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Biomedical subjects

R A Simpson

Publications and source records attributed to R A Simpson.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1987

Good Manufacturing Practice. Environmental requirements.

What does Good Manufacturing Practice, GMP, mean in terms of Central service organisation? It can be seen as embodying all aspects which cover the quality, safety and performance of articles that will either be produced or reprocessed, for use in the care of patients.

Central Supply, Hospital↗
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↗
PubMed1982

Synthesis and biological activity of some very hydrophobic superagonist analogues of luteinizing hormone-releasing hormone.

The effect of increased hydrophobicity at position 6 of luteinizing hormone-releasing hormone (LH-RH) has been investigated by the incorporation of a series of 15 very hydrophobic, unnatural D-amino acids at this position. The unnatural amino acids studied can be considered analogues of phenylalanine with carbocyclic aromatic side chains consisting of substituted phenyl (e.g., 2,4,6-trimethylphenyl, p-biphenyl) or polycyclic aromatic (e.g., naphthalene, anthracene) units. When enzymatic resolution (subtilisin Carlsberg) of the most hydrophobic amino acids failed, the racemic amino acids were incorporated, and the diastereomeric LH-RH analogues were resolved by preparative high-performance liquid chromatography. The analogues were synthesized by the solid-phase technique. All of the synthetic compounds were very potent LH-RH superagonists, but [6-(3-(2-naphthyl)-D-alanine)]LH-RH, [6-(3-(2-naphthyl)-D-alanine), 7-(N alpha-methylleucine)]LH-RH and [6-(3-(2,4,6-trimethylphenyl)-D-alanine)]LH-RH appear to be among the most potent LH-RH agonist analogues yet reported when tested in a rat estrus cyclicity suppression assay designed to show the paradoxical antifertility effects of these compounds [ED50 approximately 7 x 10(-8) g; twice daily in saline]. These analogues are twice as potent as [D-Trp6,ProNHEt9]LH-RH in this assay system (i.e., approximately 200 times the potency of LH-RH).

Amino Acids↗
PubMed1980

Comparison of hexachlorophane and chlorhexidine powders in prevention of neonatal infection.

The protective effect of treating the skin of newborn infants with powders containing 1% chlorhexidine or 0.33% hexachlorophane was compared. Each was equally effective in preventing colonisation and infection by Staphylococcus aureus. In contrast, the skin became profusely colonised by coagulase-negative staphylococci, irrespective of the powder used. Venous blood concentrations of chlorhexidine were low or undetectable in the few infants whose blood was analysed.

Chlorhexidine↗
PubMed1978

A hospital epidemic caused by gentamicin-resistant Klebsiella aerogenes.

In the 15 months, February 1976 to April 1977, more than 241 patients became colonized with a strain of Klebsiella aerogenes, capsular serotype K2, resistant to most antibiotics. Urinary tract infection was the most common clinical manifestation but bacteraemia and, occasionally, infections of other sites were encountered. The main reservoir of the epidemic klebsiella was the gut, urine and skin of colonized patients. Gut carriage among staff was very uncommon. The most susceptible patients were elderly males, with debilitating illnesses and urinary tract abnormalities, especially if they were catheterized or receiving antibiotics. Likely vehicles for spread were the hands of staff, and contaminated bedpans and urinals. Control measures were directed at these factors. At the end of April 1977 no new cases had occurred for 3 months in the ward in which the outbreak began, and which had been the main focus of infection, and only 5 patients in the affected hospitals were known to be colonized by the epidemic klebsiella.

Cross Infection↗