Effects of superoxide on nitric oxide-dependent N-nitrosation reactions

Recent studies have demonstrated that nitric oxide (NO) in the presence of superoxide (O2-) may mediate mutagenesis via the N-nitrosation of DNA bases followed by nitrosative deamination to yield their hydroxylated derivatives. We have found that phorbol myristate acetate (PMA)-activated extravasated rat neutrophils (PMNs) will N-nitrosate 2,3-diaminonaphthalene (DAN) to yield its highly fluorescent nitrosation product 2,3-naphthotriazole (triazole) via the L-arginine dependent formation of NO. Addition of SOD enhanced triazole formation suggesting that O2- production may inhibit the N-nitrosating activity and thus the mutagenic activity of inflammatory PMNs. The objective of this study was to assess the role of superoxide as a modulator of NO-dependent N-nitrosation reactions using PMA-activated PMNs as well as a chemically defined-system that generates both NO and superoxide. We found that PMA-activation of PMNs reduced found that PMA-activation of PMNs reduced the amount of N-nitrosation of DAN by approximately 64% when compared to non-stimulated cells (450 vs. 1250 nM). Addition of SOD but not inactivated SOD or catalase to PMA-activated PMNs enhanced the formation of triazole by approximately 4-fold (1950 nM). In addition, we found that the NO-releasing spermine/NO adduct (Sp/NO; 50 microM) which produces approximately 1.0 nmol NO/min generated approximately 8000 nM of triazole whereas the combination of Sp/NO and a superoxide generator (hypoxanthine/xanthine oxidase) that produces approximately 1.0 nmol O2-/min reduced triazole formation by 90% (790 nM). Addition of SOD but not catalase restored the N-nitrosating activity. We conclude that equimolar fluxes of superoxide react rapidly with NO to generate products that have only limited ability to N-nitrosate aromatic amino compounds and thus may have limited ability to promote mutagenesis via the nitrosative deamination of DNA bases.

A review of the management of a major incident involving predominantly paediatric casualties

On 27 September 1993 a double-decker bus full of secondary school children was involved in a collision with a lorry. A total of 58 people were injured, including two fatalities. All except two of the casualties were children. Forty-two casualties, including all of the seriously injured, were taken to the Accident & Emergency Department at York District Hospital. Fifteen casualties were admitted, the majority with closed head injuries. Most of the injuries were of a minor nature, predominantly soft-tissue damage and superficial lacerations. This paper reviews these injuries and the implementation of the hospital major accident (MAJAX) plan. It identifies specific problems encountered with this incident. It also describes the measures taken retrospectively to upgrade the MAJAX plan. It highlights the difficulties encountered by medical staff called to the incident who were unfamiliar with managing injuries and describes retrospective attempts to improve the awareness of trauma management skills.

Undergraduate medical student education: the case for a national curriculum

Thirty-eight teaching hospital affiliated accident and emergency departments were surveyed by post to try to find if there had been any change in undergraduate medical student teaching over the past 10 years. Twenty-six departments replied. The results showed that although there has been an improvement in the teaching of A&E medicine to undergraduates in the past few years there are still some medical schools where an A&E attachment is not mandatory. In those departments providing teaching, there is wide variation in course duration and content.

Femoral shortening in correction of congenital knee flexion deformity with popliteal webbing

Severe knee flexion deformity with popliteal webbing or pterygium is considered to be uncorrectable. The soft tissues and, in particular, the main nerves and vessels are short relative to the bone. Femoral shortening was used in correction of such a deformity in a child with arthrogryposis. The operative procedure is described. Femoral shortening should be considered as an aid to correction of any severe knee flexion deformity.

The use of histoacryl tissue adhesive for the primary closure of scalp wounds

A prospective evaluation of Histoacryl tissue adhesive for the repair of simple scalp wounds is described. Fifty wounds were repaired using the adhesive and, on examination 5 days later, 49 wounds were fully healed, the remaining wound having only a small area of dehiscence. The advantage of this method of wound repair is discussed.

Familial multiple jejunal atresia with malrotation

Two siblings with multiple jejunal atresia and malrotation of the midgut are reported. In the first, incomplete rotation of the gut was associated with two jejunal atresias and an intraluminal diaphragm. In the second, there was complete failure of rotation of the gut with two jejunal atresias, one of which had a V-shaped mesenteric defect. I am unaware of any previous reports of familial multi level small intestinal atresias with malrotation. Possible reasons for this association are discussed.

