SEARCH · PubMed Health

Results for “Environment, Controlled”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 577 records · Page 32Linked to original sources

PubMed1983

Effect of cold exposure on various sites of core temperature measurements.

Rectal, esophageal, auditory canal, gastrointestinal tract, and sublingual temperature were recorded on five young Caucasian males who, in an environment of -32 degrees C and 11-km/h wind, sat during one 90-min exposure and walked on a treadmill at 2.9 km/h during another. The clothing permitted cooling of their torsos while giving adequate protection to their extremities. Control exposures involved subjects sitting in still air at 24-26 degrees C dressed only in thermal underwear. In the control environment all of the internal body temperatures measured gave comparable and consistent values; however, cold exposure affected the various sites differently. Esophageal temperatures fluctuated rapidly as a result of subjects swallowing cold saliva. Sublingual temperatures were below the lower limit of a clinical thermometer, possibly because of facial cooling. Auditory canal temperatures were low, perhaps also because of facial cooling. Rectal temperatures were high as were the gastrointestinal tract temperatures, due perhaps to local heat production in response to cold stimulation. Metabolic rate increased initially in the cold and again toward the end of the cold exposure.

Body Temperature↗

PubMed2000

Research based prevention strategies. Management of latex allergy in the workplace.

1. Facility-wide goals should combine primary and secondary prevention approaches to reduce or minimize contact and aerosolized natural rubber latex exposure for clients, employees, and visitors. 2. Potential immune sensitization or continuation of symptoms of latex allergy can be reduced by using screening questionnaires to recognize potential risk factors or history of latex allergy; documentation of a referral to a physician for diagnosis; standardization of facility-wide general product selection; and work environment controls by discriminate, appropriate, informed glove choices. 3. Discriminate glove choices of nonlatex, non-powedered, or low allergen/non-powdered natural rubber latex gloves have become the primary proactive strategy adopted by hospitals and clinics to create a latex minimized environment.

Evidence-Based Medicine↗

PubMedDate not supplied

Helicopters: extending the prehospital transportation system.

Early efforts to upgrade the prehospital care system were directed toward improved communications, training, education, and ground transport. Increased sophistication within these components of the integrated emergency medical services system prompted the need for categorizing and formally designating trauma centers. With the designation of comprehensive trauma centers to serve not only local areas but macroregional trauma needs, the requirements for faster transport in a medically controlled environment to cover greater distances became evident. Thus, the helicopter has emerged as the appropriate prehospital transport vehicle to fulfill such needs. What remains is the stimulus and mechanism to fully integrate all of these components into a medically controlled, cost-effective, regionally coordinated system.

Aircraft↗

PubMed1995

Altered vasoactivity in the early diabetic eye: measured in the isolated perfused rat eye.

