Eye banking in Europe 1991-1995.
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Cornea↗
Biomedical subjects
A B Tullo
Publications and source records attributed to A B Tullo.
Polymerase chain reaction for detection of Chlamydia trachomatis in conjunctival swabs.
AIMS/BACKGROUND: Ocular Chlamydia trachomatis infection in the west occurs as opthalmia neonatorum, acquired from the mother, or adult paratrachoma which is also associated with current genital tract infection. Accurate rapid laboratory diagnosis facilitates management, but the relative merits of antigen detection or DNA amplification tests are unresolved. METHODS: A polymerase chain reaction (PCR) test was developed which amplified part of the plasmid shared by all the serovars of C trachomatis. Conjunctival swabs were tested using an in house immune dot-blot test (IDBT) for chlamydial lipopolysaccharide antigen, a commercial direct fluorescent antibody (DFA) test for chlamydial elementary bodies, and the PCR (DNA extracted using guanidinium lysis buffer). RESULTS: The PCR achieved a detection limit of 100 plasmid copies (10 elementary bodies). In a combined retrospective and prospective clinical evaluation, the PCR and IDBT gave identical results with 21 positive and 57 negative eye swabs. However, interpretation of the DFA test required meticulous examination of the stained smear, sometimes by two microscopists. CONCLUSIONS: The PCR is likely to play an increasing role in the diagnosis of ocular C trachomatis infection because of its excellent sensitivity and specificity.
Adult↗
Tenascin-C expression in normal, inflamed, and scarred human corneas.
AIMS/BACKGROUND: In adult tissues the expression of tenascin-cytotactin (TN-C), an extracellular matrix glycoprotein, is limited to tumours and regions of continuous renewal. It is also transiently expressed in cutaneous and corneal wound healing. There are limited data regarding its expression in inflammation and scarring of the adult human cornea. In this study, TN-C expression patterns in normal, inflamed, and scarred human corneas have been examined. METHODS: Penetrating keratoplasty specimens were selected from cases of herpes simplex keratitis, herpes zoster ophthalmicus, rheumatoid arthritis ulceration, bacterial keratitis, rosacea keratitis, interstitial keratitis, and previous surgery so as to encompass varying degrees of active and chronic inflammation and scarring. TN-C in these and in normal corneas was immunodetected using TN2, a monoclonal antibody to human TN-C. RESULTS: There was no TN2 immunopositivity in normal corneas except at the corneoscleral interface. In pathological corneas, TN2 immunopositivity was localised in and around regions of active inflammation, fibrosis, and neovascularisation. TN2 positivity was less in acute inflammation than in active chronic inflammation. Mature, avascular scar tissue and epithelial downgrowth were TN2 negative. CONCLUSION: These results indicate that in the adult human cornea, TN-C expression is induced in regions of inflammation, fibrosis, and neovascularisation, but that expression is absent in mature, avascular scar tissue. This suggests a role for this glycoprotein in inflammation, healing, and extracellular matrix reorganisation of the cornea.
Adolescent↗
Comparison of primer sets for detection of fecal and ocular adenovirus infection using the polymerase chain reaction.
Adenoviruses of subgenus F (types 40 and 41) cause infantile gastroenteritis and adenoviruses principally of types 1-7 are found in feces during respiratory or generalized infections. Adenoviruses (mostly types 3, 4, 8, 19, or 37) are also linked with follicular or epidemic conjunctivitis. The diagnostic efficiency of the polymerase chain reaction (PCR) for adenoviruses was assessed using genus-reactive primers H1 and H2 or JCH1 and JCH2 or subgenus F-specific primers F1a and F2a. With diarrheal stool specimens containing subgenus F adenoviruses, F1a/F2a PCR achieved at least as high a positivity rate (75/76 [99%]) as electron microscopy (72/76 [95%]) and was more sensitive than polyclonal antibody-based immune electron microscopy (IEM) for subgenus identification (75/76 [99%] vs. 66/76 [87%], P = 0.008). Twenty-three subgenus F strains untypeable by monoclonal antibody-based IEM were typed as 40 (n = 4) or 41 (n = 19) by Hha I digestion of the PCR product. The genus-reactive primer pairs provided DNA amplification assays of generally equal efficiency on conjunctival swab specimens though possible nucleic acid degradation in DNA extracts during storage could have meant that JCH1/JCH2 PCR was truly the more sensitive. The use of either genus-reactive primer set on fecal specimens cannot be recommended because, although the positivity rates with subgenus F PCR positive specimens were high (70/75 [93%] for H1 and H2, 14/15 [93%] for JCH1 and JCH2), the detection rates were disappointing with similar specimens yielding nonsubgenus F adenoviruses.
