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PubMed1996

Reconstruction of the glial environment of a photochemically induced lesion in the rat spinal cord by transplantation of mixed glial cells.

It is becoming increasingly apparent that the astrocytic environment is critical to the normal development and functioning of the CNS, and that acute injury to the spinal cord causes destruction of glial cells in addition to neurones and axons. The aims of this study were to assess the viability of reconstructing the astrocytic environment of a cystic spinal cord lesion by transplantation of glial cells and to examine the effect of the transplanted cells on meningeal cell invasion and revascularisation of the lesion and on axonal regeneration. Neonatal rat and kitten mixed glial cells and the CG-4 rat O-2A progenitor cell line were transplanted into a lesion produced in the dorsal funiculus of the rat spinal cord by photochemical infarction. The animals were killed 4 weeks after injury, their cords examined with light and electron microscopy and compared with control animals that were injected with medium alone. Transplantation of all three preparations resulted in increased numbers of astrocytes in the area of Wallerian degeneration cranial to the lesion and within the cyst. Mixed glial cell cultures prepared from neonatal rat forebrain contained cells with in vitro characteristics of type-1 astrocytes, and produced dense clusters of astrocytes that were surrounded by meningeal cells, resulting in a fragmented environment in the cyst. In contrast, glial cell cultures prepared from kitten forebrain and the CG-4 cell line produced cells that filled the cyst with a loose network of fine processes and reduced meningeal cell infiltration of the lesion. The CG-4 cell line significantly increased the density of blood vessels in the centre of the lesion and the number of spared axons present dorsal to the lesion, but none of the preparations significantly increased the number of axons regenerating at the caudal end of the lesion. We conclude that O-2A progenitor-derived astrocytes are more suitable for reconstruction of the glial environment of a cystic lesion in the rat spinal cord than 'type-1 like' astrocytes and would therefore be the cell of choice to engineer to produce factors that promote axonal regeneration.

Animals↗

PubMedDate not supplied

Strategies for "minimal growth maintenance" of cell cultures: a perspective on management for extended duration experimentation in the microgravity environment of a Space station.

How cells manage without gravity and how they change in the absence of gravity are basic questions that only prolonged life on a Space station will enable us to answer. We know from investigations carried out on various kinds of Space vehicles and stations that profound physiological effects can and often to occur. We need to know more of the basic biochemistry and biophysics both of cells and of whole organisms in conditions of reduced gravity. The unique environment of Space affords plant scientists an unusual opportunity to carry out experiments in microgravity, but some major challenges must be faced before this can be done with confidence. Various laboratory activities that are routine on Earth take on special significance and offer problems that need imaginative resolution before even a relatively simple experiment can be reliably executed on a Space station. For example, scientists might wish to investigate whether adaptive or other changes that have occurred in the environment of Space are retained after return to Earth-normal conditions. Investigators seeking to carry out experiments in the low-gravity environment of Space using cultured cells will need to solve the problem of keeping cultures quiescent for protracted periods before an experiment is initiated, after periodic sampling is carried out, and after the experiment is completed. This review gives an evaluation of a range of strategies that can enable one to manipulate cell physiology and curtail growth dramatically toward this end. These strategies include cryopreservation, chilling, reduced oxygen, gel entrapment strategies, osmotic adjustment, nutrient starvation, pH manipulation, and the use of mitotic inhibitors and growth-retarding chemicals. Cells not only need to be rendered quiescent for protracted periods but they also must be recoverable and further grown if it is so desired. Elaboration of satisfactory procedures for management of cells and tissues at "near zero or minimal growth" will have great value and practical consequences for experimentation on Earth as well as in Space. All of the parameters and conditions and procedural details needed to meet all the specific objectives will be the basis of the design and fabrication of cell culture units for use in the Space environment. It is expected that this will be an evolutionary process.

Bioreactors↗

PubMedDate not supplied

Occurrence of Burkholderia cepacia in the hospital environment.