The effect of 4 weeks streptozotocin-induced diabetes on ocular vascular resistance responses to noradrenalin (NA), adrenalin (A), phenylephrine (PHE), isoproterenol (ISOP), prostaglandin F2 alpha (PGF2 alpha). 5-hydroxytryptamine (5-HT) and angiotensin II (ANG II), was determined using a newly-developed, isolated, arterially-perfused rat eye preparation, by comparing responses from control and diabetic eyes. After extensive preliminary experiments to establish optimum parameters, the ophthalmic artery of enucleated control and diabetic rat eyes was cannulated and the retinal and uveal vasculature perfused at a constant flow with Na(+)-Krebs solution after streptozotocin-induced diabetes had been established for 4 weeks. The eyes were maintained in an environment-controlled organ bath. Perfusion pressure was monitored as increasing log M concentrations of agonists were added to the perfusate. Total ocular resistance could be calculated from knowledge of flow and pressure. In control eyes, NA, A, PHE, PGF2 alpha, and 5-HT all produced dose-dependent increases in total vascular resistance, with the following order of potency: NA = A > 5-HT > PHE = PGF2 alpha at 10(-4) M. The ocular circulation was not sensitive to isoproterenol and angiotensin II. In diabetic eyes responses to NA, A, PGF2 alpha and 5-HT were altered. Diabetic responses to NA and A had lower thresholds with larger resistance increases at low concentrations. However, the rate of increase in resistance with concentration was more gradual in diabetic eyes so that at 10(-4) M control responses were larger. Diabetic resistance responses to PGF2 alpha had the same threshold as in control eyes, but were greater in magnitude with an earlier peak at 10(-4) M. In contrast diabetic resistance responses to 5-HT were reduced, peaked at a lower resistance at 10(-4) M, but had the same threshold as those in the control eye. Basal vascular resistances in control: 3.14 +/- 0.32 mmHg min microliter-1 (n = 28), and diabetic eyes: 3.44 +/- 0.19, mmHg min microliter-1 (n = 36), were not significantly different. Vasoactivity in the early diabetic eye is disturbed with the effective balance between different agonists altered in favour of catecholamines at physiological concentrations. This may be related to the early changes in blood flow and oxygen distribution already reported in the rat eye, as well as changes to autonomic function. The isolated perfused rat eye is a valuable technique for investigating such vascular reactivity in animal models of retinal disease.

Angiotensin II↗

PubMed1999

Effect of nebulized albuterol on circulating leukocyte counts in normal subjects.

Nebulized beta 2-receptor agonists may cause neutrophil demargination and result in misleading total circulating leukocyte counts (WBCs) in patients with acute bronchospasm. Varying underlying adrenergic stimulation in these patients also makes interpretation of these data difficult. This study examined the direct effect of these agents on the measured WBCs of healthy adults without evidence of bronchospasm or illness. A prospective, blinded, randomized study of 30 healthy volunteers (aged 18-50 years) was performed in a controlled environment. Subjects were excluded if they were pregnant, had a known underlying medical disorder or have had a prior reaction to albuterol or similar medications. Participants in the study were given either a nebulized albuterol treatment or nebulized normal saline (control group). Leukocyte counts were then obtained before and after treatments. Paired data were analysed using a one-tailed t-test while considering an increase of 40% in WBCs to be significant, P = 0.05, and beta = 0.10. Mean leukocyte counts were 5.9 (+/- 1.2) before treatment as compared to 6.0 (+/- 1.3) after albuterol nebulization. Using the coefficient of variance of WBCs in normal humans as c. 50% (6000 +/- 3000 cells mm-1) we were unable to demonstrate a significant difference in variation in post-nebulized leukocyte counts between the control group and the nebulized albuterol group. While there is concern that the treatment of patients experiencing acute bronchospasm with beta 2 agonists may result in factitious elevations in peripheral leukocyte counts, were found no direct effect of these agents on measured counts in normal subjects.

Adolescent↗

PubMed2005

Mucosal immunity and self-tolerance in the ocular surface system.

This paper articulates a new working hypothesis that explains many of the pathophysiological conditions described under the common rubric "dry eye" as altered states of mucosal immune regulation. A central principle of mucosal immune physiology is that the parenchymal tissues at the effector sites, i.e., the sites at which secretory antibodies are produced, maintain local signaling milieus that support differentiation of IgA+ plasmablasts and survival of IgA+ plasmacytes. These local signaling milieus also support robust regulatory networks that maintain tolerance to commensual microbes, benign antigens, and parenchymal autoantigens. The regulatory networks are mediated by cycles of interactions between successive generations of dendritic cells, which normally mature with tolerogenic functions, and regulatory T cells, which normally reinforce the system's ability to generate new tolerogenic dendritic cells. The systemic endocrine environment controls expression of the local signaling milieu in the mammary gland and in the prostate and male urethral glands. Emerging evidence indicates that the local signaling milieu in the lacrimal gland also is determined, in part, by the systemic endocrine environment. This working hypothesis suggests explanations for the excess incidence of Sjogren syndrome among women and for the mechanisms of several different immunophysiological states in addition to Sjogren syndrome that, like Sjogren syndrome, are associated with the classical symptoms and signs of dry eye. It also comprises a promising rationale for specific new approaches to therapy.

