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PubMed1990

Aspergillus endocarditis after open heart surgery: an epidemiological investigation.

The occurrence of aspergillus endocarditis in four patients after open heart surgery, within a period of 10 months, in a centre where no case had been encountered in the previous 7 years, led us to investigate the possible source and factors contributing to this 'outbreak'. The ventilation system, air conditioning plant, air and inanimate sources in the operating theatre were investigated. With the exception of the operating room which was fitted with laminar air flow, it was possible to isolate Aspergillus spp. from all rooms in the operating suite. Air conditioner cooling coils and pigeon droppings on the ledges outside the suite were found to harbour aspergillus spores in large amounts. The ubiquitous presence of Aspergillus spp. in the operating suite indicated that the existing ventilation system was ineffective in eliminating aspergillus spores from the operating environment. The use of a newly introduced broad spectrum antibiotic protocol seemed to be a major contributory factor according to incidental evidence (although no case control studies were done). Improvements in the ventilation system and the restriction of newly introduced antibiotics was recommended. No further case of fungal endocarditis was observed up to the time of reporting (6 months after the last case).

Adult↗
PubMed1999

Synthetic zeolites and other microporous oxide molecular sieves.

Use of synthetic zeolites and other microporous oxides since 1950 has improved insulated windows, automobile air-conditioning, refrigerators, air brakes on trucks, laundry detergents, etc. Their large internal pore volumes, molecular-size pores, regularity of crystal structures, and the diverse framework chemical compositions allow "tailoring" of structure and properties. Thus, highly active and selective catalysts as well as adsorbents and ion exchangers with high capacities and selectivities were developed. In the petroleum refining and petrochemical industries, zeolites have made possible cheaper and lead-free gasoline, higher performance and lower-cost synthetic fibers and plastics, and many improvements in process efficiency and quality and in performance. Zeolites also help protect the environment by improving energy efficiency, reducing automobile exhaust and other emissions, cleaning up hazardous wastes (including the Three Mile Island nuclear power plant and other radioactive wastes), and, as specially tailored desiccants, facilitating the substitution of new refrigerants for the ozone-depleting chlorofluorocarbons banned by the Montreal Protocol.

Journal Article↗
PubMed1992

Indoor Air '90: the 5th in a series of international conferences on the indoor environment.

The 5th International Conference on Indoor Air Quality and Climate: INDOOR AIR '90 continued a series of international scientific conferences begun in 1978 on a complex, interdisciplinary subject increasingly recognized to be of importance to human comfort, health and productivity, and having important implications for building design and furnishing, office equipment, appliances, cleaning, heating, ventilating, humidifying and air-conditioning. INDOOR AIR '90 constituted a week long program of 542 paper and poster presentations and forum discussions, 100 exhibits, and a public forum. This paper summarizes some of the highlights of this conference and links these to some of the studies reported at earlier INDOOR AIR Conference.

Air Pollution, Indoor↗
PubMed1986

Respiratory heat loss in exercise-induced asthma. Measurement and clinical application.

The theoretical considerations of conditioning inspired air and the application of the respiratory heat loss (RHL) formula are discussed. An on-line method for measuring RHL is described together with the apparatus for generating frigid dry and warm humid air. Exercise-induced asthma (EIA) was studied using these methods. Thirteen asthmatic and 6 normal children and adolescents participated in the study. Each subject undertook two submaximal exercise tests consisting of 6 minutes' ergometric cycling against a fixed load. One test was done while breathing cold dry air (mean temperature -22 degrees C and 0% relative humidity) and the other while breathing warm humid air (mean temperature 36 degrees C and 100% relative humidity). All the other exercise parameters (e.g. heart rate, minute ventilation, oxygen uptake) were carefully matched between the two tests. In the cold dry air tests with a mean RHL of 1,43 kcal/min, all asthmatic subjects developed EIA with a mean fall in forced expiratory volume in the 1st second (FEV1) of 48% from baseline. In the warm humid air tests with negligible RHL (0,02 kcal/min) none of the asthmatics developed EIA (mean fall in FEV1 5%). The difference between the two tests was highly significant (P less than 0,001). Neither air condition caused bronchospasm in the normal subjects. A dose-response relationship was obtained between the degree of RHL and corresponding fall in FEV1.

Adolescent↗
PubMed1980

[Microbiological aspects of Legionnaires' disease].

