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Biomedical subjects

H Worth

Publications and source records attributed to H Worth.

At least 19 recordsLinked to original sources
PubMed1992

Formoterol, fenoterol, and salbutamol as partial agonists for relaxation of maximally contracted guinea pig tracheae: comparison of relaxation with receptor binding.

In severe asthma attacks beta 2-sympathomimetics lose part of their therapeutic efficiency. To elucidate this loss of efficiency in an experimental model we compared the relaxant potency of salbutamol (SAL), fenoterol (FEN), formoterol (FOR), and (-)-isoprenaline (ISO) in guinea pig tracheae partially and maximally precontracted by 0.1 and 60 mumol/L carbachol, respectively. In partially precontracted tracheae the beta 2-sympathomimetics exerted maximum relaxation in comparison with ISO and low EC50S (nmol/L) for relaxation (SAL, 20; FEN, 5.6; FOR, 0.28; and ISO, 2.5). In maximally precontracted tracheae, however, the beta 2-sympathomimetics were only partial agonists for relaxation with reduced intrinsic activities (%) in comparison to ISO (SAL, 59%; FEN, 61%; FOR, 76%) and significantly increased EC50S (nmol/L) for relaxation (SAL, 130; FEN, 57; FOR, 3.0; ISO, 37). To investigate if the high relaxant potency of FOR is correlated with a higher binding affinity and/or a higher intrinsic activity for adenylate cyclase stimulation than for FEN and SAL, we performed experiments in receptor membranes from guinea pig lung. Binding competition of SAL, FEN, and FOR with [3H]ICI 118,551 for lung beta 2-adrenoceptors yielded dissociation constants (KD) of 320 (SAL), 120 (FEN), and 7.6 (FOR) nmol/L, which exhibited the same ranking as EC50S for relaxation. Concentrations of SAL, FEN, and FOR equivalent to 100 KD of the respective dissociation constants stimulated beta 2-adrenoceptor-coupled adenylate cyclase with different intrinsic activities (%) incomparison to ISO (SAL, 61%; FEN, 63%; FOR, 89%) matching intrinsic activities for relaxation. From these experiments it may be concluded that FOR might improve drug therapy of severe asthma not only due to its long mode of action discovered in clinical studies but also due to its high intrinsic activity and receptor affinity.

Adenylyl Cyclases↗
PubMed1992

The power-duration product--evaluation of a new reference system for cardiopulmonary exercise testing.

The aim of this study was to assess the discriminatory power of the new reference system, power-duration product (PDP), for the analysis of haemodynamic and metabolic variables derived from cardiopulmonary exercise tests. The PDP was calculated as the cumulative index of the product of power (W) times the duration (minutes) of each individual exercise step. The study comprised 30 healthy male volunteers, who were classified into three groups with respect to their regular physical activity: 10 untrained medical students (students), 10 sprinters and long-jumpers (athletes) and 10 endurance athletes performing triathlon (triathletes). Twenty metabolic and haemodynamic variables were recorded throughout exhaustion-limited cycling ergometry. The data were analysed with respect to five reference systems (heart rate, relative and absolute oxygen consumption/body surface area, power, and PDP). A total of 14 differences between modified time courses of haemodynamic and metabolic variables in the three groups of volunteers were observed by reference to PDP, 12 by reference to relative oxygen consumption/body surface area, 11 by reference to heart rate, 8 by reference to absolute oxygen consumption/body surface area, and 7 by reference to power. When using PDP as the reference, the time courses of 8 parameters differed significantly between students and triathletes, 5 between students and athletes, and 1 between athletes and triathletes. In addition to its discriminatory superiority for the comparison of different groups characterized by different cardiopulmonary training and endurance, it was found that PDP permitted a better characterization of the individually performed exercise than the consideration of power per se.

Adolescent↗
PubMed1992

[Negative cortisone attitude in patients with bronchial asthma].

