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Biomedical subjects

H Koskela

Publications and source records attributed to H Koskela.

13 recordsLinked to original sources
PubMed2001

Stratification of welding fumes and grinding particles in a large factory hall equipped with displacement ventilation.

The purpose of the study was to investigate the performance of displacement ventilation in a large factory hall where large components of stainless steel for paper, pulp and chemical industries were manufactured. The performance of displacement ventilation was evaluated in terms of concentration distributions of welding fumes and grinding particles, flow field of the supply air and temperature distributions. Large differences in vertical stratification patterns between hexavalent chromium (Cr(VI)) and other particulate contaminants were observed. The concentration of Cr(VI) was notably lower in the zone of occupancy than in the upper part of the factory hall, whereas the concentrations of total airborne particles and trivalent chromium (Cr(III)) were higher in the occupied zone than in the upper zone. The stratification of Cr(VI) had the same tendency as the air temperature stratification caused by the displacement flow field.

Air Pollution, Indoor↗
PubMed2001

Laboratory protocol for exercise asthma to evaluate salbutamol given by two devices.

PURPOSE: As new delivery devices and formulations are being introduced for drugs given by inhalation, there is a need to evaluate their equivalence with old preparations. One way to do this is to investigate their equivalence in protecting from exercise-induced asthma (EIA). METHODS: We used a protocol for EIA to compare the protective effect of salbutamol delivered by the pressurised metered dose inhaler (pMDI) and the new Diskus dry powder device. Twenty-seven asthmatic subjects with moderately severe EIA completed an exercise test on four separate days at two study centers. Exercise was performed by cycling for 8 min while inhaling dry air (0% RH, 20-24 degrees C). The target workload in W was predicted as (53.76 x predicted FEV1) - 11.07 and 95% of this target was achieved at 4 min of exercise. This target was chosen in order to achieve ventilation between 50 and 60% of predicted maximum in the last 4 min. RESULTS: There was no significant difference in the workload, ventilation, or heart rate achieved on the study days. The severity of EIA was measured as the % fall in FEV1. EIA severity was similar on the placebo and control day and the coefficient of variation was 19.4%. The mean +/- SD % fall on the control, placebo, salbutamol by Diskus, and pMDI were 42.0% +/- 15, 39.4% +/-17.6, 13.4% +/- 13.2, and 8.5% +/- 13.8, respectively. Salbutamol significantly inhibited the % fall in FEV1 after exercise, and there was no difference between the preparations. CONCLUSION: The protocol described here is suitable for evaluating equivalence of salbutamol preparations in protecting against EIA and could be used to evaluate the protective effect of other medications.

Administration, Inhalation↗
PubMed2001

Predictive markers of asthma exacerbation during stepwise dose reduction of inhaled corticosteroids.

To determine predictors for failed reduction of inhaled corticosteroids (ICS), in 50 subjects with well-controlled asthma (age 43.7 [18-69]; 22 males) taking a median dose of 1,000 microg ICS/d (100-3,600 microg/d), ICS were halved every 8 wk. Airway hyperresponsiveness (AHR) to a bronchial provocation test (BPT) with histamine was measured at baseline. AHR to BPT with mannitol, spirometry, exhaled nitric oxide (eNO), and, in 31 subjects, sputum inflammatory cells were measured at baseline and at monthly intervals. Thirty-nine subjects suffered an asthma exacerbation. Seven subjects were successfully weaned off ICS. Using a Kaplan- Meier survival analysis, the significant predictors of a failure of ICS reduction were being hyperresponsive to both histamine and mannitol at baseline (p = 0.039), and being hyperresponsive to mannitol during the dose-reduction phase of the study (p = 0.02). Subjects older than 40 yr of age tended to be at greater risk of ICS reduction failure (p = 0.059). Response to mannitol and percentage sputum eosinophils were significantly greater before a failed ICS reduction than before the last successful ICS reduction, whereas there were no significant differences in symptoms, spirometry, or eNO. These findings suggest that documentation of patient's AHR or sputum eosinophils may be useful in guiding the reduction of ICS doses.

Adolescent↗
PubMed2001

Markers of airway inflammation and airway hyperresponsiveness in patients with well-controlled asthma.

