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Biomedical subjects

A Hedge

Publications and source records attributed to A Hedge.

18 recordsLinked to original sources
PubMed2005

Distribution of pesticide residues within homes in central New York State.

Residues for 17 pesticides were analyzed in 41 households in central New York State that represented farm, rural, and urban houses. Samples were taken in both summer and winter of 2000-2001 from the same households from four locations; family room carpet; adjacent smooth floor; flat tabletop surface; and settled dust collected in a Petri dish on a tabletop. Pesticide residues were analyzed to identity factors that influence both the transport into and the redistribution of pesticides in the indoor environment. Differences were observed between the various pesticides and pesticide classifications relative to location within and between households as well as by season. Variations in the pesticide residues were related to a number of factors. Higher residues were observed in the farm households, particularly in summer, with the highest amount observed for chloropyrifos in carpet (33 microg/m2). For many pesticides, the frequency of detection and the amount of residues were higher in summer, which relates to usage patterns in agriculture and horticulture; however, larger amounts of insecticides such as mecoprop, resmethrin, and tetramethrin were found on flat surfaces in winter, indicating household use and possible redistribution within the home. Distribution patterns suggest that routines within a household may cause high variation in residues; these practices include indoor pets and treatment for fleas and ticks, use of termiticides, and fastidiousness of occupants. Frequency of pesticide detection was highest in carpet for both summer and winter for all households, indicating that carpets hold pesticides over time. Adsorbent fibrous materials such as textiles hold pesticides by macro- and micro-occlusion in their complex structures. Amounts of pesticide residue were higher in carpets than on smooth floors, particularly for rural farm households where the farmer was a certified pesticide applicator. The maximum amount of pesticide residue on a smooth floor surface was 13.6 microg/m2 malathion while the maxima on wiped surfaces and in settled dust were 1.8 microg/m2 2, 4 D and 3 microg/m2 pendimethalin, respectively. Physical properties of individual pesticides such as vapor pressure influenced the distribution of the pesticide within the households. Evidence of volatilization of pesticides and redeposition on surfaces was observed, indicating that this is a mechanism for contamination of surfaces in addition to adsorption on airborne particles and tracking. High residues in winter are evidence that closure of households in winter that reduces ventilation results in redistribution of pesticides within households.

Dust↗
PubMed2001

Analytical method development for 18 pesticides in house dust and settled residues using SEC, SPE, TMS methylation, and GC-MS.

An analytical method is developed to analyze eighteen pesticides in carpet dust and also dust that has settled on surfaces in order to determine the potential exposure of children to pesticide residues. For nonacid pesticides, the extract after centrifugation and filtration is cleaned up using size-exclusion chromatography (SEC) and then analyzed by gas chromatography (GC) coupled with a mass spectrometer (MS). The best solvent for extraction is ethyl acetate-cyclohexane (3:1). The recoveries of spiked nonacid pesticides from 2 g of dust are between 72% and 110% with a variation between 4.2% and 25.6%, and the detection limit is 10 to 50 ng/g dust, depending on the pesticide. For acid pesticides, the dust is extracted with a saturated Ca(OH)2 solution, centrifuged, cleaned up by polyvinylbenzene/polystyrene-type solid-phase extraction cartridges, and methylated with trimethylsilyldiazomethane (TMS). Acid pesticides on filter paper samples are extracted with acidified acetone (3 mM H3PO4) and methylated with TMS. Methylation with TMS is fast and easy to perform. Methyl esters of the pesticides are completely separated and detected at low levels by GC-MS in the selective ion monitoring mode. The average recoveries of pesticides from 2 g of dust are between 81% and 104%. The average recoveries of pesticides spiked on filter paper are between 88% and 113%. A capillary column with a stationary phase of trifluoropropylmethyl polysiloxane gives the best separation and sensitivity for most pesticides on the GC-MS.

Carboxylic Acids↗
PubMed2000

Where are we in understanding the effects of where we are?

This paper briefly reviews research studies of interest to environmental ergonomists. It includes some recent work on the health effects of office lighting, especially the effects of daylighting, fluorescent lighting and full-spectrum lighting. It also covers studies of indoor air quality in offices, especially investigations of localized air filtration and the sick building syndrome. It argues the value of a systematic, ergonomics approach to designing the built environment.