Patients with bronchial asthma often exhibit irrational fears of cortisone medication beyond justified worries about side-effects. A negative cortisone image, which means overemphasizing the damaging and threatening aspects of cortisone, often underlies non-compliant illness behaviour. In the present study, cortisone image was investigated in 54 patients with bronchial asthma before and after participation in the Düsseldorf Asthma treatment and teaching programme (ATTP) and one year later. By participating in ATTP, a significant reduction of the negative cortisone image and thus a more realistic view of cortisone could be achieved in most patients. This effect was also evident at the follow-up examination one year later. On the other hand, persistence of a negative cortisone image in a subgroup of patients turned out to be a potent predictor of later non-compliant illness behaviour. Psychological implications of a persistent negative cortisone image are discussed.

Adult↗
PubMed1992

[Affective-cognitive coping with attacks and illness behavior in patients with bronchial asthma].

The purpose of this study was to investigate attack-related cognitive coping styles in 80 patients with bronchial asthma and to relate them to outcome parameters of illness behaviour. All patients had participated in a 5-day-lasting asthma treatment and teaching programme (ATTP). Outcome variables to be predicted were: The number of days in hospital due to asthma during the year following the training programme and the patients' adherence to the recommendations of the programme one year later. Independent predictor variables were: pre-training attack frequency, hospitalization due to asthma, medication intensity, pulmonary function, asthma symptom anxiety, trait anxiety and attack-related cognitive coping styles. Multiple regression analyses show the importance of a "minimizing/self-confident" coping style in predicting days in hospital, while a "diverting" style predicts best a poor management of attacks in patients on oral steroids.

Adaptation, Psychological↗
PubMed1991

Evaluation of a structured treatment and teaching programme on asthma.

The objective of this study was to evaluate a structured treatment and teaching programme for adult patients with moderate to severe asthma. The design consisted of a prospective, before-after trial: the same consecutive patients were studied before and after intervention with observation periods 1 year before and 1 year after intervention. The investigation took place within a tertiary care centre (university hospital). A total of 142 consecutive patients were referred for in-patient treatment of their asthma, of whom 132 (93%) patients participated in the follow-up examination. The intervention consisted of a structured 5-d in-patient treatment and teaching programme presented by a specialized nurse educator. The aim of the programme was for the patient to assume greater responsibility for disease management, including self-monitoring of peak expiratory flow and qualified self-adaptation of drug therapy. The main outcome measures were the frequency of severe asthma attacks, hospitalization, and absenteeism from work (data provided by health insurance companies), patients' compliance and management skills. During the year before and the year after the intervention 71% and 36%, respectively of patients had one or more severe asthma attacks (mean difference 35%, 95% CI: 25-45%, P less than 0.0001). The percentage of patients who were hospitalized because of asthma decreased from 39% to 22% (mean difference 17%, 95% CI: 7-27%, P less than 0.002). The percentage of employed patients (n = 67) who were absent from work because of asthma decreased from 60% to 43% (mean difference 17%, 95% CI: 4-30%, P less than 0.04). The patients' adherence to maintenance drug therapy and their management skills improved significantly. It was concluded that the participation of patients with moderate to severe asthma in a structured treatment and teaching programme resulted in a substantial reduction in asthma morbidity in the year following the intervention.

Absenteeism↗
PubMed1990

Patient education in asthmatic adults.

Despite the advances in the understanding of the pathogenic mechanisms, clinical assessment, and medical treatment of asthma, an increase of mortality and morbidity has been observed. It is clear from several studies, however, that this discrepancy may be at least partly due to serious defects, among asthmatic patients, in the ability to judge the severity of their asthma, and in the knowledge of medication and the correct action to take, when deterioration occurred. Therefore, to effectively manage asthma, structured education programs for adult asthmatics appear to be useful including information about the disease and the medication as well as training of self-management of airflow limitation by the patients. The evaluation of the course of the disease before and after the education revealed a reduction of severe attacks, hospitalizations, and days lost from work in trained asthmatics.

Adult↗
PubMed1990

Peripheral neuropathies in patients with chronic obstructive pulmonary disease: a multicenter prevalence study.

To investigate the prevalence and type of peripheral neuropathies (PNP) in patients with chronic obstructive pulmonary disease (COPD), we studied lung function and blood gases, clinical signs of PNP, and neurophysiological function in 151 patients with COPD without known risk factors for PNP. Mean (SD) age was 65 (10) years, mean arterial PO2 was 59 (9) mmHg, mean ratio of forced expiratory volume in the first second to vital capacity (FEV1.0/VC) was 42 (12%). Thirty patients (20%) had clinically detectable and 6 (4%) had subclinical PNP of mild degree. Fourteen (9%) of the patients with clinically detectable PNP had symptoms due to PNP. Prevalence of PNP increased with severity of hypoxemia (p less than 0.05) and was more pronounced in the lower than in the upper limbs. Age and the degree of hypoxemia were predictors to differentiate between COPD patients with and without PNP. Although the cause of PNP in COPD patients remains unknown, our observations suggest that chronic hypoxemia may contribute to PNP.

