisciplinary approach aiming at decreasing dyspnea, increasing exercise tolerance and improving quality of life. Nocturnal home noninvasive mechanical ventilatory assistance can improve arterial blood gas tensions in patients with respiratory failure, but the long-term effect on survival is still under investigation. In selected patients, surgery (bullectomy, lung volume reduction, lung transplantation) may greatly improve pulmonary function.

Diffuse microvascular pulmonary thrombosis associated with primary antiphospholipid antibody syndrome

Thromboembolism is a well-known complication of the hypercoagulable state associated with antiphospholipid (aPL) antibodies. Acute respiratory failure (ARF) with diffuse pulmonary infiltrates has been reported in only a few patients with aPL antibodies. We describe a 49 year old patient with spiking fever, livedo reticularis, mild haemoptysis and ARF. Chest radiography revealed diffuse bilateral pulmonary infiltrates, and high resolution computed tomography (CT) revealed patchy distribution of areas of ground-glass attenuations. Pulmonary emboli were excluded with angiography. Lung biopsy revealed diffuse microvascular thrombosis, without capillaritis. High serum levels of anticardiolipin (aCL) antibodies were found. The patient's condition improved dramatically after intravenous infection of 1 g methylprednisolone on three consecutive days, followed by 50 mg prednisone orally. The rapid improvement following the administration of glucocorticosteroids suggests that anticardiolipin associated microvascular thrombosis, without inflammatory lesions, may depend on an interference with beta2-glycoprotein I (beta2=GPI) by anticardiolipin.

Accidents related to manure in eastern Switzerland: an epidemiological study

OBJECTIVES

Liquid manure systems and manure pits are major hazards in the agricultural workplace. The incidence of accidents related to manure is unknown. The objective of this study was to survey the liquid manure facilities of farms in eastern Switzerland and find the incidence of accidents related to manure in the region.

METHODS

Retrospective cohort study and cross sectional survey of 210 farms in eastern Switzerland.

RESULTS

The incidence of accidents related to manure was found to be 10.4/1000 person-years. Most accidents were categorised as minor--that is, had a benign outcome for the people involved or involved animals only. One in 33 of the farms surveyed was the scene of an accident related to manure each year.

CONCLUSIONS

The medical literature on accidents related to manure mostly reports accidents with catastrophic outcomes. This study shows that this type of accident is only the tip of the iceberg. Most of the accidents reported in this study belong to a category that has hitherto been un-noticed and unreported. The term "accident related to manure" covers a broad range of events, and those resulting in serious human illness or death represent only a small part of this spectrum. A wide variety of liquid manure systems were found on the farms surveyed. Very few liquid manure facilities conformed to published safety standards.

[Dust exposure, dust-induced lung diseases and respiratory protective measures in agriculture]

Epidemiologic studies indicate a high prevalence of respiratory diseases among the farming population. Many of these diseases are responsible for disability and death and there is a considerable impact on the economy and health cost expenditure. Respirable organic dust plays a major pathogenetic role. Part I of this review discusses the diseases and syndromes caused by organic dust: organic dust toxic syndrome; chronic bronchitis and chronic obstructive pulmonary disease; asthma; and hypersensitivity pneumonitis. Part II describes preventive measures for dust control. Besides technical aspects in the process of agriculture production, special emphasis is placed on personal protective equipment systems (face-masks and air-purifying respirators). Applications, advantages and disadvantages of these systems are discussed and critically compared.

Severe inflammatory upper airway stenosis in ulcerative colitis

Severe upper airway stenosis was diagnosed in a 23 year old woman who presented with hoarseness, cough and dyspnoea 8 yrs after initial diagnosis of ulcerative colitis. The respiratory symptoms worsened over the next few months, the patient eventually developing dysphagia and ultimately severe upper airway obstruction. The narrowest site was the glottis, which was severely stenosed by inflammatory swellings. Systemic corticosteroids led to rapid clinical improvement and restoration of normal airway patency within a few months. Ulcerative colitis is frequently associated with extraintestinal inflammatory manifestations. In the respiratory tract these usually take the form of chronic bronchitis, which occasionally develops into bronchiectasis. This case confirms that the inflammation can also involve the larynx and large airways.