AIM: To determine the prevalence of Burkholderia cepacia from the environment in a regional adult cystic fibrosis (CF) care centre. METHODS: Two hundred and eighty-five environmental samples were taken from inpatient and outpatient environments within the CF centre. Following a non-selective enrichment step, broths were plated onto a selective medium and B. cepacia isolates were confirmed by phenotypic tests and also genotypically by species specific 16S rRNA PCR. RESULTS: B. cepacia was not detected from commonly shared items of equipment, staff hands, staff uniforms or toilets. In addition, the organism was not detected in toilet bowls, even in the B. cepacia unit. With regard to positive environments for B. cepacia, 4/10 (40%) of the outside surfaces and inner rims of patients' plastic disposable sputum collection containers and 4/17 (23.5%) of air from patients' rooms, following physiotherapy, were positive. CONCLUSIONS: All positive samples originated in the B. cepacia segregation area of the inpatient wards and B. cepacia was not detected in the non-cepacia area of the CF centre. Consequently, these two positive sites should therefore be treated as high risk, where organisms may be potentially transmitted from environment to patient. As there is now evidence to suggest differences in the virulence and hence clinical outcome of certain of the genomovars of this organism, this study may be important in highlighting the areas that patients who are B. cepacia positive should avoid, to minimise the risk of transmission and acquisition of this organism within the CF cepacia population. These results indicate that effective infection control procedures are required in patients' rooms following physiotherapy, for prevention of B. cepacia transmission and to avoid the transmission of different genomovar types within CF patients, who are already colonised with this pathogen.

Air Microbiology↗

PubMed2001

Accumulation of 109Cd by second-generation chironominae propagated from wild populations sampled from low-, mid-, and high-saline environments.

Our objective was to determine if second-generation (F2) chironomids propagated from adults of larvae sampled from low-, mid-, and high-saline environments differed in their ability to accumulate cadmium from their environment. Second-generation chironomids cultured from wild populations were exposed to 109Cd at 0, 0.7, and 4.3 ppt salinity for 10 days, at which time survival and amounts of 109Cd accumulated were determined. Cultures included two of Chironomus tentans from a freshwater lake (lake 78; 0 ppt), and the euryhaline C. athalassicus from a mid- (lake 71; 0.7 ppt) and high (lake 56; 4.3 ppt)-saline environment. A laboratory-reared culture of C. tentans was included as a positive control. Species-dependent accumulation of 109Cd occurred; second-generation C. athalassicus cultured from the high-salinity lake survived in the three salinities and accumulated significantly greater amounts of the radiotracer at 0 and 0.7 ppt compared to the second-generation freshwater species, C. tentans. Second-generation C. athalassicus cultured from lake 71 also survived all salinities with 109Cd accumulation tending to be greater than the freshwater species at the mid-salinity range. In contrast, the freshwater species cultured from lake 78 as well as the laboratory-reared culture did not survive the highest salinity of 4.3 ppt and accumulated less 109Cd compared to the species from the high-saline environments. Species-dependent differences in metal accumulation need to be considered in studies that assess metal concentrations in aquatic organisms across an environmental gradient, such as salinity.

Animals↗

PubMed2006

Expert stakeholders' views on the management of human pharmaceuticals in the environment.

Human pharmaceuticals are ubiquitous water contaminants that may have subtle detrimental effects on aquatic organisms, and possibly also on human health. The risks of pharmaceuticals, or pharmaceutically active compounds, remain poorly understood. Awareness of the presence of pharmaceuticals in the environment, coupled with evidence of effects such as fish feminization, however, suggest that precautionary management action to reduce the release of pharmaceuticals to the environment should be considered. The purpose of our study was to evaluate the scope of the issue and possible management strategies from the perspectives of expert stakeholders, drawn from government, academia, and the pharmaceutical and consulting industries, involved in scientific research or policy and management activity, from Canada, the United States, and Europe. Twenty-seven interviewees were asked about their views on management strategies such as pharmaceutical-return programs and incentives for the development of "green" pharmaceuticals. Interviewees generally believed that pharmaceuticals in the environment represented a concern for both human and ecosystem health, although they were more concerned about impacts on aquatic ecosystems. They believed that advanced wastewater treatment technology, education of medical professionals to reduce overprescription, pharmaceutical-return programs coupled with public education, and requirements for all municipalities to have a minimum of secondary wastewater treatment were the most effective management strategies to reduce the environmental impacts of pharmaceuticals. These strategies should be considered by governments interested in managing the risks of human pharmaceuticals in the environment. Combinations of management strategies will likely be most effective in mitigating the risks presented by pharmaceuticals.