Journal Article↗

PubMed2003

Self-efficacy and its interrelation with family environment and metabolic control in Turkish adolescents with type 1 diabetes.

OBJECTIVE: To explore the relationship between self-efficacy, family environment (cohesion and organization) and metabolic control. RESEARCH DESIGN AND METHODS: A total of 100 adolescents with diabetes were assessed on a single occasion. Eligibility criteria were an age range of 11-18 yr, diagnosis of type 1 diabetes of at least 1 yr duration, and ability to complete the questionnaire unaided. Adolescents completed self-efficacy and family environment questionnaires. Metabolic control was assessed by HbA1c. Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) Version 10.0. Independent paired t-tests and Pearson's correlation coefficient were used as test methods. RESULTS: Boys and girls were comparable on self-efficacy, and self-efficacy scores were quite satisfactory for both boys and girls. There was a significant positive correlation between self-efficacy and family cohesion in girls, but self-efficacy was not related to the family environment (cohesion and organization) and metabolic control in the total sample. CONCLUSION: In the present study, there was no relationship between self-efficacy, family environment, and metabolic control in the total sample, but in girls, self-efficacy and family cohesion was positively correlated.

Adolescent↗

PubMedDate not supplied

Simultaneous measurement of 19 components in serum-containing animal cell culture media by fourier transform near-infrared spectroscopy.

Animal cell cultures generate maximal amounts of desired products when maintained in a controlled environment with low and constant concentrations of nutrients and wastes. Traditionally this has involved slow addition of glucose and glutamine; however, recent studies have indicated that a number of low concentration amino acids are required to prevent initiation of apoptosis. Therefore, optimal control of animal cell cultures will likely require measurement of a large number of chemical components. We present here the evaluation of a near-infrared spectroscopic (NIRS) monitoring scheme to quantify 19 cellular nutrients and wastes in culture medium with and without serum. The components include glucose, lactate, ammonia, pyruvate, glutamine, and 14 other amino acids. Spectroscopic calibrations were generated for a synthetic version of a standard culture medium (DMEM) in which the concentrations of 17 DMEM components and ammonia and lactate were varied in a random fashion. This randomization provides a stringent evaluation of the measurement scheme. Reasonably accurate measurements of these 19 components could be accomplished in the absence or presence of 10% horse serum by volume with percent errors ranging from 3% to 37%. Analytes with concentrations as low as 0.3 mM could be reliably quantified. The presence of serum, when properly included in the calibration, has little effect on measurement error. These results provide an important step toward application of NIRS for monitoring the large number of varying components of animal cell cultivations.

Amino Acids↗

PubMed2002

Mapping of a thermo-sensitive earliness per se gene on Triticum monococcum chromosome 1A(m).

An earliness per se gene, designated Eps-A(m) 1, was mapped in diploid wheat in F(2) and single-seed descent mapping populations from the cross between cultivated (DV92) and wild (G3116) Triticum monococcum accessions. A QTL with a peak on RFLP loci Xcdo393 and Xwg241, the most distal markers on the long arm of chromosome 1A(m), explained 47% of the variation in heading date (LOD score 8.3). Progeny tests for the two F(2:3) families with critical recombination events between Xcdo393 and Xwg241 showed that the gene was distal to Xcdo393 and linked to Xwg241. Progeny tests and replicated experiments with line #3 suggested that Eps-A(m) 1 was distal to Xwg241. This gene showed a large effect on heading date in the controlled environment experiments, and a smaller, but significant, effect under natural conditions. Eps-A(m) 1 showed significant epistatic interactions with photoperiod and vernalization treatments, suggesting that the different classes of genes affecting heading date interact as part of a complex network that controls the timing of flowering induction. Besides its interactions with other genes affecting heading date, Eps-A(m) 1 showed a significant interaction with temperature. The effect of temperature was larger in plants carrying the DV92 allele for late flowering than in those carrying the G3116 allele for early flowering. Average differences in heading date between the experiments performed at 16 degrees C and 23 degrees C were approximately 11 days ( P < 0.001) for the lines carrying the Eps-A(m) 1 allele for early flowering but approximately 50 days ( P < 0.0001) for the lines carrying the allele for late flowering. The large differences in heading time (average 80 days) observed between plants carrying the G3116 and DV92 alleles when grown at 16 degrees C, suggest that it would be possible to produce very detailed maps for this gene to facilitate its future positional cloning.

