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Biomedical subjects

M Arborelius

Publications and source records attributed to M Arborelius.

At least 19 recordsLinked to original sources
PubMed1992

Small airways dysfunction among non-smoking shipyard arc welders.

Increased volume of trapped gas (VTG), indicating small airways dysfunction, was found among 14 never smoking non-atopic welders who had worked for 10-31 (mean 22) years in their occupation. Spirometry and nitrogen wash out data were compared with those from a reference group of 14 never smoking men not exposed to welding. A methacholine provocation test was carried out. The effect was measured by change in forced expiratory volume in one second (FEV1) and VTG. The maximum decrease in FEV1 after inhalation of methacholine was 6% in welders and 2% among referents. Before provocation VTG and VTG total lung capacity (TLC) was higher among welders (127 ml v 98 ml and 1.76% v 1.38%). The increase in VTG and VTG/TLC was higher in welders after inhalation of methacholine at concentrations of 0.001% to 2% and remained increased after inhalation of salbutamol. The differences indicate small airways disease among shipyard welders.

Adult↗
PubMed1991

Markers for development of hypertension in commercial flight aviators.

In order to discover markers for the development of cardiovascular disease and hypertension, we studied systolic and diastolic blood pressure, ECG, and heart rate before, during and after exercise; body mass index (BMI); serum cholesterol; and smoking habits in 183 male aviators (mean age 41 years at commencement, and 55 at follow-up). Those developing cardiovascular disease had an overrepresentation of smokers but the disease could not be related to any other variable. By contrast we found the following independent markers for prediction of future hypertension in normotensive aviators: increased BMI, increased diastolic blood pressure at 50 W, low heart rate at maximal exercise and smoking. Of these markers high diastolic blood pressure and low heart rate during exercise are new. Subjects with initially elevated blood pressure who did not develop hypertension decreased their diastolic blood pressure after exercise in contrast to those developing hypertension.

Aerospace Medicine↗
PubMed1990

Pulmonary function in middle-aged women with heterozygous deficiency of the serine protease inhibitor alpha 1-antichymotrypsin.

Heterozygous alpha 1-antichymotrypsin (ACT) deficiency is inherited in an autosomal dominant mode independently of alpha 1-antitrypsin with a gene frequency (q) of 0.003. In a previous study, a high prevalence of enlarged residual volumes in subjects with the trait were noted. Neutrophil cathepsin G, the target proteinase of ACT, enhances the elastolytic action of elastase. Thus, hypothetically, subjects with the trait may have increased risk for developing pulmonary emphysema. To test whether heterozygous ACT deficiency predisposes to lung disease, plasma ACT concentrations were determined in a cohort of 1,872 middle-aged women. Women with subnormal levels were studied with respect to heredity, airway symptoms, and lung function. Twelve women (0.64% of the cohort) were classified as heterozygotes after family studies and were compared with control subjects, matched for age, weight, sex, and smoking status. There were no significant differences in airway symptoms between heterozygotes and control subjects. However, the prevalence of ex-smokers was significantly higher among heterozygotes than among the screened population as a whole (prevalence ratio, 2.18; 95% confidence interval, 1.004-4.72). There were no differences between the heterozygotes and the control subjects in the basal spirometry. However, after bronchodilation, five of the 12 heterozygotes manifested residual volumes greater than 2.5 standard deviations above normal mean compared with one of 24 control subjects (p = 0.012). The present investigation thus confirms our previous findings of an increased prevalence of enlarged residual volumes in heterozygous ACT deficiency.(ABSTRACT TRUNCATED AT 250 WORDS)

Cohort Studies↗
PubMed1990

Pulmonary blood flow distribution in erect man in air and during breathhold diving.

We used intravenously administered 99mTc-labelled macroaggregates and a gamma camera attached to a computer for measuring distribution of pulmonary blood flow per unit lung volume in eight healthy subjects sitting erect in air and also during breathhold diving to 1 or 10 m of depth. We measured distribution of perfusion in the supine position and substituted regional lung volume with regional perfusion in the supine for calculating regional perfusion per lung volume erect in air and during diving. The perfusion per unit lung increased rectilinearly down the lung in subjects below 30 years of age but decreased in the lowermost regions in older subjects. This decrease showed a strong correlation to closing capacity. An age-related decrease in transpulmonary pressure may influence both basal perfusion and closing capacity. During submersion, perfusion became equal in all regions with the exception of the lung apex which became hyperperfused. Close to the diaphragm, small inconsistent changes were noted. Redistribution was the same at surface (1 m of depth) with the lung volume being close to total lung capacity and at 10 m of depth when lung volume was compressed to functional residual capacity. During breathhold diving, high intrapulmonary blood volume and pressure became more important for blood flow distribution than gravity or lung volume, while differences in regional hypoxic vasoconstriction and in transpulmonary pressure seem to explain interindividual variation.