Animals↗

PubMed2006

What is known about temperature and complaints in the upper extremity? A systematic review in the VDU work environment.

UNLABELLED: Upper extremity musculoskeletal complaints and disorders are frequently reported among visual display units (VDU) workers. These complaints include cold forearms, hands or fingers. OBJECTIVE: The aim of this systematic review was to gain an insight into the relationship between objective and subjective temperature decrease and musculoskeletal disorders (MSDs) in the upper extremity in a VDU work environment by (internal or external) cooling of the arm and hand. Two questions were formulated: (1) Is a VDU work environment (temperature between 15 and 25 degrees C) associated with temperature decrease of the arm, hand or fingers in healthy subjects? (2) Is there a difference in arm, hand and finger temperature between patients with upper extremity MSDs and healthy subjects in a VDU work environment? METHODS: Through a systematic literature search in six databases between 1989 and October 2005, 327 articles were retrieved and 17 included. RESULTS: Forearm, hand and finger temperature significantly decreases when the ambient temperature (between 15 and 25 degrees C) decreases. The skin temperature in the hand that uses a computer mouse is lower than the other hand in the same ambient temperature. At baseline, no objective temperature differences are found between patient groups and controls, whereas in patients with cold hand complaints, lower skin temperatures are found compared to controls. The association between temperature (changes) in the forearm, hand or fingers during VDU work, and MSDs in the upper extremity is not clear. CONCLUSION: There is no consistent evidence available for the association between upper extremity MSDs and temperature changes in forearm, hand or fingers in an office work environment.

Computer Terminals↗

PubMed1997

Expired air temperature during prolonged exercise in cool- and hot-humid environments.

The purpose of this investigation was to measure expired air temperature under cool- and hot-humid environmental conditions at rest and during prolonged exercise to: (1) establish if significant increases in body core temperature affected expired air temperature, and (2) to determine if the temperature setting for heating the pneumotachometer in an open-circuit system requires adjustment during prolonged exercise tests to account for changes in expired air temperature. Six male distance runners completed two tests in cool-humid [dry bulb temperature (Tdb) 15.5 (SD 1.3) degrees C, wet bulb temperature (TWb) 12.1 (SD 1.4) degrees C] and hot-humid [Tdb 31.6 (SD 0.6) degrees C, TWb 24.9 (SD 0.6) degrees C, black globe temperature (Tg) 34.3 (SD 0.3) degrees C] environments, running at a velocity corresponding to 65% [67.1 (SD 2.82)%] of their maximal oxygen uptake. Rectal temperature and expired air temperatures were compared at rest, and after 30 min and 60 min of exercise for each environment. The main finding of this investigation was a significant (P < 0.05) but small increase in expired air temperature between the 30-min and 60-min measures in the hot-humid environment. No significant differences in expired air temperature were found between the 30-min and 60-min measures in the cool-humid environment. These findings suggest that: (1) expired air temperature is influenced by elevations in body core temperature during prolonged exercise in hot-humid conditions, and (2) that the temperature setting for heating the head of the pneumotachometer (after determining the appropriate temperature through measuring expired air temperature for the set environmental condition) may require adjustment during prolonged exercise trials in hot-humid environmental conditions.

Adult↗

PubMed2006

Bacteriological evaluation of the cardiac surgery environment accompanying hospital relocation.

