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Biomedical subjects

R A Simpson

Publications and source records attributed to R A Simpson.

At least 19 recordsLinked to original sources
PubMed1991

Using guidelines, policies and standards: are we in control?

For the hospital microbiologist, the use of guidelines, policies and standards are an integral part of their professional duties. Both patient-related and laboratory activities involve awareness of specific procedures and the use of equipment or products which have been accepted as appropriate for a particular purpose. The means by which policy is formulated, the guidance available and the standards specified, differ widely from country to country. In the UK, there are few legal requirements or statutory regulations in this area. In consequence, there may be some differences in both the nature and the method of implementation of policies from hospital to hospital. There is increasing concern that legislation and standards produced not only by the UK but also by Europe may impose regulations on infection control and laboratory practice and in particular that such mandatory controls may have adverse effects. These are variously perceived as specifying inappropriate standards, inhibiting clinical freedom and stifling innovation. Such concern is embodied in the question 'are we in control?'.

Clinical Protocols↗
PubMed1988

Bacteriuria and bacteraemia in patients with long-term indwelling catheters--a domiciliary study.

Men with indwelling catheters and men and women with suprapubic catheters were studied in their homes. Urine and blood were cultured and body temperature recorded after every catheter change. Nearly all patients had infected urine after 4 weeks of catheterisation, and all had bacteriuria after longer periods, usually with a mixture of organisms. Culture on selective media revealed a wider range of organisms than was detected on routine C.L.E.D. and blood agar with antibiotic sensitivity disks, but routine culture gave adequate information for clinical purposes. Bacteraemia was demonstrated after 20 of 197 changes of urethral catheter and after one of 19 changes of suprapubic catheter; but no patient had pyrexia or other symptoms. However, two had rigors on other occasions. When assessing "risk factors" for blood-stream infection in catheterised patients, it is important to record the total incidence of bacteraemia, asymptomatic as well as symptomatic.

Bacteria↗
PubMed1988

Comparison of a hydrocolloid dressing and paraffin gauze in the treatment of venous ulcers.

In-patients with venous leg ulcers showed increased healing rates with a hydrocolloid dressing (Granuflex), as compared with a traditional paraffin gauze dressing (Jelonet), in a randomized sequential crossover trial, although the difference was not statistically significant. Bacteriological studies showed that the hydrocolloid dressing favoured growth of both aerobes and anaerobes in significantly greater numbers compared with paraffin gauze. Heavy bacterial colonization had no effect on the healing rates of the ulcers. Granuflex is said to produce an anaerobic environment--survival of Pseudomonas aeruginosa, a strict aerobe, under Granuflex dressings, makes this seem unlikely.

Aged↗
PubMed1987

Bladder irrigation with chlorhexidine for the prevention of urinary infection after transurethral operations: a prospective controlled study.

The value of postoperative bladder irrigation with the antiseptic agent chlorhexidine was assessed in a randomized prospective controlled study of men after transurethral operations. In patients with sterile preoperative urine the incidence of postoperative bacteriuria was 12.8 per cent, compared to 36.7 per cent in control patients. The difference is significant (chi-square 5.54, p less than 0.02). On the other hand, chlorhexidine irrigation did not eliminate pre-existing infection. Small amounts of chlorhexidine were demonstrated in the blood of some patients. There was no evidence of damage to the bladder and no toxic side effects.

Administration, Intravesical↗
PubMed1986

Colonization by gentamicin-resistant Staphylococcus epidermidis in a special care baby unit.

Babies entering a special care baby unit during a 3-month period were studied prospectively for colonization by gentamicin-sensitive and -resistant coagulase-negative staphylococci (CNS). Gentamicin-resistant isolates were characterized by biotyping, antibiotic sensitivity pattern and phage-typing. All the babies studied became colonized with gentamicin-resistant CNS and often with multiple strains. Gentamicin-sensitive CNS usually appeared first and predominated, but gentamicin-resistant staphylococci could be detected by enrichment culture at a median time of 1 day, and, by direct culture at a median time of 4 days. Similar strains were found in the environment and nasal carriage was detected in 60% of the staff of the unit by enrichment culture. The gentamicin-resistant strains were all resistant to benzylpenicillin and other antibiotics. No particular pathogenic strain could be identified, but clusters of colonizations by distinguishable strains were noted. Biotype SVI was frequently encountered, particularly among clinically significant isolates.