Adult↗
PubMed1989

Comparison of 133Xe clearance and laser Doppler flowmetry in assessment of blood flow changes in human masseter muscle induced by isometric contraction.

Changes induced by 30 s of isometric contraction at 10% and 50% of the maximum voluntary contraction were assessed in 10 healthy subjects; there was a median increase of 1.8 and 0.3 times in 133Xe clearance and 5.3 and 2.7 times in laser Doppler flowmetry. In the first minute after 10% maximum voluntary contraction, 133Xe clearance increased 12.1 times in relation to the initial resting level, and flowmetry values decreased to become 3.5 times higher than the basal flow; corresponding values after 50% maximum voluntary contraction were 24.3 times and 3.7 times. From the second minute after contraction, there was a rapid decrease in 133Xe clearance and a slow decrease in flowmetry values. Five minutes after biting at 10% maximum voluntary contraction, both methods showed a total net increase of about 15 times; after biting at 50% maximum voluntary contraction the corresponding values were 38 and 23 times. Thus laser Doppler flowmetry can be used to assess changes in blood flow in the masseter; it registers a greater increase in flow during isometric contraction than does 133Xe clearance. The significant difference between methods immediately after either chosen level of contraction disappears when the total net post-contraction hyperaemia is assessed over a period of 2 and 5 min, respectively.

Adult↗
PubMed1989

Features of carotid artery flow velocity in healthy subjects and consequences for evaluating stenosis in the internal carotid artery.

C-W-Doppler analysis of flow velocity in the carotid arteries was performed in 98 healthy volunteers, age 16-74 years, 49 of each sex, and in 23 subjects with carotid disease. Maximum frequency shift (MFS) and total band-width in the healthy proximal internal carotid artery were negatively correlated to age in both sexes (p less than 0.001). MFS was lower in the normal proximal internal carotid artery than in the common carotid artery in both sexes. Minimum frequency shifts were more often, and more negative in the proximal than in the distal part of the internal carotid artery (p less than 0.001 in men and less than 0.01 in women) and still more so in the proximal part of the pathological internal carotids as compared with the normal ones (p less than 0.001). The computer-fitted regression between MFS and the degree of angiographic stenosis in the subjects with carotid artery disease was nearly identical with the mathematically calculated relationship for an ellipsoid stenosis. There is reason to believe that the degree of area stenosis calculated from frequency shift and predicted normal values gives a more true interpretation of functional stenosis than angiography, while the latter might be superior for evaluating vascular patho-anatomy, giving information also about intrathoracic and intracranial vessels, which also is important for evaluating patients with TIA and related symptoms.

Adolescent↗
PubMed1989

Nitrogen dead space in heavy smokers aged 44-58 years.

Functional and alveolar dead spaces for nitrogen (VDF and VDalv) were calculated in a population of 20 male and 20 female heavy smokers and compared to data from static and forced spirometry (functional residual capacity [FRC], residual volume [RV], lung clearance index [LCI] and volume of trapped gas [VTG]) obtained with the same multiple-breath nitrogen wash-out as the dead spaces, and to variables considered sensitive to small airways disease measured with a single-breath nitrogen elimination (closing volume in per cent of vital capacity [CV%], closing capacity in per cent of total lung capacity [CC%] and slope index [SI]). Both nitrogen dead spaces increased with tidal volume in smokers as well as in healthy non-smokers. The majority of smokers were outside the predicted mean +2 SD for VTG (75%), CC and VDalv (70%) and SI (65%). The following variables were less sensitive for disclosing abnormality: CV (55%), RV (53%), LCI (38%) and forced expired volume in the first second (FEV1, 33%). If high sensitivity is considered preferable in epidemiological studies, the nitrogen dead spaces are equally as sensitive as the better of earlier described tests, and significantly superior to LCI and FEV1. Being tests that measure alveolar distribution of inhaled gas, they are probably sensitive to small airways disease.

Adult↗
PubMed1988

Prevention of exercise-induced asthma by drugs inhaled from metered aerosols.