Adenoviridae Infections↗
Multiplex polymerase chain reaction for adenovirus and herpes simplex virus in eye swabs.
Adenoviruses and herpes simplex virus (HSV) can cause clinically indistinguishable episodes of acute eye disease. Adenovirus infection is associated with nosocomial outbreaks and HSV may result in episodes of recurrent ocular inflammation. In a comparison of multiplex PCR for the two viral DNAs and virus isolation in cell culture, identical results were obtained for 18 of 20 specimens (positive for adenovirus in 5, HSV in 5, and negative in 8). One specimen was falsely negative for each viral DNA. Inclusion of human beta-globin primers in the adenovirus-HSV reaction was precluded by a consequential 10--100-fold reduction in sensitivity for the two viral targets and by the failure of beta-globin DNA amplification at the annealing temperature (45 degrees C) required to ensure detection of adenoviruses of serotypes 7 and 11 with the selected adenovirus primers. A single-target beta-globin PCR gave positive results with 19 of the 20 specimens prepared by treatment with proteinase K lysis buffer, indicating the effectiveness of this simple DNA extraction procedure. Nonetheless, the availability of effective antiviral therapy for HSV made monitoring for extraction failure using human primers crucial to avoid false-negative results for HSV DNA. Adenovirus-HSV PCR has considerable potential for the rapid diagnosis of viral eye disease particularly if beta-globin primers can be included in the reaction.
Adenovirus Infections, Human↗
Investigation of microbial keratitis: an audit from 1988-1992.
An audit was performed of the investigation of 263 cases of microbial keratitis severe enough to be admitted to the Manchester Royal Eye Hospital over the 5-year period, 1988-1992. A pathogen isolation rate of 37% was noted during the first year which increased to 79% (p < 0.05) by the final year of audit. In late 1991 a new method of inoculating enrichment broths was introduced, which also contributed by increasing the yield from corneal scrapes. The audit process resulted in the development of and adherence to our investigation protocol, improved communication between Manchester Royal Eye Hospital and the microbiology laboratory, the implementation of a new investigatory method, and a significantly improved microbial isolation rate.
Adolescent↗
Diurnal variations in human corneal thickness.
AIM: To elucidate the diurnal variation in human corneal thickness over a 48 hour period. METHOD: Changes in central corneal thickness were monitored in eight healthy subjects (four male, four female) aged between 10 and 63 years using an ultrasonic pachymeter. Measurements were made over a 48 hour period-immediately before sleep, immediately upon waking and at 15, 30, 45 minutes, 1, 1.5, 2, 2.5, 3 hours, and at 2 hour intervals thereafter throughout the remainder of each day. RESULTS: The mean corneal thickness for the group (SD) was 546 (14) microns, with a mean overnight increase of 5.5% (2.9%) (range 1.9-12.6%) and a maximum diurnal increase of 7.2% (2.8%) (range 2.1-14.3%). Individual differences in the extent of diurnal and overnight variation occurred within the group. For three subjects, the first reading taken on waking was not the highest and corneal thickness continued to increase. CONCLUSION: These data confirm an increase of corneal thickness during sleep, but also reveal considerable variation during waking hours. Thus, the overnight changes in corneal thickness are not truly representative of diurnal variations in human corneal thickness and, in fact, much greater diurnal variation occurs than the 3.0-4.4% previously reported.
Adolescent↗
Detection of herpes simplex virus DNA in donor cornea culture medium by polymerase chain reaction.