Journal Article↗

PubMed2004

Development and swimming behavior of Medaka fry in a spaceflight aboard the Space Shuttle Columbia (STS-107).

A space experiment aimed at closely observing the development and swimming activity of medaka fry under microgravity was carried out as a part of the S*T*A*R*S Program, a space shuttle mission, in STS-107 in January 2003. Four eggs laid on earth in an artificially controlled environment were put in a container with a functionally closed ecological system and launched on the Space Shuttle Columbia. Each egg was held in place by a strip of Velcro in the container to be individually monitored by close-up CCD cameras. In the control experiment, four eggs prepared using the same experimental set-up remained on the ground. There was no appreciable difference in the time course of development between space- and ground-based embryos. In the ground experiment, embryos were observed to rotate in place enclosed with the egg membrane, whereas those in the flight unit did not rotate. One of the four eggs hatched on the 8th day after being launched into space. All four eggs hatched in the ground unit. The fry hatched in space was mostly motionless, but with occasional control of its posture with respect to references in the experimental chamber. The fry hatched on ground were observed to move actively, controlling their posture with respect to the gravity vector. These findings suggest that the absence of gravity affects the initiation process of motility of embryos and hatched fry.

Animals↗

PubMed1981

Temperature dependence of ethanol depression in mice.

The relationship between environmental temperature, body temperature and ethanol depression was investigated in male C57BL/6J mice. Animals were injected with ethanol (3.6 g/kg) or saline and placed in an experimental or normal room temperature (control) environment. Environmental temperatures from 12-37 degrees C significantly influenced rectal temperature, sleep-time and wake-up brain ethanol concentrations. The rectal temperatures of ethanol-treated animals ranged from 1.5 degrees C greater to 11.3 degrees C lower than their matched saline controls, supporting indications that ethanol impairs normal thermoregulation. Sleep-time decreased up to 43% and wake-up brain ethanol concentrations increased as rectal temperature decreased from approximately 38-32 degrees C. More severe hypothermia after ethanol (rectal temperature less than 29 degrees C) increased sleep-time and decreased wake-up brain ethanol concentrations. These results indicate that sleep-time and brain sensitivity to ethanol vary with rectal temperature in accordance with predictions based on membrane expansion and partition theories of anesthesia and the anticipated anesthetic-like actions of severe hypothermia.

Animals↗

PubMed2006

Confounding factors in water EMG recordings: an approach to a definitive standard.

This work presents a study on the influence of the aqueous environment on the surface EMG (sEMG) signal recorded in bipolar montage from the abductor pollicis brevis muscle, when only the forearm is immersed in water. Ten men, 30.1+/-4.0 (mean +/- SD) years old, performed ten 2-s 40% MVC isometric contractions of the abductor pollicis brevis muscle in two controlled environments (air and water, at a temperature of 32 degrees C). They were always equipped with electrodes protected with a waterproof adhesive tape. No significant variations (paired Wilcoxon test) due to the environments were observed in the median frequency of the power spectrum (MDF) and in the root mean square (RMS) value of the sEMG signal. These results allow us to assess the methodological criteria to properly record sEMG signals in water and provide the basis to explain different findings obtained by other authors.

