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D Seal

Publications and source records attributed to D Seal.

At least 19 recordsLinked to original sources
PubMed2002

Incidence and risk factors for microbial keratitis in Hong Kong: comparison with Europe and North America.

PURPOSE: To establish the incidence, etiology and risk factors for microbial keratitis (MK) in Hong Kong. METHODS: Two hundred and twenty-three new cases of presumed MK were recruited over a period of 17 months and comprehensive microbiologic studies performed. A nested case-control study was pursued for patients wearing contact lenses (CLW) to determine risk factors for MK with regards to types of CLW and hygiene practice. RESULTS: Of the 223 patients recruited, 59 (26%) wore contact lenses. Corneal scrapes yielded positive cultures from 77 patients (35% overall, 56 non-CLW, 21 CLW). Two hundred and six CLW volunteers were recruited to participate in the case-control study, of whom 135 were matched with 45 CLW patients. The annual incidence of MK was 0.63 per 10,000 population and 3.4 per 10,000 CLW with rates for daily, extended and rigid lens wear of 3.09, 9.30 and 0.44 per 10,000 CLW respectively. Pseudomonas aeruginosa was the dominant bacterial pathogen. Six cases of Acanthamoeba keratitis occurred, five in CLW (incidence 0.33 per 10,000 CLW) and one following corneal abrasion. Non-CLW developed MK at a peak age of 73, which is 10 years younger than expected for Scotland and USA. CONCLUSIONS: Previous ocular surface disease and trauma were the main risk factors for MK in Hong Kong. CLW appears at least as safe as that found in Scotland and the USA. Acanthamoeba keratitis was detected but with an incidence rate five times lower than Scotland. Factors predisposing hydrogel CLWs to MK, that were statistically significant, included overnight wear, poor hygiene and smoking.

Acanthamoeba Keratitis↗
PubMed1997

Somatosensory evoked potential monitoring during cardiac surgery: an examination of brachial plexus dysfunction.

OBJECTIVE: To observe the effects of the Favoloro and sternal retractors on the ulnar and median nerve somatosensory evoked potentials (SSEPs) and to identify any relationship with postoperative brachial plexus injury. DESIGN: Prospective study. SETTING: University hospital. PARTICIPANTS: Twenty cardiac patients. INTERVENTIONS: SSEPs were studied in patients undergoing cardiac surgery using normothermic cardiopulmonary bypass. Evoked potentials were obtained from bilateral median and ulnar nerves. MEASUREMENTS: The incidence of nerve-specific SSEP changes and their temporal relationship to retractor usage were determined. The overall incidence of SSEP changes was 75%. There were no differences (p > 0.05) between the group showing changes (n = 15) and the group with no changes (n = 5) with respect to age, body surface area, weight, cross-clamp or cardiopulmonary bypass times. There also were no differences (p > 0.05) between the frequencies of left- and right-sided changes, or in nerve-specific SSEP changes. Seventy-four percent of SSEP changes correlated with retractor usage. No SSEP changes were associated with the Favoloro retractor. Significant SSEP depression, assessed by either percentage reduction in amplitude or persistent amplitude reduction, occurred in the absence of postoperative neurological deficits. There were no detected postoperative brachial plexus injuries. CONCLUSIONS: SSEP changes correlate with the use of the sternal retractor but not the Favoloro retractor. It was not possible to replicate the results of previous investigators in predicting postoperative neurological deficits based on the SSEP changes, and therefore the routine application of SSEP as a monitor cannot be recommended on the basis on these data.

Aged↗
PubMed1996

Successful medical therapy of Acanthamoeba keratitis with topical chlorhexidine and propamidine.