PURPOSE: Airborne bacteria in the environment are thought to be a cause of postoperative infection. With the relocation of our hospital, the operating room we had used for 35 years was replaced, changing the surgical environment for cardiac operation completely. We conducted this study to evaluate the bacteriological change in the surgical environment between the new and old operating rooms. METHODS: Airborne contaminants in the operating rooms were collected on blood agar plates, and samples of intraoperative salvaged blood from cardiac surgery were drawn from salvaged bags produced by Cell Saver 5 (Haemonetics, Braintree, MA, USA) in both the old (group O) and the new operating rooms (group N). These samples were cultured and evaluated bacteriologically. RESULTS: We collected nine samples of airborne contaminants from both group O and group N. The mean number of isolated bacteria colonies was 5.0 +/- 1.2 in group O, and 2.0 +/- 0.94 in group N (P < 0.001). Bacterial growth was detected in 85% of the salvaged blood samples from group O (n = 20) versus 60% from group N (n = 15) (P = 0.09). The mean bacteria count was 1.9 +/- 2.7 colony-forming units (cfu)/ml in group O versus 0.4 +/- 0.5 cfu/ml in group N (P = 0.032). CONCLUSION: Hospital relocation resulted in an improved operating room environment with less bacterial contamination of intraoperative salvaged blood.

Air Microbiology↗

PubMed2005

Neurophysiological age differences during task-performance in a stereoscopic virtual environment.

In today's society, there is an increasing number of workplaces in virtual environments (VE). But, there are only a few reports dealing with occupational health issues or age effects. The question arises how VR generally interferes with cognitive processes. This interference might have relevant implications for workability and work-efficiency in virtual environments. Event-related potentials are known to reflect different stages of stimulus reception, evaluation, and response. We have established an electroencephalographic (EEG) monitoring, focussing on event-related potentials (N100; mismatch negativity, i.e., MMN) to obtain access to attention dependent and pre-attentive processing of sensory stimuli applied in VE. The MMN is known to be correlated with the ability of subjects to react to an unexpected event. The aim of the present study was to investigate cognitive responses to distracting auditory stimuli in two different age groups in a virtual environment (VE) and in a real environment ("real reality"), and to compare characteristic neurophysiological response patterns. Data show that stimulus detection as given by the N100 amplitude and latency does not differ in both age groups and task conditions. In contrast, the pre-attentive processing as given by the MMN is altered in the VR such as the non-VR condition in an age-related manner. A relevant finding of the present study was that the age related differences seen in the non-VR condition were not strengthened in VR.

Adult↗

PubMed2005

Genetic and environmental influences on adolescents' perceptions of current family environment.

Previous studies of the genetic and environmental components of the Family Environment Scale (FES) have typically reported that scales relating to familial acceptance are moderately to strongly genetically influenced while measures of control are more environmentally influenced. These reports relied on retrospective recall, which is not as reliable as recall of current environment. To investigate the genetic contribution to contemporaneous perceptions of one's rearing environment, the responses on the FES of 471 17-year-old male twins (141 complete MZ twin pairs, 73 complete DZ twin pairs, 43 incomplete twin pairs) participating in the Minnesota Twin-Family Study (MTFS) were analyzed. Individual FES scales were generally modestly to moderately heritable. Unlike previous research, we did not find evidence that measures of control/structure were less heritable than measures of acceptance/support. These findings support a genetic basis of perceptions of one's family environment and indicate that reports of control/structure may be more genetically influenced than previously believed based on retrospective reports.

Adolescent↗

PubMed2005

Origin, occurrence, and biodegradation of long-side-chain alkyl compounds in the environment: a review.

Long-side-chain alkyl compounds, such as those present in oil and oil products, either of natural or of anthropogenic origin or released by industrial activities, are a ubiquitous group of chemicals in the environment. Among them, long-side-chain alkylmonocycloalkanes, alkylbenzenes, and alkyl organic sulfur compounds are largely found in fossil fuels while long-side-chain alkylbenzene sulfonates and alkylphenols are released into the environment primarily due to domestic activities. The present article briefly summarizes the advances that have occurred in this field in terms of the identity, abundance, possible origin and significance of these long-side-chain alkyl compounds found in the environment. In addition, the susceptibility to biodegradation and the fate of these chemicals in the environment are discussed.

