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O J Lehmann

Publications and source records attributed to O J Lehmann.

11 recordsLinked to original sources
PubMed1998

Acanthamoeba keratitis: multicentre survey in England 1992-6. National Acanthamoeba Keratitis Study Group.

AIM: To investigate the frequency, outcomes, and risk factors for acanthamoeba keratitis (AK) in England during the past 4 years. METHODS: An ophthalmologist in 12 of the 14 regional health authorities (RHAs) coordinated identification of patients in their region presenting with AK between 1 October 1992 and 30 September 1996. Clinical and postal patient questionnaire data were analysed. RESULTS: 243 patients (259 eyes) with an AK diagnosis were identified, equating to an annualised incidence of 0.14 per 100,000 individuals. UK resident patients for each year numbered 50, 71, 73, and 32 respectively. Among patients with sufficient data 170/237 (72%) were diagnosed early (within 30 days of presentation), 197/218 (90%) were treated with polyhexamethyl biguanide and/or chlorhexidine, and 40/243 (16%) underwent surgery. Visual acuities of 6/12 or better were achieved by 222/259 (86%) eyes, including 84 eyes of patients under review or lost to follow up. Non-contact lens (CL) wearers were associated with delayed diagnosis, increased need for surgery and a poorer visual outcome (only 10/18 eyes, 56%, achieved 6/12 acuity). 225/243 (93%) patients were CL wearers, and 205/243 (84%) were soft CL (SCL) users. Among SCL user respondents, previously identified risk factors--swimming with CL (47/138, 34%), non-sterile CL rinsing (11/138, 8%), omitted disinfection (85/138, 62%), and chlorine release disinfection (65/138, 47%)--were identified for 125/138 (91%) patients. CONCLUSIONS: Earlier diagnosis and more effective medical therapy have improved the prognosis for most AK patients. The study demonstrates the highly preventable nature of the disease: 91% of the SCL wearers could have avoided the disease by refraining from inadvisable practices, and a marked fall in frequency was seen after intensive media attention to AK, possibly in conjunction with increasing penetrance of new CL products. Since the frequency of AK appears to be largely determined by the ever changing trends in CL use, continued monitoring is indicated.

Acanthamoeba Keratitis↗
PubMed1998

Polymerase chain reaction analysis of corneal epithelial and tear samples in the diagnosis of Acanthamoeba keratitis.

PURPOSE: Acanthamoeba is an uncommon cause of corneal infection in which the best visual outcome follows prompt diagnosis and a long course of appropriate antimicrobial therapy. Because conventional detection techniques for Acanthamoeba have certain limitations, we investigated the ability of the polymerase chain reaction (PCR) to confirm the clinical diagnosis of Acanthamoeba keratitis, with the ultimate aim of achieving early diagnosis. METHODS: Using two different pairs of primers, PCR was performed on representative cultured Acanthamoeba isolates to confirm the assay's ability to amplify Acanthamoeba DNA from a wide range of acanthamoebae. Subsequently, corneal epithelial samples from 19 patients and tear samples from 12 patients with Acanthamoeba keratitis were analyzed by PCR for the presence of Acanthamoeba DNA. RESULTS: Acanthamoeba DNA was amplified by PCR from 16 (84%) of 19 corneal epithelial samples, whereas Acanthamoeba was cultured from 10 samples (53%), all of which were PCR positive. Tear samples from 8 (66%) of 12 patients were positive on PCR testing, and one tear sample was PCR positive, whereas the corresponding epithelial biopsy had yielded a negative PCR result. Samples from culture-positive patients were positive on PCR testing more frequently than those from culture-negative patients (10/10 culture-positive corneal epithelial and 5/7 [71%] culture-positive initial tear samples versus 6/9 [66%] culture-negative corneal epithelial and 2/5 [40%] culture-negative tear samples). All control epithelial (n = 15) and tear (n = 15) samples yielded negative results. CONCLUSIONS: PCR was a more sensitive diagnostic test than a culture for Acanthamoeba keratitis, and the use of two different primers achieved better sensitivity than a single set. A PCR of a tear sample also may be a useful complementary test and, in combination with PCR of epithelial samples, would prove particularly helpful in confirming the clinical diagnosis in culture-negative cases.