Environment Design↗
PubMed1999

Effects of keyboard tray geometry on upper body posture and comfort.

The effects of a downward-tilting (DT) keyboard tray on wrist posture, seated posture and self-assessed musculoskeletal discomfort were investigated in a field experiment. Thirty-eight professional office workers were studied. A pretest assessed how they typed using either a conventional keyboard on a desk or on an articulating keyboard tray, and with or without wrist rests. Workers were randomly allocated to a control (n = 15) or test group (n = 23) that used their existing keyboard in a DT system. A post-test was conducted 3 weeks later. Results showed no significant changes in wrist posture, seated posture or reports of musculoskeletal discomfort for the control group, and approximately 50% of typing wrist movements put the hand in a neutral zone. There were significant improvements in wrist posture, seated posture and upper body musculoskeletal discomfort for the test group using the DT system. Over 80% of typing wrist movements put the hand into a neutral zone with the DT arrangement. Reactions to using a conventional keyboard on a DT system were positive.

Adult↗
PubMed1998

Chemical sensitivity and the immune system: a paradigm to approach potential immune involvement.

This paper approaches the issue of chemical sensitivity and the immune system though a consideration of established environmentally-induced immune alterations which have particular relevance to the broader topic of chemical sensitivity. Additionally, the report discusses the potential problems associated with prior narrow evaluation strategies for the assessment of environmentally-induced inflammation. A combined approach to assessment drawing upon biomarkers of both the immune and neurological systems is suggested. Such an approach recognizes the key roles which mediators of these two systems play in facilitating host inflammatory responses. The paper concludes with a discussion of the types of specific immune alterations which, from a mechanistic perspective, are likely to be involved with any linkage of chemical sensitivity to the immune system.

Environmental Exposure↗
PubMed1996

Toxicological considerations in evaluating indoor air quality and human health: impact of new carpet emissions.

This review article considers evidence regarding the toxicological impact of new carpet emissions on indoor air quality and human health. It compares emissions data from several studies and describes the dominant compounds found in those emissions. The toxicity of each these compounds is assessed for animal and human data, with a focus on inhalation exposure. Data for acute and chronic exposures are presented, and synergistic effects are considered. Differences and similarities between health responses caused by toxicity and/or by immunological reactions are discussed. Possible neurogenic pathways and associations between these and immune changes are considered as they might relate to inflammatory-based human reactions. Additionally, factors affecting human odor responses are described. The roles that a variety of psychological factors may also play in the etiology of potentially related phenomena, such as the sick building syndrome, pathogenic illness, and multiple chemical sensitivity, are considered. Gaps in the literature are identified within the article and suggestions for future research are offered. In particular, it is noted that few, if any, prior studies have evaluated both neurogenic and immune-mediated inflammation status within the same study. Based on the present information available, it is concluded that under normal environmental circumstances, VOC emissions from new carpets are sufficiently low such that they should not adversely affect indoor air quality or pose significant health risk to people.

Air Pollutants↗
PubMed1996

Oncogenicity studies of the new serotonin (5-HT)3-receptor antagonist ramosetron in mice and rats.

Oncogenicity studies of ramosetron ((R)-5-[(1-methyl-3-indolyl)carbonyl]-4,5,6,7-tetrahydro-1H-benzimidazol e hydrochloride, CAS 132907-72-3, YM060), a new compound having serotonin (5-HT)3 receptor antagonist activity, were carried out in male and female mice and rats. Six groups (two control and four treated) of B6C3F1 mice and F344 rats were given YM060, dissolved in distilled water, once daily by oral intubation at doses of 0, 1, 10, 30 and 100 mg/kg/d. Toxicokinetics indicated that sufficient exposure of the animals to the test material was achieved during the oncogenicity studies. Cmax and AUC of YM060 at 100 mg/kg/d were in the range of 3-5 micrograms/ml and 8 micrograms.h/ml in mice, 1-5 micrograms/ml and 7-16 micrograms.h/ml in rats, respectively. The administration of YM060 resulted in a slightly increased mortality rate among female rats treated with 30 or 100 mg/kg/d, particularly during the Weeks 38-87. Body weights of the high-dosed male and female rats during the Weeks 36 to 96 were significantly decreased when compared to controls. An approximately 30% suppression of body weight gain was recorded during Weeks 36-96 for both male and female rats, and 15% suppression of body weight gain was recorded during Weeks 0-104 for male mice. There was no evidence of a treatment-related effect on the incidence of any tumor or tumor type, and there were no non-neoplastic findings considered to be related to the administration of YM060. All microscopic changes seen in mice and rats were of the usual type commonly occurring in untreated aged B6C3F1 mice and F344 rats. In conclusion, there was no evidence of an oncogenic effect of YM060 in mice and rats.