The capacity of salbutamol 0.3 mg (SAL), disodium cromoglycate 3 mg (DSCG), a combination (SAL + DSCG), and ipratropium bromide 80 ug (IB), all given as metered aerosols to prevent exercise-induced (EIA), was compared with that of a placebo, a peroral lactose pill. Seven children participated, having reproducible EIA provoked by running on a treadmill at a heart rate of 170 sustained for 6 min. FEV1 and volume of trapped gas (VTG), defined as the air volume released during rebreathing oxygen with maximum breaths at the end of a multiple breath nitrogen wash out, were used as tests of spasm in large and small airways. SAL and SAL + DSCG offered complete protection in large and small airways. DSCG and IB prevented EIA in large airways (FEV1) to 95%, but only to about 50% in small airways (VTG). SAL or SAL + DSCG gave significantly better protection (FEV1 and VTG) than DSCG and IB (P less than 0.01). Differences between DSCG and IB were not statistically significant. DSCG or propellant caused significant irritation and spasm in small airways (VTG) before exercise. Most subjects seemed to obtain satisfactory protection against EIA by beta 2-agonists.

Administration, Inhalation↗
PubMed1988

Multiple breath nitrogen dead space.

Ventilatory efficiency for eliminating CO2 is expressed by the physiological dead space, VD phys = (1-PE CO2/Pa CO2) x VT, where PE is the mixed exhaled and Pa the arterial CO2-tension and VT the tidal volume. We used data from the multiple breath N2-wash-out with oxygen for calculating a functional dead space for nitrogen. VDF N2 = (1-FEN2/FidN2) x VT.FEN2 is the mixed exhaled N2-fraction and FidN2 the calculated mean alveolar N2-fraction during a wash-out with the same number of breaths to reach 2% N2 in end tidal air, but having completely even distribution. FidN2 is shown to be 0.20 +/- 0.01 for wash-outs using 20-150 breaths. The method was applied to wash-outs from 21 healthy volunteers, 18 patients with chronic obstructive lung disease and two subjects with acute bronchospasm. VDF was well related to VD phys CO2 (r = 0.78) but higher than the latter. In subjects with lung disease VDF was inversely related to the degree of obstruction expressed by forced expiratory volume in one second per cent of vital capacity (r = 0.85). The subjects with bronchospasm had very high VD/VTF in relation to their FEV%. If airway dead space predicted from height and sex is subtracted from VDF, the resulting alveolar dead space will be a good expression for uneven gas distribution in the lungs. We also deduced a direct mathematical relation between lung clearance index and VD/VTF. The documented good reproducibility of LCI is thus also valid for VD/VTF, while the latter better expresses ventilatory efficiency.

Breath Tests↗
PubMed1988

Change in plasma amino acid concentrations during breath-hold diving at high altitude.

We studied the plasma concentration of various amino acids in 6 Italian sport divers in Italy and at approximately 4,500 m altitude in Peru; 6 Peruvian inhabitants were examined for comparison. We attempted to create a situation of pronounced hypoxia in muscles by breath-hold diving at altitude. The diving reflex diverts blood away from muscles while diving increases central oxygen tension and prevents loss of consciousness. Differences in certain amino acids, probably related to diet, were noted between Italy and Peru. Increases in concentration of plasma alanine and some branched-chain amino acids occurred after breath-hold diving. These changes were similar to those seen after prolonged hard exercise, even though physical work was low. Hypoxia in muscles, common during hard work and during breath-hold diving at altitude, might thus be the stimulus for amino acid release from working muscles.

Adult↗
PubMed1986

Changes of volume of trapped gas after bronchodilation in subjects with suspected subclinical emphysema.

We studied the volume of trapped gas (VTG), using a nitrogen washout method, before and after bronchodilation in four groups with theoretically increasing risk of developing pulmonary emphysema: (1) nonsmoking healthy controls (PiMn), (2) nonsmoking subjects with an intermediate alpha 1-antitrypsin deficiency (PiMZn), (3) smoking subjects with normal concentration of alpha 1-antitrypsin, and (4) smoking PiMZ subjects. VTG was the only lung function variable that showed a significant difference between PiMZn and PiMn subjects but only after bronchodilation. Some conventional lung function tests also distinguished smokers from nonsmokers of both genotypes but VTG was the most sensitive test. VTG decreased after salbutamol inhalation in the control group but showed a consecutively larger increase with more risk factors of developing emphysema. An increase in VTG after bronchodilation may be a sign of alveolar abnormality preceding development of clinical lung emphysema.

Albuterol↗
PubMed1979

Preoperative normovolaemic haemodilution with dextran 70 as a thromboembolic prophylaxis in total in hip replacement.

