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Biomedical subjects

C Burgess

Publications and source records attributed to C Burgess.

125 records · Page 7Linked to original sources
PubMed1982

Radial haemolysis for the detection of rubella antibody in acute postnatal rubella.

One hundred and forty-eight sera from 101 cases of acute postnatal rubella were examined by the radial haemolysis (RH) technique currently recommended by the Public Health Laboratory Service of the United Kingdom. In 75 cases the date of onset of rash was known. No sera were RH positive until the third day after the onset of rash and one serum was still negative at 9 days. By 10 days all sera gave a zone of at least 10 mm. The antibody response detected by RH appears later than that detected by haemagglutination inhibition (HI). Thirty-nine of the 101 cases could be diagnosed by seroconversion or a significant rise in titre using the HI test (diagnosis of the remainder depending upon rubella-specific IgM tests). Using the RH test this figure rises to 48 but in ten of these cases reliance on RH would have meant a delay in diagnosis. The results also indicate that many more sera would need to be tested for rubella-specific IgM if the RH test was used instead of the HI test for evaluating possible cases and contacts of rubella.

Acute Disease↗
PubMed1978

Rapid reversed-phase high-performance liquid chromatographic analysis of steroid products.

The optimisation of conditions for the application of reversed-phase high-performance liquid chromatography (HPLC) to the analysis of steroid products is discussed. The influence of temperature and flow-rate on column efficiency are described. At 60 degrees, the reduced velocity required to give maximum efficiency, is approximately twice that found at room temperature, allowing faster through-put. (hv) curves are reported for 5-micron Spherisorb-ODS and Hypersil-ODS material for corticosteroids at 60 degrees. On-column injection techniques are discussed and data presented, showing that for corticosteroids on-column loop injection can be efficient as septum injection using the techniques described.

Betamethasone↗
PubMedDate not supplied

Age vs Alzheimer's: a computational model of changes in representation.

Previous research has demonstrated that the language of older adults leads to denser representations in a high dimensional model of memory than does the language of younger adults (Conley & Burgess, in press), and thus that density in the model (HAL or the hyperspace analogue to language) may constitute a useful metric in comparing memory for younger and older adults. This paper extends the previous research by examining the role of density in semantic representations that emerged from the language generated by adults with Alzheimer' s and comparing the results with age-matched normal controls. We found that, just as older adults have denser representations in semantic space than do younger adults, adults with Alzheimer's have still denser representations than normal older adults. These results support the hypothesis that greater density, normally associated in the model with good semantic depth, may in fact reach a "saturation point" and affect retrieval in older adults and especially adults with Alzheimer's.

Age Factors↗
PubMedDate not supplied

Withdrawal of fenoterol and the end of the New Zealand asthma mortality epidemic.

In response to the evidence that fenoterol was a major cause for the second epidemic of asthma deaths in New Zealand, the Department of Health severely restricted its availability, thereby allowing an 'experiment in prevention' to be undertaken. These regulatory actions, which effectively removed fenoterol from the market in New Zealand, were associated with a sudden and marked reduction in asthma mortality, providing further evidence for a causative role of fenoterol in the epidemic of asthma deaths in New Zealand.

Administration, Inhalation↗
PubMedDate not supplied

Human studies on the bioavailability of a quaternary ammonium compounds, tiemonium iodide and tiemonium methosulphate.

Five volunteers were administered capsules containing 14C-labelled tiemonium iodide and 4 volunteers received capsules of 14C-labelled tiemonium methosulphate. Serum, urine and faecal levels of tiemonium were measured. The percentage of the dose absorbed was determined after a further labelled intravenous injection into 3 of the volunteers. The drug appeared to be poorly absorved, as expected for quaternary ammonium compounds, but there was no difference in the bioavailability of these two tiemonium salts.

Administration, Oral↗
PubMedDate not supplied

Phonological and semantic information in word and nonword reading in a deep dyslexic patient.

Deep dyslexia is diagnosed when brain-injured, previously literate adults make reading errors that include hallmark semantic paralexias (e.g., reading HEART as BLOOD) and are also impaired at reading nonwords (e.g., FRIP). The diversity of these symptoms have led most researchers to conclude that there are multiple sources of impairment in this syndrome and that one of the most critical is a failure to process phonological information at a sublexical level. The patient (SD) reported in this study fits the deep dyslexia profile to the extent that she makes several semantically related reading errors. She also shows the classic frequency and image ability effects of the syndrome. However, as we report, she does read some nonwords correctly and she shows a strong advantage for naming when phonemic cues are presented. We discuss the performance of SD, on these preliminary tasks, in terms of a phonological selection impairment.

Dyslexia↗
PubMedDate not supplied

Age effects in a computational model of memory.

Previous research demonstrates that semantic priming is relatively unaffected by age (Chiarello, Church, & Hoyer, 1985; Howard, 1988). To determine how age might affect representations in the HAL model of memory, the authors gathered text from older and younger adults and generated a global co-occurrence matrix for each. An analysis demonstrated that, as in humans, there was little difference in measures of semantic priming between memory matrices constructed from the two corpora. However, the authors discovered that semantic word neighborhoods generated by the older adult corpus were denser than corresponding neighborhoods derived from the younger adult corpus. This result has implications for changes in the semantic representation of words due to the aging process.

Adult↗