Biodegradation, Environmental↗

PubMed2026

Expression dynamics of mCry3A and eCry3.1Ab transgenes in Bt corn hybrids across growth and environments.

In 2017 and 2018, studies were conducted in Iowa, US across three environments with a history of greater than expected corn rootworm injury i.e., greater than one node of injury to (US EPA 2009) and one environment without rootworm injury, and at different growth stages, to determine the expression levels of mCry3A and eCry3.1Ab transgenes in the roots of different Bt corn hybrids namely the molecular stack (MZIR098), breeding stack (MIR604 × 5307), 5307 and MIR604. ELISA results showed that expressions of both mCry3A and eCry3.1Ab transgenes, were higher in the MZIR098 molecular stack and breeding stack (MIR604 × 5307), than the MIR604 and 5307 at V3 and VT growth stages over both years. To protect the roots from feeding damage by the corn rootworm larvae, expression of the transgenes must be high at the V3 growth stage. The expression of the transgene was significantly impacted by the stage of plant growth while the environments with greater than expected corn rootworm injury did not impact expression of the transgenes. It was found that the expression of mCry3A and eCry3.1Ab transgenes were high at the V3 plant growth stage compared to the VT growth stage. Stacking two or more genes together in the same plant such as the molecular and breeding stacks have the potential to protect roots in environments with higher-than-expected damage and slow down the evolution of resistance in field populations of rootworms.

Zea mays↗

PubMed2006

Gene by environment interaction in asthma.

Asthma is a chronic inflammatory disease of the airways that is highly prevalent in the Western world. It is a genetically complex disease caused by multiple genetic and environmental factors, which may interact. Genetic research has recently incorporated environmental factors to investigate gene by environment interaction, and the first examples of gene by environment interaction in asthma have been reported. Linkage analyses indicate that one or more genes on chromosome 5q interact with environmental tobacco smoke in infancy in asthma development. Several candidate genes have been consistently shown to interact with the environment. These include the innate immunity genes CD14 and Toll-like receptor 4, and microbial exposures, as well as the detoxifying gene family glutathione-S-transferase and environmental tobacco smoke exposure and air pollutants. Gene by environment interaction is important in asthma pathogenesis, and future studies should take the interaction of both factors into account.

Air Pollutants↗

PubMed1992

Work environment functions in small enterprises in Sweden.

In Sweden, a governmental commission has formed new strategies concerning the work environment with the aims of reducing employee absenteeism and re-employing those individuals who have already left employment as a result of bad working conditions. The main features in this new approach are: strengthening of the legislation; a responsibility for work injury costs; and a distinct rehabilitation responsibility. In this paper the authors discuss how these proposals suited the constraints and facilities of small enterprises, employing less than 50 persons. The results are based on interviews carried out with company directors, safety representatives and labour inspectors. The interviews revealed that the company directors had a negative attitude towards both the strengthening of legislation and responsibility for work injury costs. It was also revealed that the small companies lack both knowledge of how a good environment can be created and the state of their own work environment. It seems that the small companies cannot handle work environment questions in a systematic way without comprehensive education and training or without seeking expert assistance outside the company.

Journal Article↗

PubMed1983

Environment of the aromatic chromophores of acyl carrier protein.

Acyl carrier protein contains two phenylalanines (residues 28 and 50) and one tyrosine (residue 71). The environment of these chromophores was assessed using first-derivative spectroscopy to examine the uv absorption spectrum of acyl carrier protein in detail. In particular, the phenylalanine absorption maxima were perturbed from the water spectrum, and experiments with model systems suggested that the phenylalanines of acyl carrier protein reside in an environment more similar to acetonitrile than water. The spectrum in the phenylalanine region resulted from the tertiary folding of the protein since these features disappeared in the absorption spectrum of the denatured acyl carrier protein. Tyrosine-71 appears to be a partially buried residue based on the native minus denatured ACP difference spectrum as well as solvent and thermal perturbation spectra. The attachment of a fatty acid to acyl carrier protein resulted in a shift in the absorption spectrum of tyrosine-71 consistent with this chromophore being in a more hydrophobic environment in the acylated protein. The apolar environment of the aromatic amino acids in acyl carrier protein suggests that they are structural components of the hydrophobic sequences that comprise the fatty acid-binding domain of this protein.

