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At least 883 records · Page 49Linked to original sources
PubMed2005

Indoor air quality investigation and health risk assessment at correctional institutions.

A comprehensive indoor air-quality (IAQ) investigation was conducted at a state correctional facility in New Jersey, USA with a lengthy history of IAQ problems. The IAQ investigation comprised preliminary indoor air screening using direct readout instrumentation, indoor air/surface wipe sampling and laboratory analysis, as well as a heating, ventilation, and air-conditioning system evaluation, and a building envelope survey. In addition to air sampling, a human health risk assessment was performed to evaluate the potential for exposure to site-related air contaminants with respect to the inmate and worker populations. The risk assessment results for the prison facility indicated the potential for significant health risks for the inmate population, possibly reflecting the effects of their confinement and extended exposure to indoor air contaminants, as compared to the prison guard and worker population. Based on the results of the risk assessment, several mitigation measures are recommended to minimize prison population health risks and improve indoor air quality at prison facilities.

Air Pollution, Indoor↗
PubMedDate not supplied

Time-resolved confocal analysis of antibody penetration into living, solid tumor spheroids.

The in vivo function of a biologically active molecule is governed in part by the dynamics of its distribution within its target tissue. To enhance our ability to probe living cells, we have endeavored to improve live confocal microscopy methods and to develop analytical methods that simplify the handling of the resulting complex data sets. To do this we attached a recently developed micro-incubation system to the stage of a Leica confocal laser scanning microscope and were able to maintain physiologic culture conditions over several hours. Axial stability was achieved by modifying the room air conditioning. Laser illumination was low enough to retain cell viability through several hours of continuous scanning. With this setup, planar, time-resolved data sets (xyt) were produced by continuously rescanning a single xy plane at the rate of one scan/min. As an alternative, volumetric data sets (xyz) were acquired by stepping the scanned plane through the z axis. In both types of data sets, a semi-quantitative determination of the concentration of a fluorescent reporter molecule (e.g., FITC) over a gray level range of 0.255 was recorded along with the positional information. Thus, concentration (as intensity of fluorescence, or i) gave a fourth variable by either scan method, resulting in high-density xyti or xyzi data sets. The biological model we used to examine these methods was the penetration of a FITC-labeled, anti-carcinoma monoclonal antibody into cultured spheroids of tumor cells bearing the antibody-binding epitope. In one case, the distribution of antibody-FITC conjugate was compared with that of a long wavelength membrane dye, DiIC18(5). Several different software analyses were compared, including examining xyt data sets as "volumes". We observed that by increasing the displayed resolution of one variable, the demonstrable resolution of the other variables was reduced. For example, with high temporal resolution, either quantitative or positional resolution had to be sacrificed. Thus, we needed to perform several different analyses of a single data set to compare all of the variables properly. In these experiments, the dynamic aspects of the changes in antibody-FITC distribution were examined. Along with comparison of antibody-FITC penetration with that of DiI, these data suggest an as yet unexplained biological transport of antibody into a tumor spheroid, which is not consistent with mere passive diffusion through the fluid of extracellular clefts. Using this model system, we have performed and analyzed highly time-resolved confocal microscopy on living specimens maintained under physiologic conditions.

Adenocarcinoma↗
PubMed1993

Hyperoxia decreases cyclooxygenase activity in endothelial cells.