Simultaneous bilateral spontaneous pneumothorax

We describe 12 patients with simultaneous bilateral spontaneous pneumothorax (SBSP). They represent 4 percent of patients with spontaneous pneumothorax seen at our hospital from 1971 to 1990. Five of the 12 had no underlying lung disease. In the seven remaining patients, SBSP was secondary to histiocytosis X, lymphangioleiomyomatosis, osteogenic sarcoma with pleural and pulmonary metastases, Hodgkin's disease, mesothelioma, cystic fibrosis, or miliary tuberculosis. Nineteen of the 56 patients with SBSP (34 percent) described in the literature (this series included) had pulmonary disease related to disorders of cells of mesenchymal origin. Emphysema and bullous lung disease were not associated with SBSP. Long-term prognosis was a function of pulmonary status. Four of the patients described herein died during the period reviewed. All suffered from severe underlying disease. In no case was SBSP the main cause of death. With timely treatment, the short-term prognosis is benign even for patients with underlying lung disease. Surgical pleurectomy should be attempted early, especially in SBSP secondary to underlying lung disease.

[Peak flow profile and expert testimony. The significance of peakflow self assessment for pneumological expert testimony]

Quantitative assessment of pulmonary obstructive diseases, such as asthma, may be difficult because of variability of obstruction. This is particularly true with regard to expert evidence pulmonary physicians deliver to insurances. Severity of obstruction, degree of impairment by an obstructive ventilatory defect, and temporal relationship of bronchial obstruction to exposure, may not be detected by physiological measurements in the pulmonary function laboratory. Much of the expert's opinion on these matters will depend on the credibility he assigns to the insured individual. The insured individual, in the other hand, has no other proof available than the description of his complaints, which puts him at a disadvantage. Serial peak flow measurements can be instrumental in clarifying such issues. They add an objective dimension to the case history. Six cases in which expert evidence was commissioned by insurances are described in detail, to exemplify how the thinking of the experts was modified by peak flow profiles. The greater usefulness of serial peak flow measurements in occupational asthma is emphasized and problems that may arise with peak flow measurements are discussed.

[Randomized and controlled single-case study--a scientific method for individual and difficult therapy decisions in clinical practice exemplified with methotrexate use in asthma]

For various reasons, optimal individual therapies cannot always be derived from monitored, large-scale random studies. This applies particularly to delicate decisions on the treatment of chronically ill patients. In such situations, random, controlled and "double-blind" individual case studies with "cross-over" can be a solution. The procedure is adjusted to suit the individual patient. In many two-part treatment phases, the patient receives the active medication and an alternative/placebo. The sequence is adapted to the randomization. Neither patient nor doctor knows what the preparations are. The aims of the study are primarily oriented towards the wellbeing of the individual patient. The problems of individual optimization of therapy in practice are presented, as are the individual case study methods. Their potential application and limits and their value are discussed and illustrated by means of an actual case study.

[Home mechanical ventilation in Switzerland in 1990. Future developments]

Home mechanical ventilation (HMV) was initiated in polio centers in the mid-50s (iron lung). Ten years ago, chronic respiratory insufficiency patients began to be treated with positive pressure ventilation via tracheostomy tube. Survival of kyphoscoliotic and myopathic patients was impressive in uncontrolled studies. Today it appears that similar results may be obtained with a new non-invasive technique, nasal mechanical ventilation. The present situation of HMV in Switzerland (number of patients and their location) and the results of this treatment are described. In addition, we report on a short series of 24 Swiss patients collected in 4 centers. We show that HMV is possible in Switzerland and that the results in survival and quality of life are excellent, provided that the indications for this technique are consistent with the recommendations in the literature.

[Home ventilatory support--retrospective view and perspectives]

Mechanical home ventilation is a child of this centuries polio epidemics. The tank respirator, or iron lung, signaled the beginning of the new era. Improved techniques like positive pressure ventilation via tracheostoma followed soon. Hypoventilation syndromes of various origin are more and more encountered thanks to better detection methods. They benefit from a new, efficient and noninvasive technique, the positive pressure ventilation via nasal mask.