Legionella pneumophila was isolated in 1947 but its etiological role was only recognized after the Philadelphia outbreak in 1976. Since then, infections with Legionella pneumophila in patients with so-called atypical pneumonia have been found in different parts of the world in sporadic cases and outbreaks affecting up to several hundred patients. The etiological agent is a bacterium which can be found in dust, mud and water. Transmission to the human most likely occurs through water-cooled air condition units or showers. Air conditioning in hotels, hospitals and offices may transmit the organism and lead to infection which, moreover, is more frequent during the warm season. The diagnosis is based on clinical data and the demonstration of specific antibodies. Isolation of the agent is technically difficult and up to now only approximately 3% of the cases have been confirmed by isolation of the agent. Evidence of Legionella pneumophila infection in Switzerland was obtained by testing stored blood samples from transplanted patients in 1970. Sporadic cases were observed in the period 1977 to 1980. Acute infection was considered in 141 patients on the basis of serological results. Approximately 3% of all pneumonias in 1979 were caused by Legionella pneumophila. Isolation of the etiological agent has been achieved in 3 patients only.

Antibody Formation↗
PubMed2004

Decreased respiratory symptoms after intervention in artificially ventilated offices in São Paulo, Brazil.

BACKGROUND: The increase in work-related respiratory complaints in artificially ventilated buildings have multiple causes, and intervention studies are a valuable approach to understanding possible mechanisms. STUDY OBJECTIVES: To analyze the effects of an intervention in a ventilation system with > 20 years of continuous use, and with a high rate of building-related respiratory complains. DESIGN: An epidemiologic study was done among individuals working in places with ventilation machinery and ducts with > 20 years of use, before and after intervention. Analysis of symptoms and logistic regression were performed to check the associations between air-conditioning intervention and reported symptoms. RESULTS: The air-conditioning intervention showed a protective effect on building-related worsening of respiratory symptoms (odds ratio, 0.132; 95% confidence interval, 0.030 to 0.575), naso-ocular symptoms (odds ratio, 0.231; 95% confidence interval, 0.058 to 0.915), and persistent cough (odds ratio, 0.071; 95% confidence interval, 0.014 to 0.356). CONCLUSION: Intervention in high-risk occupational locations can be effective in improving perceived indoor air quality.

Air Conditioning↗
PubMed1989

Cytochrome c-551 from the thermophilic bacterium PS3 grown under air-limited conditions.

A small-sized c-type cytochrome, designated cytochrome c-551, was prepared from membrane fraction of the thermophilic bacterium PS3 grown under air-limited conditions by extraction with cholate, precipitation with polyethylene glycol, and successive chromatographies with DEAE-cellulose and Sephacryl S-200 in the presence of a detergent. The purified sample contained approximately 1 mol of heme c per 10,000 g protein; it showed absorption bands at 551, 522 and 416 nm upon reduction, and a Soret peak at 409 nm upon oxidation. This cytochrome showed a single band of 10 kDa on polyacrylamide gel electrophoresis with sodium dodecyl sulfate. The isoelectric point of this cytochrome c-551 was pH 4.0. Cytochrome c-551 was suggested to play an important role in the respiratory chain with a terminal oxidase cytochrome o, which is produced under air-limited conditions, since cytochrome c-551 could mediate electron transfer between cytochrome bc1(b6f) complex and cytochrome o, showing quinol oxidase activity.

Bacterial Proteins↗
PubMed1991

Particle penetration into the automotive interior. I. Influence of vehicle speed and ventilatory mode.

Penetration of particulate aeroallergens into the interiors of two, new, similar Chrysler Corporation passenger vehicles (having no evidence of intrinsic microbial contamination) was studied on a large circular test track during periods of high pollen and spore prevalence. Impactor collections were obtained at front and rear seat points and at the track center during periods with (1) windows and vents closed and air conditioning on, (2) windows closed, vents open, and no air conditioning, and (3) air conditioner off, front windows open, and vents closed. These conditions were examined sequentially during travel at 40, 50, 60, and 80 kph. Particle recoveries within the two, new, similar Chrysler Corporation passenger vehicles did not vary with the speed of travel, either overall or with regard to each of the three ventilatory modalities. In addition, collections at front and rear seat sampling points were comparable. Highest interior aeroallergen levels were recorded with WO, and yet, these levels averaged only half the concurrent outside concentrations at track center. Recoveries within the cars were well below recoveries obtained outside when windows were closed (both VO and AC modes). These findings suggest window ventilation as an overriding factor determining particle ingress into moving vehicles. Efforts to delineate additional determinants of exposure by direct sampling are feasible and would appear essential in formulating realistic strategies of avoidance.

Aerosols↗
PubMed1989

Reaction time and movement time after active and passive smoking.

Reaction time and movement time were studied following active and passive smoking in two groups of 20 women. All subjects were tested under a clean air and smoky air condition and the results showed that, while there was no difference between groups for either measure in the clear air condition, the active smokers had faster reaction time and movement time in the smoky air condition. Smoky air had no significant effect on the responses of the passive smoking group.

Female↗
PubMed1995

An outbreak of occupational dermatosis in an electronics store.