We examined the effect of hyperoxia on arachidonic acid (AA) metabolism in bovine carotid artery endothelial cells (CAEC) and pulmonary artery endothelial cells (PAEC). Confluent monolayers were exposed to hyperoxic gases (95% O2 or 60% O2) from 12-72 h. Control cells were incubated under normoxic condition (air-5% CO2). After exposure of the cells to normoxic or hyperoxic conditions, prostaglandin (PG) synthesis activity was analyzed in cell homogenates using thin layer chromatography; release of 6-keto-PGF1 alpha, a stable metabolite of PGI2, into the culture medium was measured using a radioimmunoassay. The major metabolites formed from exogenously supplied 14C-AA were 6-keto-PGF1 alpha and a small amount of PGE2. Hyperoxia (95% O2) decreased the synthesis of these cyclooxygenase products beginning at 24 h; moderate hyperoxia (60% O2) had no such effect. There was no significant difference between CAEC and PAEC with respect to the depletion effect of hyperoxia. After 72 h of exposure to 95% O2, endothelial injury was observed in CAEC but not in PAEC. We conclude that hyperoxia decreases cyclooxygenase activity in endothelial cells, and that this decrease is dependent on the severity of the hyperoxia. In addition, CAEC are more susceptible to hyperoxia-induced injury than PAEC. The depletion of cyclooxygenase activity and the resultant effect on PGI2 and PGE2 production may be a factor in the development of hyperoxia-induced endothelial injury.

Animals↗
PubMed2001

Heat transfer properties, moisture loss, product yield, and soluble proteins in chicken breast patties during air convection cooking.

Chicken breast patties were processed in an air convection oven at air temperatures of 149 to 218 C, air velocities of 7.1 to 12.7 m3/min, and air relative humidities of 40 to 95%. The air humidity was controlled via introducing steam into the oven. The patties were processed to a final center temperature of 50 to 80 C. Heat flux, heat transfer coefficient, moisture loss in the cooked chicken patties, the product yield, and the changes of soluble proteins in the product were evaluated for the cooking system. During cooking, heat flux varied with the processing time. Heat flux increased with increasing air humidity. The effective heat transfer coefficient was obtained for different cooking conditions. Air humidity in the oven affected the heat transfer coefficient. The moisture loss in the cooked products increased with increasing the final product temperature and the oven air temperature. The soluble proteins in the cooked patties decreased with increasing the final product temperature. Increasing humidity increased heat transfer coefficient and therefore reduced cooking time. Reducing oven temperature, reducing internal temperature, and increasing air humidity increased the product yield. Soluble proteins might be used as an indicator for the degree of cooking. The results from this study are important for evaluating commercial thermal processes and improving product yields.

Animals↗
PubMed2001

Childhood asthma and indoor allergens: the classroom may be a culprit.

Asthma has become the most common chronic illness among children. Indoor environments appear to play a substantial role in the development of asthma. Recent studies indicate strong evidence of a causal relationship between exposure to certain indoor environmental pollutants and development and/or exacerbation of asthma in susceptible individuals. Allergens of concern include those produced by dust mites, cockroaches, cats, dogs, and molds. It is important to better understand this relationship and take preventive and corrective steps to reduce or eliminate these sources in schools, homes, and day care centers. Measures include tracking of asthma and allergic response incidents; monitoring for the presence of allergens and molds; effective cleaning procedures; prompt repair of water leaks and/or moisture problems; control of indoor relative humidity; and proper operation of heating, ventilation, and air conditioning (HVAC) systems.

Age Factors↗
PubMed1980

Air flow patterns in the operating theatre.

Bacteria-carrying particles and exhaled anaesthetic gases are the two contaminants found in the air flow patterns of operating rooms. Their origin, direction and speed were illustrated by a motion picture using Schlieren photography and smoke tracers. Compared with a conventionally well air conditioned operating theatre, it was shown that a downward flow of clean air reduced the number of bacteria-carrying particles at the wound site by sixty times. The Exflow method of achieving this without the restriction of any side panels or floor obstruction was described. The total body exhaust worn by the surgical team was shown to reduce the bacteria count by a further eleven times. Clinical results show that when both these systems are used together, patient infection was reduced from 9 per cent to between 0.3 per cent and 0.5 per cent, even when no pre-operative antibiotics were used. Anaesthetic gas pollution was measured and shown to be generally 1000 p.p.m. at the head of the patient, in induction, operating and recovery rooms, also in dental and labour rooms. A high volume low pressure active scavenging system was described together with its various attachments including one specially for paediatric scavenging. Results showed a reduction of nitrous oxide pollution to between zero and 3 p.p.m. The economy and cost effectiveness of both these pollution control systems was shown to be good due to the removal of health hazards from patients and theatre staff.