INTRODUCTION: Following laboratory studies on new potential chemotherapy for Acanthamoeba keratitis, when chlorhexidine and propamidine provided an additive in vitro effect, a series of 12 patients with culture-proven Acanthamoeba keratitis from three UK centres was monitored during and after therapy. METHODS: In all cases the clinical diagnosis was confirmed by amoebal culture. In some instances identification of the protozoa by direct microscopy of corneal tissue was possible. The medication was provided topically in drop form until the keratitis had resolved. In vitro sensitivity to chlorhexidine and propamidine was performed on all isolates and compared with sensitivity to a range of other drugs used for treatment of the infection. RESULTS: In vitro drug testing confirmed that trophozoites and cysts of all 12 Acanthamoeba isolates were fully sensitive to chlorhexidine and propamidine. Therapy was satisfactory for controlling and eradicating the acanthamoebal infection in all patients. Three patients developed discrete stromal infiltration at the site of infection that resolved 1 week after commencing therapy, with or without use of steroids. Two patients developed a late inflammatory effect in the stromal scar at 6 months, which resolved with steroids. No clinical evidence of chlorhexidine toxicity was found in any patients. CONCLUSIONS: The combination of topical chlorhexidine and propamidine was very effective for treating Acanthamoeba keratitis provided the drugs were continued for a sufficient period. No drug toxicity or resistance of Acanthamoeba isolates was observed in the 12 treated patients.

Acanthamoeba↗
PubMed1992

Possible environmental sources of Acanthamoeba spp in contact lens wearers.

The water supply and dust samples from the home environment (bathrooms and kitchens) of 50 wearers of contact lenses (CLs) were cultured for the presence of free-living amoebae. CL cases, solutions, and water taps were cultured for bacteria, which amoebae require for growth. Acanthamoeba spp were isolated from water drawn from six bathroom cold water taps (tank supplied), five in the presence of limescale, and from one kitchen cold water tap (mains supplied). There was an association between the presence of limescale in water and direct culture for free-living amoebae, suggesting that scale provides a favourable microenvironment for amoebae. Acanthamoebae were also found in dust from around one washbasin. Nineteen of 50 CL cases, 12/122 CL care rinsing solutions, and 59/100 cold water taps yielded Gram negative bacteria which could be ingested by amoebae. It is concluded from this study that CLs should not be washed in first-drawn tank-fed cold water, especially if limescale is present, and that soft CLs should be rinsed in manufactured single-use, sterile solutions. Rigid CL and CL cases should only be washed with boiled tap water (preferably hot), or single-use sterile solutions, and stored dry to prevent multiplication of amoebae and Gram negative bacteria.

Acanthamoeba↗
PubMed1991

Role of cell-mediated immunity to staphylococci in blepharitis.

We studied cell-mediated immunity to staphylococcal antigens in 116 patients with chronic blepharitis and eight normal subjects. Antibodies in tears and blood were measured. Enhanced cell-mediated immunity to Staphylococcus aureus was demonstrated in 46 of 116 patients (40%) in the absence of antibodies to teichoic acid but not among normal subjects. Symptoms of grittiness and morning stickiness were more frequent among patients without enhanced responses. Folliculitis occurred more commonly among patients with enhanced immunity. Marginal keratitis occurred equally among patients with and without enhanced systemic immunity, but patients with enhanced response more commonly required topical corticosteroid therapy. Desensitization to staphylococcal antigens could be investigated as a potential therapeutic approach in selected patients.

Adult↗
PubMed1991

Northwick Park Infection Consultation Service. Part I. The aims and operation of the service and the general distribution of infection identified by the service between September 1987 and July 1990 [see comment].