Animals↗
PubMed1995

Effects of lensed-indirect and parabolic lighting on the satisfaction, visual health, and productivity of office workers.

A pre- and post-renovation survey evaluated the reactions of office workers to two office lighting systems: a parabolic downlighting system and a ceiling suspended, lensed-indirect uplighting system. Questionnaire data on work content, perception of ambient environmental conditions (including office lighting), work-related health symptoms, job stress, job satisfaction, and self-reported productivity, and environmental data on illumination, air temperature, and relative humidity were collected. The lensed-indirect lighting system was more favourably rated on several subjective lighting impressions scales, and for computer work workers reported fewer screen glare problems, and fewer and less frequent problems with tired eyes and eye focusing. Productivity was less hindered by the lensed-indirect lighting, and satisfaction with office lighting and ratings of lighting quality were significantly higher for this system. These reactions were not associated with any differences in levels of illumination between the lighting systems. Ratings of lighting satisfaction and lighting importance were inversely related. Overall, some two-thirds of workers indicated a preference for working under the lensed-indirect lighting system.

Adult↗
PubMed1995

Wrist postures while keyboarding: effects of a negative slope keyboard system and full motion forearm supports.

Video-motion analysis was used to analyse hand/wrist posture for subjects typing at a 101-key QWERTY keyboard on a 68 cm high worksurface. Three conditions were tested: subjects typed at the keyboard without arm support, subjects typed with adjustable full motion forearm supports, and subjects typed with an adjustable negative slope keyboard support system. The average declination of the negative slope keyboard support chosen by subjects was 12 degrees below horizontal, which flattened the angle of the key tops. Ulnar deviation was comparable in all conditions and averaged 13 degrees for the right hand and 15 degrees for the left hand. Full motion forearm supports did not significantly affect any postural measures. Dorsal wrist extension averaged 13 degrees when typing with or without the full motion forearm supports, but this was reduced to an average -1 degree with the use of the negative slope keyboard support system. Subjects chose to sit at a distance of 79 cm from the computer screen when using the negative slope keyboard system compared with 69 cm without this.

Adult↗
PubMed1994

The effects of alternative smoking policies on indoor air quality in 27 office buildings.

The effect of alternative smoking policies, which prohibited or restricted smoking, on indoor air quality was studied in 27 air-conditioned office buildings. Carbon monoxide, carbon dioxide, respirable particulates, formaldehyde, ultraviolet particulate matter (u.v.PM), nicotine, air temperature, relative humidity and illumination were measured at eight sample sites in each building. Smoking policy had no effect on carbon monoxide, carbon dioxide, relative humidity, formaldehyde, air temperature or illumination for open office areas. It did have an effect on levels of respirable suspended particulates, ultraviolet particulate matter and nicotine.

Air Conditioning↗
PubMed1985

Comparison of health problems related to work and environmental measurements in two office buildings with different ventilation systems.

A cross sectional survey investigating "building sickness" was carried out in two buildings with similar populations of office workers but differing ventilation systems, one being fully air conditioned with humidification and the other naturally ventilated. The prevalence of symptoms related to work was assessed by a questionnaire administered by a doctor. A stratified, randomly selected sample of workers was seen (84% response). Building sickness includes several distinct syndromes related to work, most of which were significantly more common in the air conditioned building than the naturally ventilated building--namely, rhinitis (28% v 5%), nasal blockage and dry throat (35% v 9%), lethargy (36% v 13%), and headache (31% v 15%). The prevalence of work related asthma and humidifier fever was low and did not differ significantly between the two buildings. An environmental assessment of the offices was performed to attempt to identify possible factors responsible for the differences in the prevalence of disease. Globe temperature, dry bulb temperature, relative humidity, moisture content, air velocity, positive and negative ions, and carbon monoxide, ozone, and formaldehyde concentrations were all measured. None of these factors differed between the buildings, suggesting that building sickness is caused by other factors.

Air Conditioning↗