An outbreak of skin disorders was noted by the primary care physician responsible for the health care of 52 employees in an electronics store. The cases occurred after termite treatment of the store, and the breakdown of the air-conditioning system in several areas in the store. Investigations were initiated to allay worker concern that the chemicals used for termite treatment (in particular, arsenic trioxide) were responsible for the outbreak. 9 of the 52 workers were found to have heat rash (miliaria rubra). 21% (7) of workers who worked in non-air-conditioned areas had heat rashes, as compared to 11% (2) of workers who worked in air-conditioned work zones. 2 workers had contact dermatitis due to exposure to greaseless lubricant, and 8 other workers had a non-work-related skin disorder. Indoor wet bulb globe temperature index measurements in the non-air conditioned areas were within threshold limit values, but ventilation in these areas was very poor. 2 environmental samples had non-detectable limits of arsenic.

Air Conditioning↗
PubMed1995

[Heat and moisture exchangers for conditioning of inspired air of intubated patients in intensive care. The humidification properties of passive air exchangers under clinical conditions].

Heat and moisture exchangers (HME) are used as artificial noses for intubated patients to prevent tracheo-bronchial or pulmonary damage resulting from dry and cold inspired gases. HME are mounted directly on the tracheal tube, where they collect a large fraction of the heat and moisture of the expired air, adding this to the subsequent inspired breath. The effective performance depends on the water-retention capacity of the HME: the amount of water added to the inspired gas cannot exceed the stored water uptake of the previous breath. This study evaluates the efficiency of four different HME under laboratory and clinical conditions using a new moisture-measuring device. METHODS. In a first step, the absolute efficiency of four different HME (DAR Hygrobac, Gibeck Humid-Vent 2P, Pall BB 22-15 T, and Pall BB 100) was evaluated using a lung model simulating physiological heat and humidity conditions of the upper airways. The model was ventilated with tidal volumes of 500, 1,000, and 1,500 ml and different flow rates. The water content of the ventilated air was determined between tracheal tube and HME using a new high-resolution humidity meter and compared with the absolute water loss of the exhaled air at the gas outlet of a Siemens Servo C ventilator measured with a dew-point hygrometer. Secondly, the moisturizing efficiency was evaluated under clinical conditions in an intensive care unit with 25 intubated patients. Maintaining the ventilatory conditions for each patient, the HME were randomly changed. The humidity data were determined as described above and compared with the laboratory findings. RESULTS AND DISCUSSION. The water content at the respirator outlet is inversely equivalent to the humidity of the inspired gases and represents the water loss from the respiratory tract if the patient is ventilated with dry gases. Moisture retention and heating capacity decreased with higher volumes and higher flow rates. These data are simple to obtain without affecting the patient and can easily be interpreted. It was demonstrated that, compared to physiological conditions, the DAR Hygrobac and Gibeck Humid Vent 2P-HME coated with hygroscopic salts-were able to maintain sufficient inspiratory humidity and heat. The Pall-HME, solely a condensation humidifier, did not meet the physiological requirements.

Adult↗
PubMed1989

Genetic typing in a cluster of Legionella pneumophila infections.

Legionella pneumophila strains isolated from six patients, three air-conditioning- and cooling tower-derived strains, and three hot water supply-derived strains were analyzed by three genetic typing methods. The results of the whole-cell DNA restriction endonuclease analysis and the restriction patterns based on genes coding for rRNA correlated with each other and demonstrated that the patient isolates were indistinguishable from the air-conditioning- and cooling tower-derived isolates but differed markedly from the hot water supply-derived isolates. The patient and air-conditioning- and cooling tower-derived strains contained plasmids of the same molecular weight; the hot water supply-derived strains were plasmidless. These results indicated that the cooling tower or the air-conditioning system was the environmental source for the examined cluster of Legionnaires disease strains.

Air Conditioning↗
PubMed1995

Seasonal changes in ambulatory blood pressure in employees under different indoor temperatures.

OBJECTIVE: The effect of indoor temperature control on summer and winter ambulatory blood pressure levels at work was studied. METHOD: Ambulatory systolic blood pressure (SBP) and diastolic blood pressure (DBP) were monitored once in summer and once in winter in 101 healthy normotensive subjects aged 28-63 years, engaged in similar physical work, from two plants with and three without air conditioning. Subjects were interviewed about health related habits, and measurements of environmental and occupational conditions were obtained. RESULTS: After controlling for possible confounders, mean SBP and DBP during work were significantly higher in winter than in summer (delta SBP = 3.4 mm Hg, P = 0.035; delta DBP = 3.3 mm Hg, P < 0.003). The seasonal change in SBP and DBP showed an independent association with the presence or absence of air conditioning of the industrial plants (SBP: beta = 0.194, P < 0.0001; DBP: beta = 0.054, P = 0.038). The percentage of subjects with increases of more than 10 mm Hg from summer to winter was higher in plants without than with air conditioning. CONCLUSIONS: (1) In normotensive subjects ambulatory working BP varies by season, with higher values in winter. If validated for hypertensive subjects, it may be necessary to tailor drug treatment to these variations. (2) The findings make it clear that drawing valid conclusions from comparisons of BPs between groups requires controlling for several factors, particularly season of the year. (3) Climatic conditions in the industrial plant influence the magnitude of seasonal variations in BP. Work in plants without air conditioning places a considerable added load on the employee's cardiovascular system.