[Amborum Special F and ASFO--2 glucocorticoid-containing herbal remedies]

Amborum Special F and ASFO are two names of a herbal remedy which is adulterated with the glucocorticoid betamethasone. Patients with asthma, rheumatic and chronic diseases import the drug direct from Burbank, California, USA. Its impressive antiasthmatic effect is reported in two patients. While under therapy the first patient developed Cushing's syndrome and the second showed suppression of adrenal cortisol production. The manufacturer, who claims that the drug contains no "western medicine" and in particular no cortisone, is unscrupulous enough to recommend it for children under two years of age. We have observed that a marked glucocorticoid effect and marked glucocorticoid side effects are achieved with small doses of betamethasone. A review of the literature and the two cases reported here suggest that the equivalence doses given in textbooks and tables of glucocorticoid equipotency are incorrect for betamethasone. Betamethasone is a more potent glucocorticoid than hitherto reported.

[Self-monitoring of airway obstruction using the peak flowmeter]

Daily peak flow measurements provide an accurate and objective assessment of airway obstruction. The peak flow profile offers a rational basis for antiobstructive treatment. Success and failure of treatment are visualized, as are the asymptomatic beginning of an asthmatic attack, an allergen exposure or an exercise-induced obstruction. Compliance improves, and self-monitoring seems to increase patient comfort. A considerable amount of knowledge about the dynamics of airway obstruction is conveyed to the physician, and this works very much to the benefit of his patient.

[Oculopharyngeal muscular dystrophy]

A family from eastern Switzerland with oculopharyngeal muscle dystrophy is described. The history shows seven affected persons in three generations. The inheritance pattern is autosomal dominant with complete penetrance. Bilateral ptosis and dysphagia, the hallmarks of the disorder, appear in the fourth decade and progess slowly. The late stage is characterized by ptosis, causing reclination of the head and marked upright posture. Dysphagia may be disabling, causing starvation, or, as in the index case, death by aspiration pneumonia. Surgical procedures are available to correct the ptosis and alleviate dysphagia.

Oxidant- and lipid-induced pulmonary vasoconstriction mediated by arachidonic acid metabolites

In experiments using isolated rabbit lungs perfused with Krebs-Henseleit buffer in a nonrecirculating manner, we found that administration of an organic peroxide, tert-butyl hydroperoxide (t-bu-OOH), or Intralipid, an esterified mixture of unsaturated fatty acids, caused a marked vasopressor response which was associated with increased levels of thromboxane in the effluent perfusate. The vasopressor response to t-bu-OOH was greater in the lungs of vitamin E-deficient animals, and this could be correlated with an attenuated ability to increase prostacyclin production in these lungs. Conversely, administration of Intralipid to normal lungs caused marked increases in prostacyclin and a smaller pressor response. The magnitude of the pressor response was strongly correlated with the ratio of thromboxane B2 to the prostacyclin metabolite. No release of these mediators was associated with pulmonary vasoconstriction caused by administration of angiotensin II. The pressor response could be completely blocked by administration of indomethacin. We propose that this activation of the cyclooxygenase pathway of arachidonic acid metabolism may be important in the pathophysiology of oxidant lung damage.

Effect of hypoxia and CO on a cytochrome P-450-mediated reaction in rabbit lungs

Evidence indicates that the diffusion of O2 and CO in tissue may be facilitated by a carrier molecule having a P50 that approximates tissue O2 partial pressure (PO2; 1-15 Torr) and a much higher affinity for CO than for O2. To determine whether cytochrome P-450 in lung satisfies these criteria, we measured the effect of hypoxia and of CO on the rate of metabolism of the cytochrome P-450 mediated O-demethylation of p-nitroanisole in isolated perfused rabbit lungs. Metabolism was inhibited by 50% of a control at an estimated tissue PO2 fo 4 Torr (5.5 microM). When inspired CO2 was kept at 200 Torr and inspired CO partial pressure (PCO) varied an estimated tissue PCO/PO2 ratio of 0.025 reduced the reaction rate by 50% of control, but some metabolism persisted at PCO/PO2 ratios larger than one. The relationship between reaction rate and PCO/PO2 ratio could not be fit by a single value for Haldane constant for M (CO affinity/O2 affinity) but could be described with a two-component model in which metabolism was equally divided between a high-affinity cytochrome (M = 200) and a low-affinity cytochrome (M = 2). These findings suggest that cytochrome P-450 could act as a carrier for O2 and CO in tissue with low PO2's.