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Biomedical subjects

C Price

Publications and source records attributed to C Price.

At least 19 recordsLinked to original sources
PubMed2001

Sensitometric evaluation of a new F-speed dental radiographic film.

OBJECTIVE: To compare a new experimental Kodak (Eastman Kodak, Rochester, NY, USA) F-speed dental X-ray film with Ektaspeed Plus and Ultra-speed. METHODS: The three types of film were exposed and processed under standardized conditions. Values of base plus fog, speed, and film contrast were derived. Resolution was compared by a line-pair plate. RESULTS: Under these experimental conditions, the speed of the new film was just into the F-speed range, and a little over twice as fast as Ultra-speed. The Ektaspeed Plus emulsion was somewhat slower than previously recorded when it was first introduced, but around the centre of the E-speed range. Ektaspeed Plus and the new F-speed film had almost identical film contrasts, the F-speed film having slightly greater contrast in the higher density range. Ultra-speed contrast was marginally greater in the lower density range, but was overtaken by both of the other emulsions at higher densities. All three emulsions had low values of base plus fog. Both E- and F-speed films resolved 10 line-pairs per millimetre well, though both emulsions were inferior to Ultra-speed. CONCLUSIONS: The new F-speed film, since marketed as Insight, provides a further saving in radiation exposure, with no evident deterioration in film contrast or resolution.

Absorptiometry, Photon↗
PubMed2001

Identification without naming: a functional neuroimaging study of an anomic patient.

The neural correlates of identification and name retrieval have proved difficult to characterise because both occur highly automatically in normal language processing. Thus, although some evidence points to the left anterior temporal cortex (ATC) as a brain region underlying these functions, its relative role in semantic and lexical retrieval processes is still a matter of debate. Positron emission tomography (PET) was used to measure regional cerebral blood flow responses to famous and non-famous visually presented faces and buildings in a severely anomic patient and in six control subjects, while they were performing a same-different matching task. Because the patient was able to identify the stimuli that he could not name, it was possible to investigate whether the left ATC would respond when identification occurred without name retrieval. Both the patient and the controls activated the left ATC when famous stimuli were compared with non-famous stimuli. This result supports the hypothesis of a predominantly semantic function of the left ATC.

Adult↗
PubMed2000

Monomer, dimer, tetramer, polymer: structural diversity in zinc and cadmium complexes of chelate-tethered nucleobases.

A series of ZnII and CdII complexes of adenine and guanine derivatives containing a diamine tether have been isolated from aqueous solutions and characterised by single crystal X-ray analysis. These studies reveal a wide range of structural types including monomeric, dimeric, tetrameric and polymeric architectures. The extended structures arise from the ability of the ligands to bridge metal ions using the chelating tether in conjunction with N7 of the nucleobase. Additional metal-nucleobase co-ordination is generally observed at the N3-site of the adenine derivatives. With CdII, ethylenediamine-N9-ethylguanine forms an inverted G-tetrad type structure.

Journal Article↗
PubMed2000

Evidence for a link between global lightning activity and upper tropospheric water vapour

Tropospheric water vapour is a key element of the Earth's climate, which has direct effects as a greenhouse gas, as well as indirect effects through interaction with clouds, aerosols and tropospheric chemistry. Small changes in upper-tropospheric water vapour have a much larger impact on the greenhouse effect than small changes in water vapour in the lower atmosphere, but whether this impact is a positive or negative feedback remains uncertain. The main challenge in addressing this question is the difficulty in monitoring upper-tropospheric water vapour globally over long timescales. Here I show that upper-tropospheric water-vapour variability and global lightning activity are closely linked, suggesting that upper-tropospheric water-vapour changes can be inferred from records of global lightning activity, readily obtained from observations at a single location on the Earth's surface. This correlation reflects the fact that continental deep-convective thunderstorms transport large amounts of water vapour into the upper troposphere and thereby dominate the variations of global upper-tropospheric water vapour while producing most of the lightning on Earth. As global lightning induces Schumann resonances, an electromagnetic phenomenon in the atmosphere that can be observed easily at low cost, monitoring of these resonances might provide a convenient method for tracking upper-tropospheric water-vapour variability and hence contribute to a better understanding of the processes affecting climate change.

Journal Article↗
PubMed2000

A cultural effect on brain function.

We present behavioral and anatomical evidence for a multi-component reading system in which different components are differentially weighted depending on culture-specific demands of orthography. Italian orthography is consistent, enabling reliable conversion of graphemes to phonemes to yield correct pronunciation of the word. English orthography is inconsistent, complicating mapping of letters to word sounds. In behavioral studies, Italian students showed faster word and non-word reading than English students. In two PET studies, Italians showed greater activation in left superior temporal regions associated with phoneme processing. In contrast, English readers showed greater activations, particularly for non-words, in left posterior inferior temporal gyrus and anterior inferior frontal gyrus, areas associated with word retrieval during both reading and naming tasks.

Adult↗
PubMed2000

Hepatic resection for colorectal liver metastases: A cost-effectiveness analysis.