Adult↗
PubMed1990

Comparative analysis of arterial oxygen saturations during exercise by pulse oximetry, photometric measurements, and calculation procedures.

Pulse oximetry allows non-invasive monitoring of arterial oxygen saturation (SO2). To study the validity of pulse oximetry, comparative measurements were performed. During exhaustion limited exercise SO2-values measured by pulse oximetry (SO2puls), calculated SO2-values (algorithms of Kelman, Severinghaus, and Siggaard-Andersen--SO2calc), and as "golden standard" photometric measured SO2-values (SO2meas) were compared. Fourteen triathletes performed a stepwise cycling exercise test in the supine position. SO2calc was determined on the basis of capillary actual blood gas values. SO2puls was measured continuously with a finger probe attached to the second finger. The SO2puls- and SO2calc-values differed from the SO2meas-values (p less than 0.05); however, the differences were of no clinical relevance. Performing linear regression analysis, only SO2puls correlated significantly (r = 0.47, p less than 0.001) with SO2meas. Pulse oximetry is able to replace invasive measurements of arterial oxygen saturation in athletes. It is superior to SO2-calculations and permits reliable, valid and non-invasive continuous monitoring of SO2.

Adult↗
PubMed1990

[Diagnosis, prevention and therapy of pulmonary complications in heart surgery interventions].

Pulmonary complications after cardiac surgery may be caused by preexisting disorders of the respiratory system, common risk factors (e.g., smoking), kind and duration of the surgical procedure, and the anesthesia performed. Preoperative lung function measurements do not allow a valid assessment of the frequency and severity of postoperative complications. However, the efficacy of the peroperative management with bronchodilating agents (beta 2-agonists, theophylline, corticosteroids) in patients with airflow limitation should be based on repeated lung-function testing. After coronary artery surgery, the internal mammary artery grafting produces a greater impairment of lung function than does saphenous vein grafting. In patients with mitral valve disease and pulmonary congestion without increased pulmonary vascular resistance lung-function may be improved by mitral valve replacement. Atelectasis and gas-exchange disturbances during anesthesia can be treated by ventilation with PEEP. An adequate and immediate management of postoperative pulmonary complications (atelectasis, respiratory failure, pneumonia) improves the outcome of patients after cardiac surgery. The role of perioperative physiotherapy for the reduction of pulmonary complications after cardiac surgery is not well established.

Coronary Artery Bypass↗
PubMed1990

[Long-term therapy with almitrine dimesilate has no effect on pulmonary hemodynamics at rest and during stress].

A 6-month double-blind study was conducted in 26 patients suffering from a severe obstructive disturbance of ventilation and respiratory insufficiency to find out the behaviour of blood gases and pulmonary haemodynamics under Almitrin treatment compared with placebo. The acute administration of 75 mg Almitrin resulted in a significant increase of PaO2 by 11.7 mmHg, as well as of PAPR by 4.4 mmHg. Statistical significance was seen only for the systolic pressure of the a. pulmonalis. After subsequent 6-month treatment with 3 x 25 mg Almitrin, a significantly higher PaO2 is seen at T6 than in the control group. Another additional administration of 75 mg Almitrin results in a further increase of PaO2 by 7.7 mmHg. At T6 the behaviour of pulmonary haemodynamics is identical in both groups A and P.

Almitrine↗
PubMed1990

[Transcutaneous blood gas measurements in ergometry].

Blood gases were determined simultaneously both transcutaneously and arterially in 23 healthy male subjects during spiroergometric, exhaustion-limited stress. The individual correlation coefficient between arterially and transcutaneously measured pO2/pCO2 was 0.66 and 0.80, respectively. The median correlation coefficient between the individual correlation coefficients of the pO2 and pCO2 measurements was 0.85 (p less than 0.01). Hence, the validity of transcutaneous blood gas measurement under stress is significantly dependent on individual factors that influence both the pO2 and pCO2 measurements to an equal degree.