In steroid-naive asthmatics, airway hyperresponsiveness correlates with noninvasive markers of airway inflammation. Whether this is also true in steroid-treated asthmatics, is unknown. In 31 stable asthmatics (mean age 45.4 yrs, range 22-69; 17 females) taking a median dose of 1,000 microg inhaled corticosteroids (ICS) per day (range 100-3,600 microg x day(-1)), airway responsiveness to the "direct" agent histamine and to the "indirect" agent mannitol, lung function (forced expiratory volume in one second (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF)), exhaled nitric oxide (eNO), and number of inflammatory cells in induced sputum as a percentage of total cell count were measured. Of the 31 subjects, 16 were hyperresponsive to mannitol and 11 to histamine. The dose-response ratio (DRR: % fall in FEV1/cumulative dose) to both challenge tests was correlated (r=0.59, p=0.0004). However, DRR for histamine and DRR for mannitol were not related to basic lung function, eNO, per cent sputum eosinophils and ICS dose. In addition, NO was not related to basic lung function and per cent sputum eosinophils. In clinically well-controlled asthmatics taking inhaled corticosteroids, there is no relationship between markers of airway inflammation (such as exhaled nitric oxide and sputum eosinophils) and airway responsiveness to either direct (histamine) or indirect (mannitol) challenge. Airway hyperresponsiveness in clinically well-controlled asthmatics appears to be independent of eosinophilic airway inflammation.

Adult↗
PubMed2000

Nasal hyperosmolar challenge with a dry powder of mannitol in patients with allergic rhinitis. Evidence for epithelial cell involvement.

BACKGROUND: The responses to airway hyperosmolar challenges probably involve various inflammatory mediators. However, it is not fully understood which cell type/types are the source of these mediators. Potential cell types include mast cell, epithelial cell and the sensory c-fibre nerve cell. OBJECTIVE: To clarify which cell types are involved with the mediator response to hyperosmolarity in the human airway. METHODS: Ten healthy subjects, 11 patients with nonactive allergic rhinitis, and nine with active allergic rhinitis were challenged intranasally with mannitol powder, and with sham provocation, on separate days. Symptoms were assessed by visual analogue scales and nasal patency by measuring the nasal peak inspiratory flow (nPIF). Nasal lavage fluid levels of alpha(2)-macroglobulin (an index of plasma extravasation), substance P (an index of sensory nerve cell activation), tryptase (an index of mast cell activation) and 15-hydroxyeicosatetraenoic acid (15-HETE, an index of epithelial cell activation) were analysed. RESULTS: Immediate, although transient burning was the most prominent symptom in all groups whereas only the patients with active rhinitis experienced a fall in nPIF. Mannitol significantly increased the nasal lavage fluid 15-HETE levels in the allergic patients (P < 0.01 vs the sham challenge), but not in the healthy subjects. The increase in 15-HETE correlated with nasal symptoms for itching (r(s) = 0.65, P = 0.019) and burning (r(s) = 0.72, P = 0.009). Detectable levels of tryptase was found only in five allergic subjects. Lavage levels of substance P and alpha(2)-macroglobulin did not not change. CONCLUSION: Epithelial cell seems to be involved with the mediator response to airway hyperosmolar challenge. The roles of sensory c-fibre nerve cell and mast cell remained less clear.

Adult↗
PubMed2000

Nedocromil sodium inhibits responsiveness to inhaled mannitol in asthmatic subjects.

Nedocromil sodium inhibits the response to exercise-induced asthma (EIA). Mannitol given as a powder by inhalation is an osmotic stimulus that identifies EIA. We studied the acute effect of nedocromil on airway responsiveness to mannitol in 24 asthmatic subjects. After a control day, nedocromil (8 mg) or its placebo was administered randomized, double blind, 10 min before a challenge with progressively increasing doses of mannitol. Nedocromil inhibited the response to mannitol and there was a significant increase in the dose of mannitol required to cause a 15% reduction in FEV(1) (PD(15)) after nedocromil 409 (316,503) mg compared with placebo 156 (106,229) mg (p < 0.001). In the presence of nedocromil 12 subjects no longer recorded a 15% decrease in FEV(1) in response to mannitol. The remaining 12 required a significantly greater dose of mannitol to achieve a 15% decrease in FEV(1) after nedocromil. Following nedocromil, a plateau in responsiveness to mannitol was observed in 14 subjects. Nedocromil significantly inhibits the responsiveness to inhaled mannitol in asthmatic subjects.

Administration, Inhalation↗
PubMed1999

Determinants of bronchial responsiveness at school age in prematurely born children.

