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Biomedical subjects

B E Taylor

Publications and source records attributed to B E Taylor.

At least 19 recordsLinked to original sources
PubMed2004

Responses of benthic fish exposed to contaminants in outdoor microcosms--examining the ecological relevance of previous laboratory toxicity tests.

Previous laboratory studies indicate that coal combustion wastes (a mixture composed of fly ash and other lower volume wastes such as bottom ash; hereafter collectively referred to as ash) adversely affect the health of benthic fish (Erimyzon sucetta; lake chubsucker), but fish in these studies were provided with ample uncontaminated food resources. Because aquatic disposal of ash can also adversely affect food resources for benthic fish, we hypothesized that changes in resources might exacerbate the effects of ash on fish observed in laboratory studies. We exposed juvenile E. sucetta in outdoor microcosms to water, sediment, and benthic resources from an ash-contaminated site or a reference site for 45 days and compared our findings to previous laboratory studies. Benthic invertebrate biomass was nearly three times greater in controls compared to ash microcosms. Total organic content of control sediment (41%) was also greater than in ash sediments (17%), suggesting that additional benthic resources may have also been limited in ash microcosms. Benthic invertebrates isolated from the ash microcosms had trace element concentrations (As, Cd, Co, Cr, Cs, Se, Sr, and V) up to 18 times higher than in weathered ash used in laboratory studies. The concentrations of trace elements accumulated by fish reflected the high dietary concentrations encountered in the ash microcosms and were associated with reduced growth (final mass = 0.07 g) and survival (25%) compared to controls (0.37 g and 67%, respectively). Accumulation of trace elements, as well as reductions in growth and survival, were more pronounced than in previous laboratory studies, suggesting that resource conditions may be important in mediating ash toxicity. Taken together, our studies suggest that ash discharge into aquatic systems is a more serious threat to the health of benthic fish than previously predicted based upon laboratory toxicity tests.

Analysis of Variance↗
PubMed2000

Do semiclassical zero temperature black holes exist?

The semiclassical Einstein equations are solved to first order in epsilon = Planck's over 2pi/M2 for the case of a Reissner-Nordström black hole perturbed by the vacuum stress energy of quantized free fields. Massless and massive fields of spin 0, 1/2, and 1 are considered. We show that in all physically realistic cases, macroscopic zero temperature black hole solutions do not exist. Any static zero temperature semiclassical black hole solutions must then be microscopic and isolated in the space of solutions; they do not join smoothly onto the classical extreme Reissner-Nordström solution as epsilon-->0.

Astronomical Phenomena↗
PubMed2000

The respiratory central pattern generator of Lymnaea: a model, measured and malleable.

Great progress has been made, and continues to be made in our understanding of the neuronal mechanisms underlying respiration in a wide variety of model systems. The central pattern generator (CPG) controlling aerial respiration in the pond-snail Lymnaea is a particularly well-studied model. Using in vitro and semi-intact preparations, the neural circuitry that controls aerial respiration has been characterized as consisting of three identified interneurons. Furthermore, insight has been gained into the behavioural, cellular and synaptic mechanisms by which this circuit controls respiratory rhythmogenesis. It has also been demonstrated that aerial respiratory behaviour can be modified both by experience and by environmental factors. Studies have shown that, in a behavioural hierarchy, respiration is subservient to the whole-body withdrawal response that respiratory behaviour can be modified through operant conditioning, and that respiratory behaviour is altered by hypoxia. Through research on the Lymnaea respiratory CPG we are coming to a better understanding of the construction and malleability of a CPG network. The malleability of this CPG is of particular interest. No longer can neuronal networks underlying respiratory behaviour be considered hard-wired; they have inherent plasticity.

Animals↗
PubMed2000

Use of isolated digestive-gland cells in the study of biochemical and physiological processes in gastropod molluscs.