Acquisition of endemic Pseudomonas aeruginosa on an intensive therapy unit

During a 9-month period, patients, staff and environment were monitored in order to trace the source of endemic Pseudomonas aeruginosa on our intensive therapy unit (ITU). Of 81 patients studied, 14 (17%) acquired 15 different pyocin types while on the ITU. The most frequent site of colonization was the rectum (11 patients). Rectal strains subsequently appeared in urine (two patients), wound (one) and sputum (four) of six patients. Three episodes of cross-infection (wound (two), urine (one] occurred without development of rectal colonization. Strains isolated from the environment and staff were not implicated. While gastrointestinal carriage of P. aeruginosa may not be detected on admission to the ITU, excessive use of antibiotics may be responsible for apparent acquisition of the organism followed by endogenous transfer of the rectal strains to other sites of the body.

A comparison of triclosan and chlorhexidine preparations with 60 per cent isopropyl alcohol for hygienic hand disinfection

Four detergent preparations containing triclosan; two alcoholic products, containing triclosan and chlorhexidine respectively, and a detergent preparation containing chlorhexidine were compared with 60 per cent isopropyl alcohol following a single hand wash using Escherichia coli as the test organism. In vitro tests indicated that all had a high activity against hospital pathogens. The triclosan-containing preparations exhibited a significant pathogens. The triclosan-containing preparations exhibited a significant residual activity. Experiments in volunteers showed that 0.5 per cent alcoholic triclosan was significantly more effective than all other preparations tested. All the detergent preparations had an effect similar to that of 60 per cent isopropyl alcohol. None of the seven products evaluated was significantly less bactericidal than 60 per cent isopropyl alcohol.

Comparative epidemiology of gentamicin-resistant enterobacteria: persistence of carriage and infection

During a two-year period from January 1979, 260 patients have been involved in an outbreak of carriage and infection due to gentamicin-resistant enterobacteria. We have examined the duration of carriage of such enterobacteria and have compared the carriage of Klebsiella with that of other resistant enterobacteria. Carriage of gentamicin-resistant enterobacteria occurred most frequently and was least sporadic in the intestinal tract. Vaginal carriage was observed in 49 out of 68 patients tested and occurred more frequently in older patients. Oral carriage was noted in 36% of patients but was more sporadic than intestinal carriage. Rates of oral carriage were greater among moribund patients. Carriage at skin sites was related to their proximity to the perineum. Intestinal carriage of gentamicin-resistant Escherichia coli and Klebsiellae but not Klebsiella oxytoca nor Citrobacter persisted for long periods (half lives of 140 and 100 days respectively). Cessation of carriage of gentamicin-resistant Klebsiellae was due to loss of both the organism and its plasmid rather than a shedding of the plasmid. Chronic bacteriuria with gentamicin-resistant E coli and Klebsiellae (half life 180 days) but not Klebsiella oxytoca nor Citrobacter persisted for long periods.

Variation in skin and environmental survival of hospital gentamicin-resistant enterobacteria

During a period when 245 patients were infected by or harboured gentamicin-resistant enterobacteria, random sampling showed hand carriage in 33% of affected patients but in only 5% of attendant staff. Only klebsiellae were isolated from the latter. Recovery was commoner from the hands of bed-ridden patients or faecal carriers and significantly more frequent for klebsiellae (37%) and enterobacter (33%) than citrobacter (5.6%) and E. coli (5.0%). Similarly, survival on forearms of volunteers was much longer for klebsiellae and enterobacter than for citrobacter or E. coli (means respectively were 70, 45, 10 and 13 min), and on dry surfaces (means respectively were 28, 26, 3 and 7 h). Klebsiellae were isolated from 17 of the 56 dry environmental surfaces sampled. The presence of plasmid resistance determinants had no effect on survival times, either on the skin or following drying onto formica surfaces. On dry surfaces 9.5% of E. coli but only 1.3% of klebsiellae lost resistance to gentamicin. These findings accord well with recent experience in which gentamicin-resistant klebsiellae have been involved to a much greater extent than other resistant enterobacteria in hospital infection.