Air Microbiology↗
PubMed1987

Medical services: nitrous oxide pollution in operating theatres.

The efficiency of facilities available for anaesthetic gas scavenging in East Anglian hospitals has been assessed using infrared spectrophotometry. Simple scavenging systems proved to be very effective and reduced the ambient nitrous oxide levels by a factor of ten. Sources of pollution outside of the influence of a scavenging system were due to damaged breathing systems, leaking ventilators and the anaesthetic technique. High levels could be further aggravated by poor maintenance of air conditioning equipment.

Air Pollutants, Occupational↗
PubMed1976

Mathematical model of man's tolerance to cold using morphological factors.

A mathematical model has been developed to anticipate the physiological responses and the thermal state of a naked human under exposure to cold, taking into account his morphological characteristics (skinfold, size, weight) and the environmental conditions (air or water temperature and velocity, barometric pressure and hygrometry). The skinfold conditions the body's thermal conductance and the metabolism depends both on rectal (Tre) and mean skin (Tsk) temperatures. After being tested, this model was used to study the evolution of Tre. It shows the influence of the skinfold which accounts for most of the inter-individual differences. It also permits discussion of survival possibilities during immersion and completes data provided by previously established curves.

Body Surface Area↗
PubMed2000

Thiol disulfide exchange modulates the activity of aldose reductase in intact bovine lens as a response to oxidative stress.

The reversibility of S-thiolation of aldose reductase was shown in intact bovine lens subjected to oxidative stress. The glutathione modified aldose reductase generated in the lens as a consequence of hyperbaric oxygen treatment was recovered in its reduced form following culturing in normobaric air conditions. Nucleus and cortex were differently affected by both oxidative treatment and normobaric air recovery. The extent of S-thiolation of aldose reductase appeared to be higher in the nucleus than in the cortex. Moreover, the nucleus, but not the cortex, was unable to completely recover from the protein S-thiolation process. The ratios of GSH/GSSG and NADPH/NADP(+)as well as the Energy Charge values were determined in the cortex and nucleus both after oxidative stress and recovery. The results are consistent with the existence of a quite well-defined boundary between the two lens regions. Moreover, they are supportive of the hypothesis that thiol/disulfide exchange has the potential to be a regulatory mechanism for certain enzymes which can modulate the flux of NADPH inside the cell.

Aldehyde Reductase↗
PubMedDate not supplied

Health effects from indoor air pollution: case studies.

In recent years there has been a growing awareness of the health effects associated with the presence of contaminants in indoor air. Numerous agents can accumulate in public buildings, homes and automobiles as a result of ongoing activities that normally occur in these closed spaces. Ventilation is a major factor in the control of indoor air pollutants since proper movement of air can prevent or minimize the build up of compounds in buildings. The recent emphasis on energy conservation has lead to measures which economize on energy for heating and air conditioning, but which also trap pollutants within a building. Three cases of indoor air pollution were investigated. A typical investigation of indoor air pollutant problems includes the following: interviews with building occupants; history of the building with regard to maintenance, pesticide treatment, etc.; a survey of the building and ventilation; and when warranted, sampling and analysis of air. Each case presented is unique in that atypical situations caused agents to accumulate in a building or section of a building. The indoor air problems in these cases were solved by identifying and removing the source of the offending agent and/or improving the ventilation in the building.

Adhesives↗
PubMed1997

Radiolysis of DNA in the presence of a protein studied by HPL-gel chromatography.

