Selection of gentamicin-resistant variants of Pseudomonas aeruginosa in the rat cornea.

Pseudomonas aeruginosa often persists in ocular infections despite intensive antimicrobial therapy. In this study, gentamicin-resistant small colony variants (SCV) were selected in vitro from three gentamicin-susceptible Pseudomonas isolates by incubation with antibiotic. In the rat cornea, SCV were selected from two of these strains by administration of gentamicin either topically or intravenously.

Leukocytes in the graft bed associated with corneal graft failure. Analysis by immunohistology and actuarial graft survival.

Immunohistochemical staining analysis using monoclonal antibodies was performed on 107 recipient corneas removed at graft. There were significantly more infiltrating cells bearing one or more of the leukocyte-common antigen, class II major histocompatibility complex antigens, various myeloid-lineage markers, and a peripheral T cell marker, in the graft beds of those recipients who subsequently lost a corneal graft than there were in the graft beds of those for whom the outcome was successful. The hypothesis that large numbers of leukocytes in the recipient graft bed would be correlated with subsequent graft failure was examined by actuarial graft survival analysis.

Duodenal obstruction by abdominal aortic aneurysms.

We report a case of duodenal obstruction caused by an abdominal aortic aneurysm. The duodenum was firmly attached to the lateral wall of the aneurysm by a tough, fibrous band. Duodenal obstruction is a rare presenting complaint in a patient with an abdominal aortic aneurysm.

Effectiveness of a decontamination method for donor corneas.

A retrospective study was made of the effectiveness of an eye bank decontamination and storage method. A comparison was made between microbial cultures taken from the limbus at enucleation and from scleral remnants recovered after surgery. Organisms were isolated from the limbus of 73% of donor eyes and from 4% of remnants.

Assessment of the Dutch organ-culture system of corneal preservation within the Eye Bank of South Australia.

Thirteen per cent of all corneas harvested by the Eye Bank of South Australia during 1986 were discarded because storage time in McCarey-Kaufman medium exceeded four days. We have therefore examined the suitability of the Dutch method of long-term corneal storage for our purposes. Twenty-two human corneas that had been discarded from the Eye Bank were assessed using the trypan blue-sucrose staining technique, and then placed into long-term storage for 15 to 17 days.

First report of the Australian Corneal Graft Registry.

In the Australian Corneal Graft Registry's first 18 months of operation, May 1985 to November 1986, data supplied by 53 surgeons relating to 322 graft recipients have been entered and analysed with respect to: the most common presenting diseases (primarily keratoconus, bullous keratopathy and corneal opacities), risk factors (especially prior sensitisation to HLA antigens, corneal vascularisation, past or present anterior segment inflammation and history of raised intraocular pressure [IOP]), donor and recipient sex, cause of donor death, storage procedures for donor eyes, operative procedures accompanying the grafts themselves, and preliminary indications of overall graft survival by actuarial analysis. It is hoped that the establishment of this Registry will not only reinforce the use of actuarial graft survival analysis as the method of choice for transplantation surgeons wishing to monitor the survival of their patients and grafts, but will also provide a useful service for the Australian ophthalmic community in general.

Acanthamoebic keratitis diagnosed by paracentesis and biopsy and treated with propamidine.

A previously healthy 53-year-old man had keratitis of the right eye for six months, unresponsive to topical medical therapy. Acanthamoeba was grown from tissue obtained by corneal biopsy and from aqueous from an anterior chamber tap. The patient was treated with propamidine isethionate 0.

Uveitis: a strategy for diagnosis.

Uveitis may be the first presentation of a wide variety of underlying ocular and systemic diseases. It is important for the ophthalmologist to make a specific diagnosis in order to instigate specific therapy and give an accurate prognosis. The ability to recognise the clinical patterns of uveitis and to initiate appropriate investigations should form the basis of the ophthalmologist's management of the condition.

Topical steroid, cyclosporin A, and the outcome of rat corneal allografts.

The effects of a combination of topical corticosteroid and cyclosporin A on corneal graft survival were tested in a model of penetrating keratoplasty in the inbred rat. Topical medications were applied four times daily to the graft for 28 days postgraft. Neither topical steroid (1% prednisolone acetate) nor topical cyclosporin (1% in chremophor EL/ethanol) was able to modify the overall incidence of rejection, though all steroid-containing medications delayed the onset of rejection significantly.

Endophthalmitis following cataract extraction.

We describe a case of bacterial endophthalmitis complicating routine cataract extraction and intraocular lens implantation in a 91-year-old woman. The ocular and systemic factors that may have predisposed to intraocular infection in this case, and the possibility of predicting these pre-operatively, are discussed.