The Northwick Park Infection Consultation Service (ICS) is a collaborative service operated by the departments of Medical Microbiology and Infectious Diseases where personnel and skills are combined. Its aim is to improve the availability and effectiveness of consultation for infection-related problems. This paper sets out the framework for establishing an ICS and also details the general distribution of infection identified by the Northwick Park ICS in a study carried out between September 1987 and July 1990. Part II assesses the contribution that the ICS made to the management of infection. One thousand and thirty-eight (1038) patients were seen on the ICS. Seventy-five per cent (776) were judged to be infected and in 691 this was a probable or certain diagnosis. Skin and subcutaneous tissue, respiratory tract, and genito-urinary tract infections accounted for 64% of the total. Eighty-seven per cent of infections required treatment with intravenous antibiotics, 22% were associated with concomitant bacteraemia, and 2.7% of patients died as a direct result of their infection. Sixty-four per cent of consultations were unsolicited and arose from laboratory results or the clinical information on the form accompanying the specimen: over one quarter were initiated before results were available. These infections were no different in either severity or nature from those identified by solicited requests to either department. Fifty-three per cent of consultations had a moderate to high clinical component. The results emphasise the importance of infection in hospitals and highlight the advantages of a collaborative approach from the departments of Medical Microbiology and Infectious Diseases.

Cross Infection↗
PubMed1991

Northwick Park Infection Consultation Service. Part II. Contribution of the service to patient management: an analysis of results between September 1987 and July 1990.

The establishment of Infectious Disease teams combining microbiological and clinical expertise has recently been recommended by a joint working part of the Royal College of Physicians and the Royal College of Pathologists. The Northwick Park Infection Consultation Service (ICS) has been operating on these lines since 1983; details are given in Part I. Part II assesses the contribution that the ICS has made to the management of infection in a study of 1038 patients undertaken between September 1987 and July 1990. The areas of patient diagnosis, treatment, investigation and isolation were examined to assess the appropriateness of the attending doctor's management of infection and the benefits resulting from recommendations made by the ICS. At the time of consultation the correct diagnosis had already been made or considered in 93% of patients, essential investigations needed to confirm or refute the diagnosis performed in 92%, and side-room isolation correctly instituted in 81% of patients requiring it. However, 41% of 776 infected patients were receiving suboptimal treatment: this was significantly more frequent in unsolicited consultations (P less than 0.05). Advice was given following consultation in 893 of 1038 patients (86%) and related to treatment (66%), investigation (41%), diagnosis (30%) and patient isolation (4%). Of 844 patients where receipt of advice could be accurately assessed, it was taken fully in 708 (84%), partly in III (13%), and went unheeded in 25 (3%). Advice on diagnosis or investigation enabled the correct diagnosis to be reached in 30% of consultations and in a further 47 patients (5%), the diagnosis was proposed by the ICS on initial consultation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Microbial keratitis--the false negative.

The investigation of presumed microbial keratitis includes microscopy and culture of corneal specimens obtained by scraping the infiltrated cornea. Routine microscopy fails to identify the infecting organism in about 15% of cases. We discuss the problems presented by 20 such eyes which required further investigation. We present a diagnostic algorithm aimed at reducing the delay in identifying the pathogen and increasing the rate of positive culture. This is important since unusual pathogens may require treatment with drugs other than the 'first line' broad spectrum combination of an aminoglycoside and a cephalosporin. The algorithm allows sequential restaining and reculturing of specimens for more thorough investigation. In addition to the use of special stains and culture conditions, it presents indications for further corneal scrapes and biopsies. Uncontrolled infection resulted in five perforations and penetrating keratoplasty was indicated in 11 cases. The visual outcome for these patients was poor with fewer than 30% achieving 6/12 acuity. The delay in diagnosis increases morbidity and this should be significantly reduced by adopting the algorithm we propose.

Adult↗
PubMed1991

In vitro studies of water activity and bacterial growth inhibition of sucrose-polyethylene glycol 400-hydrogen peroxide and xylose-polyethylene glycol 400-hydrogen peroxide pastes used to treat infected wounds.

Water activity and bacterial growth inhibition have been studied in formulations comprising either sucrose or xylose along with polyethylene glycol 400 and hydrogen peroxide. The pastes are chemically stable for 6 months if stored at 2 to 8 degrees C and have been shown to lower water activity to levels below those essential for bacterial growth and to be bactericidal even when diluted up to 50% with serum. Of the organisms tested, Staphylococcus aureus proved the least susceptible to the bactericidal effects of these pastes, and candida and gram-negative organisms proved the most susceptible. Pastes without hydrogen peroxide were less rapidly bactericidal than pastes with hydrogen peroxide, while polyethylene glycol 400 itself was found to have considerable antimicrobial activity. It is suggested that sucrose paste may be of benefit as a treatment for infected and malodorous wounds.