The influence of bovine serum albumin (BSA) on the radiolysis of double-stranded DNA was studied by measuring the loss of highly polymerized DNA with HPL-gel chromatography. The scavenger capacity of BSA for OH.-radicals kBSA [BSA] was kept constant. at 7.8 x 10(5) s-1, when DNA (0.1 mg/ml) was irradiated under different gas conditions (air, N2 and N2O), at pH 7 and 5 and with different ionic conditions. The resulting protein radicals react with DNA producing DNA protein crosslinks and DNA double-strand breaks. The yield and the kind of DNA damage depend on the nature of the protein radicals and their association with DNA. High phosphate concentration prevents the association of BSA with DNA and causes a reduction of the protection by BSA against double-strand break-age of DNA. Radiolysis in the presence of BSA in perchlorate solution leads to more strand breakage and less protein crosslinking than in phosphate solution because perchlorate is more chaotropic than phosphate. Changing the pH from 7 to 5 increases the protection by BSA against DNA strand breakage.

Chromatography, High Pressure Liquid↗
PubMed1979

Design and evaluation of a low cost columnar flow ventilation scheme in an operating theatre.

A plenum chamber type ventilating system which produces a column of clean filtered air in an orthopaedic operating theatre has been designed using conventional air conditioning equipment. Its performance has been evaluated by carrying out smoke studies, and air velocity studies, and its cleanliness evaluated by bacteriological sampling. Two hundred and fifty operations involving implants have been conducted since this system has been installed, and the infection has been zero. This paper reports on the performance of this low cost ventilating system.

Air Microbiology↗
PubMed2001

Supine position decreases the ability of the nose to warm and humidify air.

We tested the hypothesis that decreasing nasal air volume (i.e., increasing nasal turbinate blood volume) improves nasal air conditioning. We performed a randomized, two-way crossover study on the conditioning capacity of the nose in six healthy subjects in the supine and upright position. Cold, dry air (CDA) was delivered to the nose via a nasal mask, and the temperature and humidity of air were measured before it entered and after it exited the nasal cavity. The total water gradient (TWG) across the nose was calculated and represents the nasal conditioning capacity. Nasal volume decreased significantly from baseline without changing the mucosal temperature when subjects were placed in the supine position (P < 0.01). TWG in supine position was significantly lower than that in upright position (P < 0.001). In the supine position, nasal mucosal temperature after CDA exposure was significantly lower than that in upright position (P < 0.01). Our data show that placing subjects in the supine position decreased the ability of the nose to condition CDA compared with the upright position, in contrast to our hypothesis.

Adult↗
PubMed2004

Optimization of air protection expenditures on municipal scale.

The application of air protection methods and technologies involves considerable investment and maintenance costs. Thus, to reduce overall expenditures an economic calculation of air pollution control, should be applied. This problem is connected in special way with areas of great population of inhabitants with spatially uneven density, where energetic, technological and domestic emission sources are located. Such calculations are preferred to be used on the town and municipal scale. The maximized ecological effect might be calculated from aggregate mean annual ambient concentration and population density distribution. Aggregate concentration reflects concentrations of all emitted pollutants, being taken into account. As an example, the optimization for Bytom--an industrial town regarded as one of the most heavily polluted in Europe--was carried out due to its energy production facilities. Alternative fuels were taken into consideration. It demonstrates that expenditures of a relatively small percentage of overall energy production costs can make a substantial improvement to the ambient air condition.

Air Pollution↗
PubMed2005

Ozone exposure and mortality: an empiric bayes metaregression analysis.

BACKGROUND: Results from time-series epidemiologic studies evaluating the relationship between ambient ozone concentrations and premature mortality vary in their conclusions about the magnitude of this relationship, if any, making it difficult to estimate public health benefits of air pollution control measures. We conducted an empiric Bayes metaregression to estimate the ozone effect on mortality, and to assess whether this effect varies as a function of hypothesized confounders or effect modifiers. METHODS: We gathered 71 time-series studies relating ozone to all-cause mortality, and we selected 48 estimates from 28 studies for the metaregression. Metaregression covariates included the relationship between ozone concentrations and concentrations of other air pollutants, proxies for personal exposure-ambient concentration relationships, and the statistical methods used in the studies. For our metaregression, we applied a hierarchical linear model with known level-1 variances. RESULTS: We estimated a grand mean of a 0.21% increase (95% confidence interval = 0.16-0.26%) in mortality per 10-microg/m increase of 1-hour maximum ozone (0.41% increase per 10 ppb) without controlling for other air pollutants. In the metaregression, air-conditioning prevalence and lag time were the strongest predictors of between-study variability. Air pollution covariates yielded inconsistent findings in regression models, although correlation analyses indicated a potential influence of summertime PM2.5. CONCLUSIONS: These findings, coupled with a greater relative risk of ozone in the summer versus the winter, demonstrate that geographic and seasonal heterogeneity in ozone relative risk should be anticipated, but that the observed relationship between ozone and mortality should be considered for future regulatory impact analyses.