Adult↗

PubMed2004

Performance of small evacuated canisters equipped with a novel flow controller for the collection of personal air samples.

Small evacuated canisters have become more common in industrial hygiene personal sampling in recent years. The smaller canisters necessitate a low flow rate to ensure a full-shift air sample can be collected. Evaluation of small evacuated canisters compared to sorbent sampling methods is essential to ensure that the canisters accurately monitor airborne contamination. This data, in a controlled environment, will provide practitioners with valuable reference information when considering air-sampling campaigns. Six 300-mL evacuated canisters were used to collect 6-hour breathing zone samples of styrene on volunteers in a large exposure chamber. The canisters were specially designed with a capillary flow controller developed at McGill University in the mid-1990s. Based on the geometry of the capillary the airflow into the canisters was controlled to a low flow rate, approximately 0.3 mL/min. This low sampling flow rate allowed for the use of small-volume canisters as personal samplers to collect styrene vapors. Charcoal tubes and diffusive badges were simultaneously used to collect side-by-side samples for comparison. In addition, an online gas chromatograph (GC) documented the concentration in the chamber throughout the duration of the exposure. The three methods did not disclose any significant statistical difference when compared to the online GC values and to each other. In addition, linear regression analysis between the charcoal tubes and the canisters resulted in a correlation (R(2) > 0.95). An evaluation of the bias and precision (overall uncertainty) of the capillary-canister method, charcoal tubes, and diffusive badges found them to be within criteria established by European Committee for Standardization 482. The results indicate that the capillary-canister sampling device can be an acceptable alternative to sorbent samplers as a personal sampler providing reliable results that are representative of exposures.

Adsorption↗

PubMed2006

Predicting phosphorus availability from soil-applied composted and non-composted cattle feedlot manure.

Prediction of phosphorus (P) availability from soil-applied composts and manure is important for agronomic and environmental reasons. This study utilized chemical properties of eight composted and two non-composted beef cattle (Bos taurus) manures to predict cumulative phosphorus uptake (CPU) during a 363-d controlled environment chamber bioassay. Ten growth cycles of canola (Brassica napus L.) were raised in pots containing 2 kg of a Dark Brown Chernozemic clay loam soil (fine-loamy, mixed, Typic Haploboroll) mixed with 0.04 kg of the amendments. Inorganic P fertilizer (KH2PO4) and an unamended control were included for comparison. All treatments received a nutrient solution containing an adequate supply of all essential nutrients, except P, which was supplied by the amendments. Cumulative P uptake was similar for composted (74 mg kg-1 soil) and non-composted manures (60 mg kg-1 soil) and for the latter and the fertilizer (40 mg kg-1 soil). However, the CPU was significantly higher for organic amendments than the control (24 mg kg-1 soil) and for composted manure than the fertilizer. Apparent phosphorus recovery (APR) from composted manure (24%) was significantly lower than that from non-composted manure (33%), but there was no significant difference in APR between the organic amendments and the fertilizer (27%). Partial least squares (PLS) regression indicated that only two parameters [total water-extractable phosphorus (TPH2O) and total phosphorus (TP) concentration of amendments] were adequate to model amendment-derived cumulative phosphorus uptake (ACPU), explaining 81% of the variation in ACPU. These results suggest that P availability from soil-applied composted and non-composted manures can be adequately predicted from a few simple amendment chemical measurements. Accurate prediction of P availability and plant P recovery may help tailor manure and compost applications to plant needs and minimize the buildup of bioavailable P, which can contribute to eutrophication of sensitive aquatic systems.

Animals↗

PubMed1996

Reversal of Barrett's esophagus with acid suppression and multipolar electrocoagulation: preliminary results.