We describe a method for preparation and maintenance of isolated digestive-gland cells in the abalone, Haliotis kamtschatkana. Viability of the isolated cells was confirmed by the fact that 18 h after preparation the cells exhibited less than 5% staining with trypan blue and actively synthesized glycogen following the addition of glucose substrate. Use of the method in a 15-month study of metabolic activity of the digestive gland of H. kamtschatkana showed significant differences in oxygen consumption of isolated-cell preparations correlated with seasonal differences in somatic and gametogenetic growth, and with relative size of the digestive gland.

Animals↗
PubMed2000

Verbatim: J B-A.

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Anecdotes as Topic↗
PubMed1990

Depurination of plant ribosomes by pokeweed antiviral protein.

Mammalian ribosomes have been shown to be enzymatically modified by ribosomal inactivating protein (RIPs) via specific depurination of rRNA. Here we report that ribosomes isolated from wheat germ contain intact and undepurinated rRNA and are depurinated by pokeweed antiviral protein (PAP). Pokeweed ribosomes isolated under the same conditions are depurinated. Total RNA isolated from pokeweed in the presence of strong denaturants was found to pbe partially depurinated. We conclude that wheat germ ribosomes are resistant to the endogenous RIP, tritin, but are sensitive to PAP and that pokeweed ribosomes can be depurinated by the N-glycosidase activity of endogenous PAP during isolation.

Antiviral Agents↗
PubMed1989

Etoposide compared with the combination of vincristine, doxorubicin, and cyclophosphamide in the treatment of small cell lung cancer.

One hundred and three patients with small cell lung carcinoma were stratified according to stage of disease (47 limited disease, 56 extensive disease) and then randomised to receive etoposide 300 mg/m2 alone for two days or a combination (VAC) of vincristine 1 mg/m2, doxorubicin (Adriamycin) 50 mg/m2, and cyclophosphamide 1000 mg/m2. The drugs were given at three week intervals. Patients were assessed after three cycles of treatment and continued with the same regimen if in complete remission and with the alternative regimen if in partial remission; they were withdrawn if the disease had progressed. Twenty four patients (23%) achieved complete remission and this occurred more often when patients were receiving VAC (19 of 82) than etoposide (5 of 75). There was no difference, however, in overall survival between those initially treated with etoposide and those having combination chemotherapy, whether for limited disease (both 8 months) or extensive disease (7 and 5.5 months). Toxicity was less with etoposide. Survival was disappointing, especially with limited disease, even in patients who showed a complete response to treatment.

Actuarial Analysis↗
PubMed1988

Stimulus factors influencing the identification of voiced stop consonants by normal-hearing and hearing-impaired adults.

The effects of mild-to-moderate hearing impairment on the perceptual importance of three acoustic correlates of stop consonant place of articulation were examined. Normal-hearing and hearing-impaired adults identified a stimulus set comprising all possible combinations of the levels of three factors: formant transition type (three levels), spectral tilt type (three levels), and abruptness of frequency change (two levels). The levels of these factors correspond to those appropriate for /b/, /d/, and /g/ in the /ae/ environment. Normal-hearing subjects responded primarily in accord with the place of articulation specified by the formant transitions. Hearing-impaired subjects showed less-than-normal reliance on formant transitions and greater-than-normal reliance on spectral tilt and abruptness of frequency change. These results suggest that hearing impairment affects the perceptual importance of cues to stop consonant identity, increasing the importance of information provided by both temporal characteristics and gross spectral shape and decreasing the importance of information provided by the formant transitions.

Adult↗
PubMed1987

Cost management techniques. Part II.

Reducing the cost of purchased products and services is of continuing importance to hospital purchasing and materials managers. In the first of three articles, the authors addressed the life cycle costing approach applied to purchasing as a means of evaluating total costs over the life of a product rather than only evaluating quoted prices. Life cycle costing is most appropriate for longer lived products, those with maintenance, repair, and disposal considerations. This article continues the discussion of cost management techniques focusing on ways to identify and manage total costs of purchasing and acquisition. The third article will present integrated cost and value management techniques.

Commerce↗