Acyl Carrier Protein↗

PubMed1982

Effects of postoperative environments following dorsal hippocampal lesions on dendritic branching and spines in rat occipital cortex.

Male Long-Evans rats sustained bilateral dorsal hippocampal lesions or were sham-operated when 31 days old. They were reared thereafter in either an 'enriched' (EC) or an 'impoverished' (IC) environment for one month. The effects of lesion and rearing conditions were measured on dendritic branching and spines in layer V pyramidal cells of area 17 by using a concentric ring analysis and by counting the number of spines on 50 micron segments of basilar dendrites. Hippocampal lesions significantly decreased the branching and the number of spines in both EC and IC rats. In contrast to what was observed in most behavioral studies, in which the effects of the postoperative environment were even larger in animals with lesions than in control animals, the present experiment showed that the cytological measures were affected by postoperative rearing conditions only in sham-operated rats (EC greater than IC). It is suggested, therefore, that the morphologic processes underlying the effects of the environment on behavioral recovery after hippocampal lesions can hardly be located in layer V pyramidal cells of area 17, which is considered as one of the most sensitive to environment in intact animals.

Animals↗

PubMed1995

Ophthalmic microsurgical robot and associated virtual environment.

An ophthalmic virtual environment has been developed as part of a teleoperated microsurgical robot built to perform surgery on the eye. The virtual environment is unique in that it incorporates a detailed continuum model of the anatomical structures of the eye, its mechanics and optical properties, together with a less detailed geometric-mechanical model of the face. In addition to providing a realistic visual display of the eye being operated on, the virtual environment simulates tissue properties during manipulation and cutting and the forces involved are determined by solving a mechanical finite element model of the tissue. These forces are then fed back to the operator via a force reflecting master and so the surgeon can experience both the visual and mechanical sensations associated with performing surgery. The virtual environment can be used to enhance the images produced by the camera on the microsurgical slave robot during surgery and as a surgical simulator in which it replaces these images with computer graphics generated from the eye model.

Computer Graphics↗

PubMed1988

Effects of a hybrid maternal environment on brain growth and corpus callosum defects of inbred BALB/c mice: a study using ovarian grafting.

The corpus callosum of many but not all BALB/c mice is either abnormally small or absent. The basis for the defect is hereditary, but the proportion of mice expressing the anomaly can be modified by changing the early environment. The present study investigated the effects of an F1 hybrid maternal environment, which is known to promote better fetal development than an inbred environment, on body and brain growth in BALB/c and on the incidence of the corpus callosal defect. Ovarian follicle cells from BALB/cWah (albino) mice were grafted into pigmented F1 hybrid, BALB/cWah, and pigmented BALB female hosts of comparable age which were subsequently mated to BALB/cWah males. Groups of unoperated BALB/cWah and pigmented BALB dams were included as controls. Data from 111 litters were analyzed. Results showed that BALB mice with F1 mothers had heavier bodies at birth, weaning, and 100 days of age and heavier brains at 100 days than those with either grafted or ungrafted BALB mothers. The effects at birth were evident across all litter sizes (2 to 11), but those at weaning and 100 days were seen only in litters of more than 5 or 6. Neither the F1 hybrid maternal environment nor the grafting procedure itself appeared to influence the incidence or expression of the corpus callosal defect. About 22% of the offspring from each of the three groups (ungrafted BALB, grafted BALB, and grafted F1) showed a defective corpus callosum.

Agenesis of Corpus Callosum↗