BACKGROUND: Barrett's esophagus is a premalignant lesion for esophageal adenocarcinoma. This study tests the hypothesis that re-injury of the metaplastic the epithelium in an acid-controlled environment will result in reversal of Barrett's to squamous epithelium. METHODS: Patients with at least 2 cm of Barrett's esophagus were treated with omeprazole, and half the circumference of the Barrett's was treated with multipolar electrocoagulation (MPEC); the other half served as an internal control. After 6 months, the remaining Barrett's esophagus was treated with MPEC. RESULTS: Twenty-four hour esophageal pH of less than 4 averaged 1.8% on a mean dose of 56 mg/day of omeprazole. Ten patients had visual and biopsy elimination of the targeted section of Barrett's esophagus after an average of 2.5 MPEC sessions. The remainder of the Barrett's esophagus is being treated in 9 patients; currently 5 have no evidence of Barrett's. CONCLUSIONS: The combination of control of esophageal acid exposure and reinjury of the metaplastic epithelium reverses Barrett's esophagus to squamous epithelium as determined by endoscopy and biopsy.

Aged↗

PubMed1980

The influence of single daily heroin injections on drinking patterns in the rat.

The licking behavior of male Sprague-Dawley rats individually housed in a controlled environment with a 12-h lighting schedule and food and water available ad libitum was recorded every 30 min. Body weight and 24-h fluid intake were measured daily at 0800 hours, after which subcutaneous injection was given. When saline (0.3 mL/100 g) was injected as a control for 5 days, only a small percentage of total daily licking behavior occurred during the light hours. Heroin hydrochloride (5 or 20 mg/kg) was then injected for the next 10 days. The first injection of heroin caused a cessation of licking behavior followed by a bout of daytime drinking so that the percentage occurring during the light hours increased. This "stimulated" licking occurred progressively earlier as heroin injections were repeated. Total daily fluid intake and rate of weight gain during heroin treatment were not significantly different from those in the control period, although they tended to be less with the higher dose. Withdrawal from this dose led to mild transient hyperirritability (Teiger scores) during the first 36 h and another change of licking behavior. The results suggest that the diurnal licking pattern of rats drinking ad libitum is especially vulnerable to disruption by heroin.

Administration, Oral↗

PubMed2001

Decreased density of neurons in the medial preoptic nucleus and increased testicular weights for rats exposed perinatally to an 0.5 Hz Rotating Magnetic Field.

Pregnant Wistar rats were exposed to either 0.5 Hz Rotating Magnetic Fields (50 microT to 300 microT or 1.5 mT to 3.0 mT) or to sham field or control environments for 3 days before to 3 days after the day of birth. The adult male offspring that had been exposed perinatally to the RMF displayed significantly heavier testicle weights but fewer neurons within the medial preoptic nucleus (MPO) and caudal ventromedial hypothalamus relative to sham field controls (effect size about 30%). There was no statistically significant difference between the two ranges of RMF intensities for these measures. RMF-exposed rats relative to sham-field exposed rats did not differ with respect to spleen weights, body weights, or mounting (reproductive) activity. The heavier testicle weights replicated previous studies and suggest that permanent, selective alterations in neuronal density can also occur subsequent to perinatal exposure to relatively weak, extremely low frequency magnetic fields.

Animals↗

PubMed1987

Relationship between SO2 dose and growth of the pea aphid, Acyrthosiphon pisum, on peas.

A series of experiments was carried out in controlled environment cabinets to investigate the effects of SO(2) dose on the mean relative growth rate (MRGR) of pea aphids, Acyrthosiphon pisum, feeding on the pea plant, Pisum sativum. There was a significant linear increase in the MRGR of aphids feeding on SO(2)-fumigated plants, relative to control aphids feeding on plants in charcoal-filtered air. The increase in MRGR reached a maximum of 11% at SO(2) concentrations between 90 and 110 nl litre(-1). MRGR declined at higher SO(2) concentrations until above 220 nl litre(-1) it was below that of the controls. The dose-response curve is discussed in relation to reported changes in the nitrogen metabolism of plants subject to air pollution, the response of aphids to host plant nitrogen and possible toxic effects of high concentrations of SO(2) on the aphid.

Journal Article↗