The bronchial challenge test using isocapnic hyperventilation of cold air (IHCA) was used to evaluate bronchial responsiveness in 63 offspring of multiple pregnancies when they were 8-15 years old. At birth, 27 (43%) children had had intrauterine growth retardation (IUGR, birth weight <-2 SD, or birth weight difference between twin pairs >1.3 SD). The median birth weight was 2,050 g (range, 800-3, 150), and the median gestational age was 35 weeks (range, 28-38). None of the children had asthma or suffered from asthma-like symptoms. In the interpretation of the IHCA test, a fall of 9% or more in the forced expiratory volume in 1 sec (FEV(1)) was considered as abnormal, and these children were classified as "cold air responders." The number of responders was 16 (25%); their baseline FEV(1)/forced vital capacity ratio (FEV(1)/FVC) and forced expiratory flow between 25-75% FVC (FEF(25-75)), but not FEV(1) were significantly lower than the corresponding values in nonresponders. No differences were found in perinatal or neonatal factors between responders or nonresponders. Eight (30%) of the 27 IUGR and 8 (22%) of the 36 appropriate for gestational age (AGA) children were IHCA responders. In particular, IUGR was not correlated with maximal FEV(1) falls following the IHCA test. Respiratory infections after the neonatal period were equally common in IUGR and AGA children; but infections were associated with subsequent IHCA responsiveness. Adenoidectomy, tonsillectomy, and/or myringotomy had been performed significantly more often in the responders than in the nonresponders. At least one of the above invasive procedures had been performed in 20 (32%) of the children; this group was termed the "ENT (ear, nose, throat) surgery group." Fifty-six percent of the responders, but only 26% of the nonresponders, belonged to the ENT surgery group (P = 0.02). We conclude that intrauterine growth retardation or prematurity is not associated with abnormal cold air responsiveness in the IHCA test.

Adolescent↗
PubMed1998

Responsiveness to mannitol in asthmatic subjects with exercise- and hyperventilation-induced asthma.

We investigated airway responsiveness to mannitol, a new hyperosmolar challenge, in persons hyperresponsive to airway drying. We studied 36 asthmatic subjects, 18 to 40 yr of age, responsive to exercise (n = 23) and eucapnic hyperventilation (n = 28) defined by a 10% fall in FEV1. Fifteen subjects performed both challenges. All subjects performed a challenge with dry powder mannitol, encapsulated and delivered via a Dinkihaler until a 15% decrease in FEV1 was documented or a cumulative dose of 635 mg was delivered. All subjects responsive to eucapnic hyperventilation and all but one subject responsive to exercise were responsive to mannitol. Sixty-nine percent of subjects had a positive response to mannitol after less than 155 mg (6 capsules) and 94% less than 320 mg (10 capsules). The provoking dose of mannitol required to cause a 15% fall in FEV1 (PD15) was related to the severity of the response to exercise (Pearson's correlation coefficient [rp] = 0.68, p < 0.01) and eucapnic hyperventilation (rp = 0.68, p < 0.01) in subjects who were not taking inhaled corticosteroids. The mean (+/- SD) maximum percent fall in FEV1 after mannitol was 24.4 +/- 6.2% and recovery to bronchodilator occurred within 10 min in most subjects. The mannitol test is simple, inexpensive, faster to perform than hyperpnea with dry air and could become an office-based test. Further studies are now required to determine the sensitivity of mannitol to identify exercise-induced asthma in a random population.

Adolescent↗
PubMed1998

Effect of cold air on exercise capacity in COPD: increase or decrease?

STUDY OBJECTIVE: To clarify the effect of cold air on exercise capacity in COPD. DESIGN: Cycle ergometer tests under different environmental conditions. SETTING: Pulmonary function laboratory and an environmental chamber at a university hospital. PARTICIPANTS: Eighteen patients with stable COPD; 14 completed the study. INTERVENTIONS: A preliminary cycle ergometer test followed by two incremental, symptom-limited cycle ergometer tests, one at 24 degrees C and the other at -20 degrees C. MEASUREMENTS: On the first study day: arterial blood gas analysis, 12 to 15 s maximal voluntary ventilation, maximal expiratory flow-volume curves before and 1 h after inhalation of 80 microg of ipratropium bromide, and diffusion capacity of the lung. During the exercise challenges: spirometric indices, minute ventilation (VE), oxygen consumption (VO2), carbon dioxide production (VCO2), facial skin temperature, and heart rate. The feeling of dyspnea was assessed with a visual analogue scale. RESULTS: The maximal work load was 87.5+/-7.3 W at -20 degrees C compared with 96.4+/-6.9 W at 24 degrees C (p<0.05). Accordingly, the exercise duration was shorter in the cold. Exercise dyspnea was more severe in the cold at equal work loads. The shortening of exercise duration induced by cold air correlated with the enhancement of exercise dyspnea. Furthermore, cold air cooled the facial skin and induced immediate bronchoconstriction. VE, VO2, VCO2, and heart rate did not differ between the warm and cold challenges. CONCLUSIONS: Cold air decreases exercise capacity in COPD, probably by increasing exercise dyspnea.