Animals↗
PubMed1991

Combined prophylactic effect of ultraclean air and cefuroxime for reducing infection in prosthetic surgery.

One hundred seventy-four elective operations for hip and knee prostheses were undertaken in conditions of ultra-clean air and antibiotic prophylaxis (with cefuroxime), as the recent Medical Research Council multicenter study suggested that this combination was most likely to give the lowest infection rate. No acute infections of a prosthesis occurred (early infection rate less than 0.6%), while the rate was 2.9% for purulent wound infection which did not involve the prostheses. Late infections, at 3 months and 1 year, occurred in only 2 patients (a rate of 1.1%), resulting from probable bacteremia, which necessitated removal of the prosthesis. These results are considered satisfactory, especially in a compromised patient population of mean age 71 years. Such low infection rates underscore the need to continue the combined use of ultraclean air and antibiotics for hip and knee prosthetic surgery, or to introduce them where absent, to prevent the occurrence of airborne staphylococcal infection; either technique alone was shown to be less effective in the Medical Research Council multicenter study.

Aged↗
PubMed1990

Role of staphylococcal toxin production in blepharitis.

Lid isolates of Staphylococcus aureus and coagulase-negative staphylococci (CNS) from controls (12 S. aureus and 110 CNS) and from patients with blepharitis (17 S. aureus and 171 CNS) were tested for production of alpha, beta, delta, epsilon, and previously undescribed hemolytic toxins, because toxin production has been implicated as a cause of blepharoconjunctivitis. The electrolyte content of agar media required for toxin production was first investigated. Alpha-lysin was found to be produced by all isolates of S. aureus colonizing lids of normal controls and patients with blepharitis, but by none of 281 CNS isolates. A new toxin was identified, having low molecular weight (5 kd), produced by one CNS strain isolated from a blepharitic lid. It was produced on basic nutrient agar that lacked sodium but contained glucose, which inhibited production of alpha-lysin. It hemolyzed rabbit and sheep erythrocytes and, surprisingly, was neutralized by polyclonal antiserum to alpha-lysin. This may explain occasional reports of alpha-lysin production by CNS. The overall results do not support a hypothesis of hemolytic toxin production by staphylococci as a general cause of blepharitis.

Bacterial Toxins↗
PubMed1990

Encephalitis due to Epstein-Barr virus.

Acute encephalitis due to Epstein-Barr virus is described. The initial diagnosis was based on clinical features and a positive Monospot test. Early treatment with intravenous acyclovir was given; steroids were not used. The patient made a rapid and complete recovery from a comatose state. The effectiveness of acyclovir in this condition remains unproven but early treatment is recommended in severely ill patients whose prognosis is uncertain.

Acyclovir↗
PubMed1990

Acanthamoeba keratitis--resistance to medical therapy.

Successful medical therapy of Acanthamoeba keratitis has been reported with combination therapy; topical Brolene and neomycin. Resistance has not so far been identified as a problem, but was the basis for recurrent disease observed in a patient with bilateral infection. Eradication of amoebae was finally achieved following prolonged topical therapy and two corneal grafts in each eye. Topical anti-amoebic therapy with paromomycin, benzethonium chloride, clotrimazole and R11/29 (a phenanthridinium compound), was continued for three months post-operatively. No further recurrences occurred during 14 months' follow-up. Drug sensitivities were performed for three isolates of Acanthamoeba sp (group II) which demonstrated the development of resistance to Brolene and arsenic. In addition, the resistant isolates were temperature-sensitive mutants which would not grow at temperatures above 30 degrees C. This could explain 'culture-negative' results in some cases of clinical recurrence when incubation of laboratory samples had only been performed at 37 degrees C.

Acanthamoeba Keratitis↗