Anti-Bacterial Agents↗
PubMed1986

Topical nonsteroidal antipsoriatic agents. 1. 1,2,3,4-Tetraoxygenated naphthalene derivatives.

On the basis of previous observations that both 2,3-dihydro-2,2,3,3-tetrahydroxy-1,4-naphthoquinone (oxoline, 1) and 6-chloroisonaphthazarin (2) had demonstrated antipsoriatic activity in vivo, a series of structural derivatives of 2 were prepared and examined in the Scholtz-Dumas topical psoriasis bioassay. Of these six (5, 6, 9a, 10, 11a, 11b), the most effective compound was found to be 6-chloro-1,4-diacetoxy-2,3-dimethoxynaphthalene (RS-43179, lonapalene, 11a). An extensive series of 1,2,3,4-tetraoxygenated naphthalenes (16-74) incorporating variations of the ester, ether, and aryl substituents were prepared as analogues of 11a to examine the structural requirements for activity and were screened in vivo as inhibitors of arachidonic acid induced mouse ear edema, a topical bioassay capable of detecting 5-lipoxygenase inhibitors. Net lipophilicity, hydrolytic stability, and ring substitution play significant roles in determining the observed in vivo activity. Lonapalene (11a) is currently in clinical development as a topically applied nonsteroidal antipsoriatic agent.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1986

Selective and differential medium for the primary isolation of members of the Proteeae.

A new differential and selective medium for the isolation of members of the Proteeae, PIM (Proteeae isolation medium) agar, was developed and evaluated. The medium relies on the ability of all members of the Proteeae (with the exception of a very few Morganella morganii strains) to produce a dark brown pigment in medium containing DL-tryptophan. An additional differential property, tyrosine degradation, was also demonstrated by the medium. Members of the Proteeae appeared as dark brown colonies with a halo of clearing of fine tyrosine crystals when cultured on PIM agar. Occasional strains of Citrobacter sp. and Pseudomonas aeruginosa may degrade tyrosine, but none has the ability to produce dark brown pigmentation on PIM agar. Quantitative recovery studies showed that the addition of 5 mg of clindamycin per liter suppressed gram-positive bacteria without inhibiting any strains of the Proteeae. The addition of 100 mg of colistin per liter made the medium highly selective for strains of the Proteeae, but approximately 10% of the strains were not isolated, thus making this formulation unsuitable for general surveys of the occurrence of members of the Proteeae. PIM agar should aid the investigation of episodes of cross infection caused by members of the Proteeae and the isolation of the new species of the Proteeae recently described.

Clindamycin↗
PubMed1984

Experimental infection and hydrogel dressings.

The prolonged use of a hydrogel (polyacrylamide) dressing on circular 1 cm skin defects was tested in a rat experimental model. The rate of healing and changes in bacterial content following inoculation of 1 X 10(8) Staphylococcus aureus, Escherichia coli or Pseudomonas aeruginosa were measured. Wounds inoculated with Staph. aureus or E. coli prior to polyacrylamide occlusion did not have delayed wound contraction and healing and numbers of organisms were falling at 10 days. Wounds inoculated with Ps. aeruginosa showed a delay in healing with a large increase in organisms (greater than 1 X 10(10] after 10 days occlusion. Prolonged wound occlusion by hydrogel dressings may aid in healing by secondary intention but the presence or growth of pseudomonas indicates that frequent changes of dressings should be made.

Animals↗
PubMed1983

Does the addition of disinfectant to urine drainage bags prevent infection in catheterised patients?

The value of adding chlorhexidine to urine drainage bags of male patients treated with indwelling catheters after prostatectomy and other transurethral operations was assessed in a randomised, prospective, controlled was assessed in a randomised, prospective, controlled study. Chlorhexidine kept the contents of all drainage bags sterile, but the frequency of urinary infection in the chlordexidine group (51%) did not differ significantly from that in the control group (45%). Most infections were endogenous, caused by organisms which probably came from the patient's own urethra. It was concluded that the method has no value in urology units where standards of catheter care and closed drainage are properly maintained. Controlled studies in other types of catheterised patients are needed, especially when the risks of cross-infection are high.

Catheters, Indwelling↗