Adult↗
PubMed1989

[Evaluation of technical indoor air ventilation systems in operating departments from the health viewpoint].

By means of measurement examples it is shown that the examination of the cfu-concentration in the supply-air is not a sufficient criterion for the hygienic-microbiological evaluation of air-conditioning systems in operation wards. Maximum upper values for cfu-concentration were only exceeded a little in some cases. Particle measurements, carried out simultaneously, gave further information on the hygienic status of the air supplied by the air-conditioning system and permitted an evaluation of the ventilation system (for example an air-supply ceiling with a stabilized air ventilation). An efficient air-ventilation system should have the effect that the air quality in the operation area is of nearly the same quality as the supply-air. On the basis of own measurements maximum upper values and recommended values for cfu- and in particular particle-concentrations in the supply-air of air-conditioning systems with three-step filtration were proposed. The set-up and the carrying out of the measurement is described to standardize a "hygienic evaluation" of air-conditioning systems in operation theatres. Help for the interpretation of measurement results is given by means of measurement examples.

Air Microbiology↗
PubMed1980

[Optimum utilization of the ventilation system to reduce airborne bacteria in operating rooms].

In 4 operating theatres with 4 different air-conditioning equipments, the number of bacteria per m3 circulating air in the neighbourhood of the open wound has been investigated. The testing has been performed on comparable aseptic operations. The worst results were obtained in 2 conventional theatres, equipped with a modern-up-to-date air-conditioning. The number of bacteria was ranging between 230 and 270 per m3. A much better results was obtained in a theatre, equipped with a so-called germ-stop-wall, dividing the theatre into 2 sections, separating the surgical team and the open wound completely from the anaesthesist and other staff. With this arrangement, 45 germs per m3 were found. The best result with no bacteria at all is present in a vertical flow-enclosure with an exchange rate of 32 per hour. According to our 10-year experience, for aseptic surgery sterile air techniques should be adopted to improve asepsis and to decrease the risk of postoperative infection.

Air Conditioning↗
PubMed2001

The nasal passage of subjects with asthma has a decreased ability to warm and humidify inspired air.

We previously showed that individuals with seasonal allergic rhinitis (SAR) had a reduced ability to condition air, which was improved by inflammation. We hypothesized that individuals with perennial allergic rhinitis (PAR) would condition air like SAR with inflammation. Because individuals with asthma usually have inflammation in the nose, we hypothesized that they would condition air like individuals with PAR. We performed a prospective, parallel study on 15 normal subjects, 15 subjects with SAR outside their allergy season, 15 subjects with PAR, and 15 subjects with asthma. Cold, dry air (CDA) was delivered to the nose and the temperature and humidity of the air were measured before entering and after exiting the nasal cavity. The total water gradient (TWG) was calculated and represents the nasal conditioning capacity. The TWG in the SAR group was significantly lower than that in normal subjects. There were no significant differences in TWG between the PAR and normal groups. Subjects with asthma had a significantly lower TWG than did normal subjects. There was a significant negative correlation between TWG and Aas score in the group with asthma (r(s) = -0.8, p = 0.0007). Our data show that subjects with asthma have a reduced ability of the nose to condition CDA compared with normal subjects, but which is similar to SAR out of season.

Adolescent↗
PubMed1982

Risk factors for heatstroke. A case-control study.

To identify risk factors associated with heatstroke, a case-control study in St Louis and Kansas City, Mo, was conducted during July and August 1980. Questionnaire data were gathered for 156 persons with heatstroke (severe heat illness with documented hyperthermia) and 462 control subjects matched by age, sex, and neighborhood of residence. A stepwise linear logistic regression procedure was used to identify factors significantly associated with heatstroke. Alcoholism, living on the higher floors of multistory buildings, and using major tranquilizers (phenothiazines, butyrophenones, or thioxanthenes) were factors associated with increased risk. Factors associated with decreased risk were using home air conditioning, spending more time in air-conditioned places, and living in a residence well shaded by trees and shrubs. Being able to care for oneself, characteristically undertaking vigorous physical activity, but reducing such activity during the heat, and taking extra liquid were also associated with decreased risk. Our findings also suggest effective preventive measures. During a heat wave, the greatest attention should be directed toward high-risk groups, and relief efforts should include measures shown to be associated with reduced risk.

Air Conditioning↗