OBJECTIVE: To analyze the cost-effectiveness of resection for liver metastases compared with standard nonsurgical cytotoxic treatment. SUMMARY BACKGROUND DATA: The efficacy of hepatic resection for metastases from colorectal cancer has been debated, despite reported 5-year survival rates of 20% to 40%. Resection is confined to specialized centers and is not widely available, perhaps because of lack of appropriate expertise, resources, or awareness of its efficacy. The cost-effectiveness of resection is important from the perspective of managed care in the United States and for the commissioning of health services in the United Kingdom. METHODS: A simple decision-based model was developed to evaluate the marginal costs and health benefits of hepatic resection. Estimates of resectability for liver metastases were taken from UK-reported case series data. The results of 100 hepatic resections conducted in Sheffield from 1997 to 1999 were used for the cost calculation of liver resection. Survival data from published series of resections were compiled to estimate the incremental cost per life-year gained (LYG) because of the short period of follow-up in the Sheffield series. RESULTS: Hepatic resection for colorectal liver metastases provides an estimated marginal benefit of 1.6 life-years (undiscounted) at a marginal cost of 6,742 pound sterling++. If 17% of patients have only palliative resections, the overall cost per LYG is approximately 5,236 pound sterling (5,985 pound sterling with discounted benefits). If potential benefits are extended to include 20-year survival rates, these figures fall to approximately 1,821 pound sterling (2,793 pound sterling with discounted benefits). Further univariate sensitivity analysis of key model parameters showed the cost per LYG to be consistently less than 15,000 pound sterling. CONCLUSION: In this model, hepatic resection appears highly cost-effective compared with nonsurgical treatments for colorectal-related liver metastases.

Analysis of Variance↗
PubMed2000

Abnormal functional activation during a simple word repetition task: A PET study of adult dyslexics.

Eight dyslexic subjects, impaired on a range of tasks requiring phonological processing, were matched for age and general ability with six control subjects. Participants were scanned using positron emission tomography (PET) during three conditions: repeating real words, repeating pseudowords, and rest. In both groups, speech repetition relative to rest elicited widespread bilateral activation in areas associated with auditory processing of speech; there were no significant differences between words and pseudowords. However, irrespective of word type, the dyslexic group showed less activation than the control group in the right superior temporal and right post-central gyri and also in the left cerebellum. Notably, the right anterior superior temporal cortex (Brodmann's area 22 [BA 22]) was less activated in each of the eight dyslexic subjects, compared to each of the six control subjects. This deficit appears to be specific to auditory repetition as it was not detected in a previous study of reading which used the same sets of stimuli (Brunswick, N., McCrory, E., Price, C., Frith, C.D., & Frith, U. [1999]. Explicit and implicit processing of words and pseudowords by adult developmental dyslexics: A search for Wernicke's Wortschatz? Brain, 122, 1901-1917). This implies that the observed neural manifestation of developmental dyslexia is task-specific (i.e., functional rather than structural). Other studies of normal subjects indicate that attending to the phonetic structure of speech leads to a decrease in right-hemisphere processing. Lower right hemisphere activation in the dyslexic group may therefore indicate less processing of non-phonetic aspects of speech, allowing greater salience to be accorded to phonological aspects of attended speech.

Adult↗
PubMed2000

Clinicians' attitudes to recruitment to randomised trials in cancer care: a qualitative study.

OBJECTIVES: To explore attitudes to and problems experienced with recruitment into randomised trials in cancer care. METHODS: In-depth semi-structured interviews with a purposive sample of 20 hospital clinicians in the South West of England identified from 192 participants in a larger postal survey. Interviews were recorded on audiotape and fully transcribed. Data were analysed by comparing transcripts and describing emergent themes. RESULTS: Clinicians do not always find it easy to identify key randomised trials in their area of interest. Even when they identify those trials in which they would like to participate, they are not always able to recruit patients. Although recruitment can be hindered by the time and administration involved and the resources needed, the attitudes of clinicians to research in general, the design of randomised trials, clinicians' concerns regarding individual patients and patients' preferences for different treatments also present major barriers. Other factors of concern include the imposition of strict eligibility criteria and the expense and complexity of monitoring and follow-up. CONCLUSION: Barriers to recruitment depend on the clinicians' individual situations and on a complex combination of factors. Action is needed to promote awareness of randomised trials under way, to ensure that trials address issues of importance, are acceptable to patients and clinicians, and that practical support is provided for participating centres.

Attitude of Health Personnel↗
PubMed2000

Yeast myosin light chain, Mlc1p, interacts with both IQGAP and class II myosin to effect cytokinesis.

MLC1 (myosin light chain) acts as a dosage suppressor of a temperature sensitive mutation in the gene encoding the S. cerevisiae IQGAP protein. Both proteins localize to the bud neck in mitosis although Mlc1p localisation precedes Iqg1p. Mlc1p is also found at the incipient bud site in G(1) and the growing bud tip during S and G(2) phases of the cell cycle. A dominant negative GST-Mlc1p fusion protein specifically blocks cytokinesis and prevents Iqg1p localisation to the bud neck, as does depletion of Mlc1p. These data support a direct interaction between the two proteins and immunoprecipitation experiments confirm this prediction. Mlc1p is also shown to interact with the class II conventional myosin (Myo1p). All three proteins form a complex, however, the interaction between Mlc1p and Iqg1p can be separated from the Mlc1p/Myo1p interaction. Mlc1p localisation and maintenance at the bud neck is independent of actin, Myo1p and Iqg1p. It is proposed that Mlc1p therefore functions to recruit Iqg1p and in turn actin to the actomyosin ring and that it is also required for Myo1p function during ring contraction.

Alleles↗
PubMed2000

Decision making in dual-task environments: analysis of hemispheric competition effects.

Performance degradations in multitasking situations have been reported frequently as a predictable effect of competition that arises from different processing demands whose hemispheric locations are too proximal. This model might be useful in explaining performance deficits in complex workplaces. To test this assertion, a laboratory study was designed to create an analogue of the processing demands required by a tactical decision-making task performed by 24 right-handed men. Vocalization, dichotic listening and decision-making performance were assessed under single- and dual-task conditions. The results were consistent with the predictions from hemispheric competition in the case of dichotic listening but not with vocalization. The results are discussed in terms of their implications for both research and systems design.

Auditory Perception↗