The effect of preoperative normovolaemic haemodilution with dextran 70 in 57 patients undergoing total hip replacement for osteoarthritis, was evaluated with respect to the production of thrombosis and pulmonary embolism. The patients were randomly allocated to one group undergoing preoperative haemodilution and one control group receiving 500 ml dextran 70 during operation and again on the second postoperative day. Before operation blood was replaced by dextran 70 to lower the hematocrit to between 25 and 30. The blood drained from the patients was used to replace blood lost at operation. Between 10 and 14 days after operation the patients were examined by perfusion lung scan, chest radiography and bilateral phlebography. Twelve patients also had 133Xe ventilation scans. The incidence of deep vein thrombosis in the two groups did not differ significantly. Pulmonary embolism was significantly decreased in the preoperative haemodilution group. One patient in the control group had clinical symptoms of, and died from, pulmonary embolism.

Aged↗
PubMed1979

Effects of nitroglycerin and dipyridamole on acute myocardial infarction: a thermographic study in the dog.

The effects on an acute myocardial infarction of equipotent hypotensive doses of nitroglycerin and dipyridamole were studied using the thermographic technique in open-chest dogs. Nitroglycerin did not reduce the cool ischaemic area in any of the nine dogs studied. In six of the dogs, in which the ischaemic region could be properly measured, the cool area slightly grew in size. Dipyridamole reduced the size of the ischaemic area in all the 20 dogs used. In the 19 in which the size could be adequately digitalised, the decrease in infarction size was statistically significant.

Acute Disease↗
PubMed1979

Influence of ventilatory frequencies and ventilator volume/pressure quotients on pulmonary ventilation using a tidal volume ventilator.

The influence of ventilatory frequency and the ventilator's "internal state of gas compression" (Cvent) on mechanics of ventilation, pulmonary ventilation, gas distribution, gas exchange and lung perfusion was studied with free airway and experimental regional airway obstruction in 10 piglets (7-12 kg b. w. ), using a tidal volume ventilator. The VDphy/VTexp ratio was greater at f = 30 than at f = 10.3 cycles/min. This could be related to a significant increase in the VDanat/VTexp ratio at f = 30, while VDc/VTexp and VDlav/VTexp were unchanged at both frequencies. With regional ventilation and perfusion within the obstructed pulmonary field were reduced, compared to the values at f = 10.3 cycles/min. With Cvent 20 ml/kPa, the tidal volumes were insufflated in a shorter time and with a higher initial tracheal peak pressure than with Cvent 80 ml/kPa. Following bronchial obstruction, VA, RQ and Pao2 were greater with Cvent 20 than with Cvent 80 ml/kPa. With Cvent 20, the ventilation of the lung bases was reduced, which was compensated for by a large increase in ventilation within the apical areas of the lungs, while gas distribution within the unobstructed areas was more evenly distributed with Cvent 80. Ventilation at Cvent 20 showed no essential advantage over Cvent 80. Only in lungs extremely difficult to ventilate and with ventilatory frequencies over 50 cycles/min could possible indications for Cvent 20 be seen.

Animals↗
PubMed1978

The volume of trapped gas: a new and sensitive test for the detection of exercise-induced bronchospasm in children.

The volume of trapped gas (VTG) was measured at the end of a nitrogen multiple breath wash out procedure in 16 asthmatic and 10 healthy children before and after exercise. When compared to conventional spirometric variables VTG was the most sensitive test for detection of exercise-induced asthma (EIA). The VTG was significantly higher before exercise in the asthmatic children and increased significantly after exercise, while it did not change in the healthy controls. The significance of changes caused by EIA increased if VTG/TLC % or VTG/VC % wer used. Salbutamol inhalation normalized the VTG in all the asthmatic children.

Adolescent↗
PubMed1978

Changes in volume of trapped gas in the lungs during provoked asthma followed by beta-2 receptor stimulation.

The volume of trapped gas (VTG) that could be mobilized by maximal breaths at the end of a nitrogen washout to 2% N2 was measured in 11 subjects with a history of asthma before and after provocation with specific allergens. The change after salbutamol was also measured. VTG was found to be more specific and sensitive for demonstrating early bronchospasm than changes in FEV1, VC or nitrogen washout. Salbutamol relieved all symptoms of bronchospasm.

Adult↗
PubMed1978

Duodenal motility pattern in duodenal ulcer disease.

The motility in the first part of the duodenum has been studied by a method combining roentgen fluorography and multiple pressure recordings in 7 normal volunteers, in 7 patients having gastric, and in 7 having duodenal, ulcer. A significantly lower number of retrograde motor sequences was found in cases with duodenal ulcer than in normals, while patients with gastric ulcers showed no such difference. This abnormality in subjects with duodenal ulcer was interpreted as a deficiency in the transport of neutralized duodenal contents from more distal parts of the duodenum up into the bulb. The abnormality can explain the earlier known lower pH in the duodenal bulb in subjects with duodenal ulcer and contribute to the pathogenesis of the disease.

Duodenal Ulcer↗