Air Pollutants↗
PubMed1995

[An outbreak of Pontiac fever due to Legionella pneumophila serogroup 7. II. Epidemiological aspects].

From August 20 to 22, 1994, an outbreak of acute febrile illness occurred in a Training Center building of a company in Shibuya-ku, Tokyo. All 43 trainees attended in two groups and 2 Center staffs were attacked. Illness was self- limiting, generally lasting three days. Though strains of legionellae, isolated from the water of the cooling tower located at the top of the building, were identified as Legionella pneumophila by microplate DNA-DNA hybridization, they failed to agglutinate with antisera against L. pneumophila serogroups 1 through 6. Two strains were sent to the Centers for Disease Control, Atlanta, Georgia, USA, and determined as serogroup 7 of the species. Since the clinical courses agreed with the definition of Pontiac fever by Glick et al. and seroconversion in a patient against the cooling tower strain (EY3698)from 1:16 to 1:256 was determined by indirect fluorescent antibody technique, the epidemic of acute febrile illness was concluded as an outbreak of Pontiac fever due to L. pneumophila serogroup 7. The cooling tower was a cylindrical open style, with volumetric flow rate of 130 liter/min, and was used for air- conditioning exclusively to the third floor of the building. The building equipped no air-inlet, and indoor-air of the training room exchanged at every break time through windows of 168 cm in height and 72 cm in width. The cooling tower was not operated for five days before the Group A trainees checked in the Center on 18 August followed by Group B trainees on 19 August. It was speculated that high atmospheric temperature and stagnation of cooling water during this period would lead L. pneumophila to overly multiply, which could be a source of infection by flowing in through opened windows to the training rooms.

Disease Outbreaks↗
PubMed1999

Reactive oxygen intermediate production by oyster hemocytes exposed to hypoxia

Oysters are frequently exposed to severely hypoxic conditions, especially during summer months. During the summer, there are also large numbers of disease-related oyster mortalities. This research was conducted to determine whether exposure to environmental hypoxia reduces the ability of oyster hemocytes to produce reactive oxygen intermediates (ROIs), an important part of their defense system. Oysters of the species Crassostrea virginica were held in normoxic (P(O)(2)=20.0-20.7 kPa, pH 7.8-8.0) and hypoxic conditions (P(O)(2)=4.0-6.7 kPa, pH 7.1-7.4). In vivo hemolymph variables (P(O)(2), P(CO)(2) and pH) were measured after both 1 hour and 2 days in each treatment to determine the appropriate environment for subsequent hemocyte experiments. Production of reactive oxygen intermediates by hemocytes was measured using luminol-enhanced chemiluminescence (CL). During CL tests, hemocytes were held under the following conditions: air (P(O)(2)=20.7, P(CO)(2)<0.07, pH 7.6), in vivo hemolymph conditions of normoxic oysters (P(O)(2)=5.2, P(CO)(2)=0.27, pH 7.6), and in vivo hemolymph conditions of hypoxic oysters (P(O)(2)=1.47, P(CO)(2)=0.53, pH 7.1). Production of ROIs under hypoxic conditions was 33 % of that under normoxia. This decrease was the result of specific and independent effects of lower oxygen levels and decreased pH. It was not due to any direct effect of CO(2).

Journal Article↗