Acanthamoeba↗
PubMed1992

Multipoint linkage analysis of the short arm of chromosome 11 in non-insulin dependent diabetes including maturity onset diabetes of youth.

Members of three families with maturity onset diabetes of youth (MODY) and seven with "common" type 2 diabetes were typed for six DNA markers (H-RAS, INS, HBBC, PTH, CALC1, CAT) on the short arm of chromosome 11. Using conventional pairwise linkage analysis, close linkage in the MODY families was excluded for all six markers. By multipoint analysis and a genetic map of the short arm of chromosome 11, MODY was excluded from a region of at least 35 and up to 60 centiMorgans (cM) on the short arm of chromosome 11. Multipoint analysis in the type 2 families also excludes linkage to the INS, H-RAS region of at least 3 and up to 30 cM. This study using multipoint linkage analysis in non-insulin dependent diabetes provides strong evidence against a role for mutations in or around the insulin gene in the causation of MODY or type 2 diabetes in the families studied.

Chromosomes, Human, Pair 11↗
PubMed1988

Regional localization of the autosomal dominant polycystic kidney disease locus.

The localization of the autosomal dominant polycystic kidney disease locus (PKD1) within an array of anonymous polymorphic DNA sequences on chromosome 16 band p13 was determined by multipoint mapping. Nine polymorphic DNA markers, including two hypervariable sequences, were used to study 19 PKD1 and 21 reference families. PKD1 was found to lie proximal to the 3' and 5' hypervariable regions of alpha-globin and distal to the anonymous sequence CRI-0327. Somatic cell hybrid mapping places PKD1 within the region 16p13.11-16pter. The availability of an array of linked markers which bracket the PKD1 locus provides a framework for further attempts to identify the PKD1 gene and offers an improved method of presymptomatic diagnosis of the disease.

Animals↗
PubMedDate not supplied

Half-life of intracameral gentamicin after phacoemulsification.

PURPOSE: To determine the half-life of intracameral gentamicin administered during phacoemulsification. SETTING: Southampton Eye Unit, Southampton General Hospital, England. METHODS: Thirty-one patients having scleral tunnel phacoemulsification were given intracameral gentamicin in the irrigation fluid. Samples of fluid were taken from the anterior chamber at the end of the operation and at various times postoperatively. The concentration of gentamicin in the samples was determined by fluorescence polarization immunoassay and the half-life calculated for a single compartment model using a peeling algorithm. RESULTS: The concentration of gentamicin in the anterior chamber after phacoemulsification decreased by half every 51 minutes (95% confidence interval, 42 to 66 minutes). CONCLUSION: Intracameral gentamicin was cleared from the anterior chamber after phacoemulsification at a rate that prevents the maintainance of the bactericidal levels required for reliable antibiotic prophylaxis.

Anterior Chamber↗
PubMedDate not supplied

Association between nonadministration of subconjunctival cefuroxime and postoperative endophthalmitis.

PURPOSE: To determine whether not administering subconjunctival cefuroxime during cataract surgery is associated with postoperative endophthalmitis. SETTING: Southampton Eye Unit, Southampton General Hospital, England. METHODS: This retrospective, case-control study comprised nine patients who developed endophthalmitis after cataract surgery in a single ophthalmic unit over a 21 month period. Ten control patients for each case were randomly chosen from patients having cataract surgery within 1 week of the endophthalmitis case. RESULTS: None of the nine endophthalmitis patients received peroperative subconjunctival cefuroxime compared with 43 of 90 control patients (47.8%) (P = 0.008). No other variables were found to be associated with development of endophthalmitis in this study. CONCLUSION: Nonadministration of subconjunctival cefuroxime was associated with subsequent endophthalmitis. A further study to determine whether the observed association is causal is therefore warranted.

Adult↗