AIMS/BACKGROUND: Herpes simplex virus (HSV) may establish latent infection in the cornea and therefore be transmissible by corneal transplantation. Monitoring of donor cornea culture medium was evaluated for HSV infection. METHODS: HSV was sought using virus isolation in cell culture, and its DNA was amplified to detectable levels using the polymerase chain reaction (PCR). RESULTS: Virus isolation in cell culture was negative on neat, cell pellet, and cell free supernatant prepared from the spent culture media of 80 corneas. Three cell pellets (3.8%) were positive for HSV DNA. The PCR positive culture negative results might have reflected latent rather than active HSV infection of the cornea. Post transplant follow up of the three recipients of corneas with HSV PCR positive organ culture media revealed no evidence of HSV induced eye disease or primary graft failure. CONCLUSION: Screening of corneal culture medium for HSV by virus culture or for HSV DNA by PCR could not be recommended.
Aged↗
Is it time to stop using chloramphenicol on the eye? Safe in patients with no history of blood dyscrasia.
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Chloramphenicol↗
Corneal transplantation in Britain.
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Corneal Transplantation↗
Polymerase chain reaction for rapid detection of ocular adenovirus infection.
Adenoviruses are associated with endemic and epidemic acute conjunctivitis, large nosocomial outbreaks reflecting virus transmission on unwashed hands or inadequately sterilised ophthalmic instruments. The polymerase chain reaction (PCR) proved more sensitive than antigen detection by immune dot-blot test for the rapid diagnosis of ocular adenovirus infection (sensitivities in a retrospective study 112/123 (91%) versus 72/123 (59%), P < 0.001). Indeed, in a prospective comparison, DNA amplification and virus isolation generated similar numbers of positive results (34 versus 32), though five PCR positive results were possibly false positives. The sensitivity of the PCR was largely independent of adenovirus subgenus or serotype, though reduced sensitivity with subgenus B strains could not be excluded. Specimen preparation for DNA amplification using a simple lysis buffer proved more effective than phenol-chloroform extraction. The immune dot-blot test gave unavoidable false positive results, but with the PCR this problem could be minimized by technical modifications. The PCR could replace antigen detection and virus isolation as the initial test for adenoviruses in conjunctival swabs, with cell culture only being retained for adenovirus serotyping in PCR positive specimens and for other viruses such as herpes simplex.
Adenoviridae↗
Infrared thermography of the tear film in dry eye.
Infrared ocular thermograms were recorded for a group of 36 dry eye patients and for 27 age- and sex-matched controls. Mean ocular surface temperature was greater in the dry eye group (32.38 +/- 0.69 degrees C) compared with the control group (31.94 +/- 0.54 degrees C; p < 0.01). In addition, there was a greater variation of temperatures across the ocular surface in the dry eye group, illustrated by the difference in temperature between the limbus and the centre of the cornea (0.64 +/- 0.20 degrees C in dry eye patients compared with 0.41 +/- 0.20 degrees C in the control group; p < 0.001). This parameter was also shown to be greater in dry eye patients who displayed either a fast tear break-up time or a poor Schirmer's test result. Infrared thermography is a non-invasive and objective technique that may prove a useful research tool for study of the tear film, its deficiencies and its various treatment modalities.
Adult↗
Prospective study of adenovirus antigen detection in eye swabs by radioimmune dot-blot.
Rapid laboratory diagnosis of ocular adenovirus infection is crucial in the containment of nosocomial transmission of the virus. In a large prospective study of adenovirus assay in eye swabs, antigen detection by radioimmune dot-blot (turnaround time 72 hours) achieved a sensitivity of 67% (239/355) and a specificity of 93% (3065/3285) in comparison with virus culture (median turnaround time 14 days). When specimens weakly reactive for adenovirus antigen, or equally reactive for both adenovirus antigen and Chlamydia trachomatis antigen, were considered falsely reactive in the adenovirus test, the sensitivity of the latter was reduced and false positive reactions were only marginally less frequent. The radioimmune dot-blot provides a more rapid diagnosis of ocular adenovirus infection than virus culture, but the high risk of false negative and in particular false positive results limits its clinical utility.
Adenovirus Infections, Human↗
Penetrating keratoplasty for pseudophakic corneal oedema.