Adult↗
PubMed1995

Facial cooling, but not nasal breathing of cold air, induces bronchoconstriction: a study in asthmatic and healthy subjects.

Reflex-mediated bronchoconstriction in cold climates may be more important than it has previously been thought. This issue has seldom been studied using physiological methods. We wanted to investigate, using physiological methods, what triggers the bronchoconstriction occurring at cold ambient temperature during resting nasal ventilation: cooling of the skin of the face or cooling of the nasal cavity. Three experiments were carried out in 15 stable asthmatics and 10 healthy volunteers: 1) a whole-body exposure to subfreezing temperature in an environmental chamber, during which the subjects breathed cold air through the nose; 2) a similar exposure to subfreezing temperature except that the subjects now breathed warm air through the mouth from outside the chamber; and 3) nasal breathing of subfreezing air from a heat exchanger whilst the subjects sat at room temperature. Spirometric values and facial skin temperature were measured both during and after the exposures. Maximal decrements (means +/- standard errors) of forced expiratory volume in one second (FEV1) in experiments 1, 2 and 3 were: 5.8 +/- 0.8, 5.1 +/- 0.7 and 2.1 +/- 0.5%, respectively (p < 0.001). Only the two experiments in the environmental chamber induced significant bronchoconstriction. All responses were of similar magnitude in the asthmatic and the healthy subjects. The cooling of the skin of the face seems to be the trigger for the bronchoconstriction during resting nasal ventilation at cold ambient temperature both in asthmatic and nonasthmatic subjects.

Adult↗
PubMed1994

Effect of whole-body exposure to cold and wind on lung function in asthmatic patients.

To assess the effect of subfreezing temperature and wind on lung function in asthmatic patients, an exposure to subfreezing temperature at rest, a moderate exercise challenge at subfreezing temperature, and a similar exercise challenge at room temperature were performed in 19 stable asthmatic subjects in an environmental chamber with an artificial wind. The mean maximal falls in FEV1 were 5.3, 11.7, and 4.8 percent, respectively. The two challenges at subfreezing temperature caused statistically significant changes in FEV1, but the exercise challenge at room temperature had no effect. A large variation in the sensitivity to cold was found. The time courses of the responses varied between the challenges, suggesting at least partially different mechanisms. The results indicate that even moderate exercise can cause severe bronchoconstriction in certain stable asthmatic subjects at climatic conditions similar to the Scandinavian winter. The importance of reflex mechanisms causing bronchoconstriction in physiologic conditions is discussed.

Adult↗
PubMedDate not supplied

Prevalence and risk factors of genital human papillomavirus (HPV) infections in healthy males: a study on Finnish conscripts.

BACKGROUND AND OBJECTIVES: Prevalence of genital human papillomavirus (HPV) infection in the general population is not known. No one test alone can detect all HPV infections. GOAL OF THIS STUDY: To determine the prevalence of and risk factors for genital human papillomavirus (HPV) infections in healthy males. Voluntary Finnish Army conscripts were examined using peniscopy, cytology (PAP smear) and polymerase chain reaction (PCR) in brush cytology samples. STUDY DESIGN: A total of 1,471 (99.6%) males completed the questionnaire soliciting their sexual habits, and 432 of them enrolled in the clinical study. RESULTS: The study group differed from the nonattenders in that they reported more often genitourinary symptoms (P < 0.001), had more casual sexual partners (P = 0.002), and previous STDs (P < 0.001). Classical genital warts were present in 24/432 (5.6%) and papular lesions in 8/432 (1.9%) males. Acetowhite lesions were disclosed in 151/432 (35.0%) cases, of which 61 (14.1%) had peniscopically typical flat HPV lesions. Koilocytes were found in 13/201 (6.5%) PAP smears. HPV DNA was disclosed by PCR in 16.5% (47/285) of the adequate cell smears, and in 7.1% of the males with no peniscopic abnormalities. When considering the men with HPV-positive PCR findings and/or typical peniscopic pattern as HPV-infected (26.2%), many casual partners, previous STDs and no use of condom were significant risk factors for genital HPV infections in the logistic regression analysis. CONCLUSIONS: The reliable assessment of the prevalence of genital HPV infections in healthy males is not only skewed by the selection of the study group by symptoms and promiscuity, but also by the lack of a universally acceptable screening method. The data confirm sexual promiscuity as the most important risk factor for genital HPV infections.

Adult↗