Host, microbial, and pharmacological factors affecting the outcome of suppurative keratitis.

A review of 87 cases of microbial keratitis in South Australia was made to determine the factors which influence the outcome of the disease. The preceding pathology and the extent of ulceration at presentation were found to be significant, while the presence of hypopyon was less important. Infection with Pseudomonas aeruginosa was most likely to result in a poor outcome.

The role of resident accessory cells in corneal allograft rejection in the rabbit.

Corneal grafts are more likely to be rejected when placed in a vascularized rather than in a normal host cornea. Using immunohistochemical techniques, normal rabbit cornea was found to contain measurable numbers of cells of hemopoietic origin, probably of either macrophage or dendritic lineage. After the deliberate induction of corneal inflammation and neovascularization, the number of these accessory cells was found to increase significantly.

Endothelial repair in the rat cornea.

Destruction of the central endothelium of the rat cornea was produced by mechanical injury, total debridement, or transcorneal freezing. Endothelial repair was then studied using specular microscopy, histological staining, pachymetry, and autoradiographic analysis of the incorporation of tritiated thymidine into nuclear DNA. Following an initial process of cell slide to cover the endothelial defect, extensive cellular division occurred at the margins of the wound, with approximately 45% of cells in the wound area showing incorporation of tritiated thymidine.

Effect of inflammation on antibiotic penetration into the anterior segment of the rat eye.

Bacterial infections were established in the right cornea of rats. Animals infected with Staphylococcus aureus were given cephradine intravenously (IV) (40 mg/kg) or topically (50 mg/ml) to both eyes. Animals infected with Pseudomonas aeruginosa were given gentamicin sulfate IV (40 mg/kg) or topically (10 mg/ml).

Acanthamoebic keratitis in a healthy Australian man.

We report a case of acanthamoebic keratitis that occurred after minor ocular trauma in a healthy 31-year-old man. Multiple microbiological investigations failed to reveal the causative organism, which was identified as Acanthamoeba castellanii only after a corneal graft operation had been performed. A review of previously described cases reveals that this rare ocular infection tends to cause recalcitrant corneal ulcers after minor eye injuries in otherwise healthy individuals.

Fuchs's heterochromic cyclitis and posterior capsulotomy.

We report a case of intractable glaucoma following an uncomplicated secondary posterior capsulotomy in a 48-year-old male with Fuchs's heterochromic cyclitis. The patient had been free of inflammation and glaucoma since cataract extraction 27 years previously. We also report the results of phenotypic analysis of lymphocytes removed from the anterior chamber.

A microprocessor-driven one-operator forced-choice preferential looking apparatus.

Forced-choice preferential looking (FPL) is a behavioural technique for the estimation of visual acuity in preverbal children. We have constructed an electromechanical FPL apparatus controlled by a microprocessor requiring just one operator. Sixty-three babies aged between six weeks and eleven months were evaluated with an overall success rate of 83% in obtaining an acuity measurement.

A rat model of bacterial keratitis. Effect of antibiotics and corticosteroid.

A model of bacterial keratitis in rats was developed to quantify the effect of antibiotics and corticosteroid on the infective process. Corneas were inoculated with Staphylococcus aureus, Pseudomonas aeruginosa, or Streptococcus pneumoniae. The natural history of infection with these organisms was determined.

A comparison of the effects of topical cyclosporine and topical steroid on rabbit corneal allograft rejection.

A comparison was made of the effects of topically applied cyclosporine, and topically applied prednisolone acetate, on the prolongation of corneal allograft survival in a recently developed prevascularized rabbit eye model. Animals were treated four times daily for 28 days postgrafting. Both drugs prolonged graft survival when compared with placebo or no treatment but the corticosteroid was significantly more effective than cyclosporine.

Histocompatibility antigen and passenger cell content of normal and diseased human cornea.

The outcome of clinical corneal transplantation depends on the degree of vascularization and inflammation present in the graft bed at the time of the operation, but the reason for this is unclear. Normal, diseased, and rejected human corneas have been examined with an immunoperoxidase staining procedure, employing monoclonal antibodies to class I and II major histocompatibility complex (MHC) antigens and to other leukocyte markers. In particular, departures from normal in the expression of MHC antigens and in the passenger cell distribution in the diseased or rejected corneas were sought.

Penetrating corneal transplantation in the inbred rat: a new model.

A model of orthotopic penetrating keratoplasty has been developed in the inbred rat using both avascular and prevascularized recipient beds. The surgical procedure is conventional and can be achieved with standard instrumentation. Isografts into avascular recipient beds (Fisher 344 into Fisher 344 strain combination) were successful and survived indefinitely with excellent corneal function judged either visually by clarity and lack of oedema, or histologically at autopsy.