AIMS: The study was designed to investigate the results of penetrating keratoplasty (PK) for pseudophakic corneal oedema (PCO). METHODS: Retrospective analysis of 80 consecutive patients (82 eyes) who underwent PK for PCO between the years 1980-1992 with a minimum follow up of 12 months. RESULTS: PKs for PCO have accounted for as many as 20% of all grafts performed in the hospital in recent years. The interval between cataract extraction and PK ranged from 6 to 161 months (mean 51 months). The intraocular lens was removed in 45 (55%), left in situ in 30 (37%), and exchanged in seven (8%) of cases respectively. Of the intraocular lenses involved 62% were iris supported, 31% angle supported, and 7% were posterior chamber lenses. Actuarial analysis shows graft survival to be 91% at 1 year and 86% at 2 years after surgery. The likelihood of graft survival was significantly enhanced by removal of the intraocular lens (p < 0.01). A corrected Snellen visual acuity worse than 6/60 was present in 36% of patients with a clear corneal graft. Ocular comfort was achieved in all patients with a clear corneal graft. CONCLUSION: PK for PCO resulted in a disappointing visual result in a large proportion of patients. PK was, however, successful in relieving pain and corneal ulceration when present.
Corneal Edema↗
Florid xanthelasmata (yellow lids) in orbital Wegener's granulomatosis.
AIMS: A new sign of florid xanthelasmata is described in four male patients with orbital manifestations of Wegener's granulomatosis. METHODS: The case notes of four patients with Wegener's granulomatosis, with orbital involvement accompanied by yellow lid lesions, are reviewed. RESULTS: All the patients had active Wegener's granulomatosis at the time the lid lesions were most florid. The lesions gradually resolved as the inflammatory disease was controlled with immunosuppressive agents. The lesions displayed marked asymmetry and predominantly involved the side with the most severe inflammation. Abnormalities of lipid metabolism were not identified and it is believed that the lesions developed in a susceptible anatomical region affected by a vasculitic process. CONCLUSION: A 'yellow lid' associated with orbital inflammation and is a strong pointer to the clinical diagnosis of Wegener's granulomatosis.
Adult↗
Ophthalmic molluscum contagiosum: clinical and immunopathological features.
AIMS: A study of ophthalmic molluscum contagiosum infection was undertaken to define its clinical presentation and immunopathological features. METHODS: Retrospective analysis of 35 cases of histologically proved molluscum contagiosum infection was carried out. Diagnosis was delayed in 40% of cases resulting in repeated clinic visits. RESULTS: Twenty one patients were noted to have ocular surface changes; two patients were immunocompromised. All cases were eventually treated by excision of the lesion (19 had cautery to the lesion base) and there was recurrence in two cases. Immunohistochemical analysis of biopsy specimens showed that T lymphocytes were a consistent finding in adjacent dermis and epidermis although they did not infiltrate the molluscum lesions. Smaller numbers of macrophages were also demonstrated. There was a notable cross reactivity by a T cell antibody to the molluscum bodies. CONCLUSION: The study shows the varied presentation of molluscum contagiosum infection to the ophthalmologist and the nature of the local immune response to the virus.
Adolescent↗
Waiting times and the patient's charter.
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Outpatient Clinics, Hospital↗
Comparison of topical and oral acyclovir in early herpes zoster ophthalmicus.
Poor systemic absorption has limited the efficacy of early oral acyclovir in herpes zoster ophthalmicus (HZO). Aqueous humour levels are substantially higher if the drug is administered topically to the eye. A multicentre open randomised study was performed to compare the ocular prophylactic effects of topical and oral acyclovir. Fifty-seven patients with HZO within 72 hours of the onset of rash received either topical acyclovir ointment or 800 mg oral acyclovir, both 5 times daily for 7 days, and were followed for 12 months. Patients receiving ointment were significantly more likely to have ocular complications (p < 0.02) and anterior uveitis was significantly more frequent (p < 0.01) and severe (p < 0.01). Corneal hypoaesthesia was significantly more frequently (p < 0.05) and severe (p < 0.02) at 1 month. From 2 weeks patients receiving ointment were more likely to have pain and at all times their pain was more severe, but these differences were not statistically significant. In spite of its apparently better penetration topical acyclovir appears to have no prophylactic value in the management of early HZO.
Acyclovir↗