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Biomedical subjects

S M Bell

Publications and source records attributed to S M Bell.

At least 109 records · Page 6Linked to original sources

Treatment with gentamicin monitored by serum antibiotic assay.

Gentamicin is very widely accepted as the most effective antibiotic for treatment of a number of serious Gram-negative infections, but one disadvantage associated with its use is the risk of toxicity particularly affecting the eighth nerve. An account is given of eight years' experience with this antibiotic in which obvious ototoxicity was avoided in hospitalized patients in whom gentamicin treatment was monitored by assay of the residual amounts of antibiotic present in the serum. The relationship between accumulation of gentamicin in patients with renal impairment and ototoxicity is discussed. Attention is drawn also to the presence of an increased risk of ototoxicity in patients, particularly the elderly, in whom mild-to-moderate degrees of renal impairment may be overlooked. In such patients modification of the frequency of the dose of gentamicin is necessary and a schedule of treatment based on the results of assay of residual serum levels of gentamicin is given.

Aged↗

Quantitative throat-swab culture in the diagnosis of streptococcal pharyngitis in children.

A striking difference in the detection of a heavy growth of Streptococcus pyogenes in throat swabs taken from 1054 children with pharyngitis compared with those from 462 normal children was demonstrated when a standardised technique of quantitative culture was used. In patients with pharyngitis 71% of the isolates were heavy whereas a heavy culture was obtained in only 1-7% of healthy children. Also, a significant correlation between the clinical observations suggestive of streptococcal pharyngitis and the results of culture was confined to those patients whose throat swabs yielded a heavy growth of streptococci. It is concluded that bacteriological examination is of value as a diagnostic test only when the results of culture are quantitatively assessed.

Age Factors↗

Relevance of "significant bacteriuria" to aetiology and diagnosis of urinary-tract infection.

28 of 74 female domiciliary patients who presented with urinary-tract symptoms did not fulfil the usually accepted laboratory criterion required for confirmation of urinary-tract infection (i.e., a urinary bacterial viable count in excess of 100 000/ml). The progress of the disease was similar in non-bacteriuric and bacteriuric patients. In addition, a significant proportion of the bacteriuric group did not show the response to therapy expected from the results of in-vitro tests of antibiotic sensitivity and urinary antibacterial activity. To explain these findings, it is postulated that bacteria may not be primary pathogens in uncomplicated urinary-tract infection even where "significant bacteriuria" is demonstrated.

Adolescent↗

New satellitism test for isolation and identification of Haemophilus influenzae and Haemophilus parainfluenzae in sputum.

A new satellitism test designed to facilitate the isolation and identification of Haemophilus influenzae and Haemophilus parainfluenzae is described. In the basal medium, nicotinamide adenine dinucleotide is incorporated at a concentration of 0.2 mug per ml, an amount adequate for H. influenzae but not for H. parainfluenzae. Two disks are placed on the surface of the medium, one disk being impregnated with 60 mug of hemin and the other with 15 mug of nicotinamide adenine dinucleotide. Under these conditions, H. influenzae strains grow around the hemin disk only and the majority of H. parainfluenzae grow around the nicotinamide adenine dinucleotide disk. This procedure gives results which are more clear cut than other established methods, especially in sputum culture.

Bacteriological Techniques↗

Two types of information in picture memory.

It is assumed that recognition memory for pictures is based on two types of information. The first is information about specific details in a picture. The process of encoding this type of information is identified with what N. H. Mackworth and others have termed looking at "informative areas" in pictures. The second informational component is designated as "general visual information." Two experiments were carried out investigating (a) the extent to which recognition responses to pictures are based on specific detail vs. general visual information, (b) whether the amount of specific detail information may be manipulated by varying the complexity of a target picture, and (c) the rate at which the two types of information are acquired. The results indicate that the rate of encoding specific details varies with the number of potential informative areas in a pictures and, given that a detail is encoded, memory performance is not substantially affected by target complexity, exposure time, or presence or absence of a mask.

Acoustic Stimulation↗