Blood Gas Monitoring, Transcutaneous↗
PubMed1990

[Prevalence of polyneuropathies in patients with chronic obstructive lung disease].

A multicentric study of 151 COLD patients confirmed the increased prevalence of peripheral polyneuropathies (PNP) in hypoxaemic patients with chronic obstructive lung disease (COLD). 43 (28%) of these 151 COLD patients showed a clinically manifest PNP, whereas in a comparative group of 32 asthmatics there were only 2 clinical PNP cases. Patients with known risk factors for PNP were not included in the study. The polyneuropathy observed in such patients is usually mild, mainly sensorial, distal and leg-accentuated. Of 52 COLD patients with a PaO2 up to 55 Torr, polyneuropathy was seen in 21 (40%), and of 59 COLD patients with a PaO2 above 60 Torr, 10 (17%) had polyneuropathy. In multifactorial genesis (as would be expected), the degree of severity of hypoxaemia (calculated as reduction of the actual PaO2 value below the age-adjusted nominal value), as well as the age of the patient, are statistically significant predictors of clinically manifest PNP.

Aged↗
PubMed1990

[Pneumonia in AIDS: pathogen spectrum and diagnostic value of various fiberoptic bronchoscopy methods for the detection of pathogens].

39 fibre-bronchoscopic examinations were performed prospectively in 29 AIDS-patients with pneumonia. Specimens were obtained from the central bronchial system with a protected brush and by suction, from the infiltrated peripheral area by catheter suction, protected brush, bronchoalveolar lavage (BAL) and transbronchial biopsy in randomized order. In patients with non-bacterial pneumonia, pneumocystis carinii (n = 20) was the most frequent pathogen. In this group BAL had a significantly higher rate of pathogen detection than other techniques. In patients with bacterial pneumonia (n = 10) the pathogens were found in all cases by suction from the central bronchial system. Fibre-bronchoscopy in patients with AIDS and pneumonia should include specimens from the central bronchial system and a bronchoalveolar lavage.

Acquired Immunodeficiency Syndrome↗
PubMed1990

[Anxiety and illness behavior in bronchial asthma].

In 82 patients attending a one-week asthma self-management education program, asthma symptom anxiety, personality trait anxiety, and attack-related coping styles were correlated with attack frequency, medication regimen and pulmonary function parameters. In 21 patients, asthma symptoms anxiety was shown to influence illness behaviour at follow-up one year later: in patients with severe asthma, greater symptom anxiety was associated with more suitable illness behaviour. Moreover, suitable illness behaviour appears to be related to cognitive coping styles that take into account the asthmatic's feeling of dependency in attacks without denying them.

Adaptation, Psychological↗
PubMed1990

[Serologic studies in the diagnosis of pneumonia].

The importance of serological determination procedures for the diagnosis of pathogens was investigated in 207 episodes of pneumonia. The pathogenic organisms were detected in 138 cases; in 40 cases serological analysis helped to establish the diagnosis, while in 11 cases of pneumonia, the diagnosis was possible only with serology. The organisms most commonly found by serological investigations were Cytomegalovirus (n = 10), Aspergillus fumigatus (n = 7), and the influenza B virus (n = 7). Multiple infections, usually triggered by bacterial pathogens, were found in 48% of the cases of pneumonia with serological evidence of pathogens. In 71 episodes of pneumonia, the patients were immunosuppressed; in 11 cases, the causative organism was detected serologically.

Adult↗
PubMed1990

[Validity of calculating oxygen saturation at rest and during exercise].

Oxygen saturation calculated with the formulae proposed by Heck, Kelman, Lutz, Marsoner, Severing-haus and Siggaard-Andersen, was compared with oxygen saturation measured photometrically. An analysis of 1350 peripheral venous, mixed venous and arterial blood samples obtained during bicycle ergometry revealed that only the calculations using the Kelman, Siggaard-Andersen and Severing-haus formulae had adequate validity and reliability over a wide measuring range. If, however, the oxygen saturation figures are to be used for further calculations, direct measurement should be given preference to avoid errors (for example, in shunt calculation).

Exercise Test↗