Hadas Mechoulam

Iontophoresis–gentamicin delivery into the rabbit cornea, using a hydrogel delivery probe

PURPOSE To evaluate the efficacy of penetration of gentamicin into the cornea of rabbits using iontophoresis with a hydrogel-gentamicin containing probe. METHODS Eight of 10 groups (groups 3-10) of 6 rabbits (one eye per rabbit), underwent corneal iontophoresis using soft stable hydroxyethyl methacrylate hydrogel discs (80% water content) loaded with gentamicin sulphate which were mounted on an iontophoresis probe. The studied current intensities were 0, 0.1, 0.3 and 0.6 mAmp, and the durations of iontophoresis were 10 and 60 sec. Two control groups received 1.4% topical drops of gentamicin every 5 min for 1 hr (group 1) or sub-conjunctival injection of 10 mg gentamicin (group 2). Following sacrifice, aqueous humour was taken, corneas were excised, and gentamicin concentration was determined in aqueous humour and cornea samples. RESULTS Post-iontophoresis, the concentration of gentamicin in the corneas ranged from high (88.60 +/- 38.64 microg ml(-1)) to very low (0.10 +/- 0.89 microg ml(-1)). Both the control groups and those rabbits treated with current intensity of 0.1 mAmp or greater obtained therapeutic gentamicin levels in the corneas. Use of iontophoresis for 60 sec or current intensity greater than 0.1 mAmp obtained corneal gentamicin levels not different from sub-conjunctival injection. Application of current intensity of 0.1 mAmp or greater gave corneal gentamicin concentrations comparable to topical application of the drug, except when 0.6 mAmp were used for 60 sec (p = 0.05). Increasing current intensity or duration of iontophoresis significantly increased (p = 0.001 for both) gentamicin penetration into the cornea. Current intensity had more influence (Beta2 = 0.40) than duration (Beta2 = 0.13) on drug penetration. A significant interaction was found between the duration of iontophoresis and the current intensity. Very small or no concentrations of the drug were discovered in the anterior chambers of rabbits. CONCLUSIONS Iontophoresis using hydrogel-gentamicin probe may deliver therapeutic concentrations of gentamicin into the cornea.

Forty years of changing indications in penetrating keratoplasty in Israel.

Purpose: To examine the leading indications for keratoplasty and identify the changing trends in the past 40 years in Israel. Methods: Pathology reports of all penetrating keratoplasties (PKPs) performed at Hadassah-Hebrew University Hospital from 1961 to 2000 were reviewed. We evaluated the indications for keratoplasty in each decade between the years 1961 and 2000. Results: During the 40-year period, a total of 1681 PKPs were performed. Keratoconus (n = 478, 28.4%) was the most common indication, followed by graft failure (n = 226, 13.4%), pseudophakic corneal edema (PCE) (n = 142, 8.4%), herpetic infections (n = 125, 7.4%), nonherpetic infections (n = 114, 6.8%), scarring (n = 113, 6.7%), and trauma (n = 110, 6.5%). The 7 groups account for approximately 77.5% of all keratoplasties performed. Ocular infections were the most common indications before 1970 and have been declining ever since. Keratoconus became the leading indication in the past 30 years. In the past decade, of 663 keratoplasties, keratoconus was the most common indication (56, 38.6%) followed by graft failures/rejections and PCE (the second most common indication between the years 1981 and 1990). Conclusions: Keratoconus was the leading indication for keratoplasty in our series. There was a decreasing trend in PK for ocular herpetic infections during the decades. The rate of PCE decreased while failed graft became the second most common indication for PKP during the past decade.

Iontophoretic treatment of experimental pseudomonas keratitis in rabbit eyes using gentamicin-loaded hydrogels.

Purpose: To evaluate the efficacy of iontophoresis using a hydrogel probe containing gentamicin for the treatment of Pseudomonas keratitis in the rabbit cornea. Methods: Five groups (Groups 1-5) of 8 rabbits each were infected by injecting Pseudomonas aeruginosa into their corneas. Three dosings of corneal iontophoresis were performed, at intervals of 3.5 hours, using soft disposable gentamicin-loaded hydroxyethyl methacrylate hydrogel discs mounted on a portable iontophoretic device. Groups 1 and 2 were treated with corneal iontophoresis for 60 seconds and a current of 0.5 and 0.2 mA. Groups 3 and 4 were treated with hydrogel loaded with 0.9% NaCl solution, using a current of 0.2 mA and mock iontophoresis. Group 5 was treated with eye drops of 1.4% gentamicin every hour for 8 hours. One and a half hours after the last treatment, the animals were killed, and the corneas were excised and cultured for P. aeruginosa count after 24-hour incubation. Results: After iontophoretic treatment of gentamicin with a current of 0.5 mA (Group 1), the logarithmic value of Pseudomonas colony-forming units (CFUs) was 2.96 ± 0.45. After lower current iontophoretic treatment (Group 2), the logarithmic Pseudomonas count was 5.25 ± 0.54 CFUs. At the control groups (Groups 3-5), the Pseudomonas counts were found to be much higher, 7.62 ± 0.28, 7.22 ± 0.29, and 6.29 ± 0.45 CFUs, respectively. Conclusion: A short iontophoretic treatment using gentamicin-loaded hydrogels has potential clinical value in treating corneal infections.

Expression and activation of toll-like receptor 3 and toll-like receptor 4 on human corneal epithelial and conjunctival fibroblasts

BackgroundToll-like receptors (TLRs) are recognized as important contributors to the initiation and modulation of the inflammatory response in the eye. This study investigated the precise expression patterns and functionality of TLRs in human corneal epithelial cells (HCE) and in conjunctival fibroblasts (HCF).MethodsThe cell surface expression of TLRs 2-4, TLR7 and TLR9 in HCE and HCF was examined by flow cytometry with or without stimulation with lipopolysaccharide (LPS) or polyinosinic:polycytidylic acid (poly I:C). The mRNA expression of the TLRs was determined by real-time PCR. The protein content levels of interleukin (IL)-6, IL-8, IL-1β and tumor necrosis factor-α (TNF-α) were measured in HCE and HCF using multiplex fluorescent bead immunoassay (FBI).ResultsThe surface expression of TLR3 and TLR4 was detected on both HCE and HCF. Following incubation with LPS, the percentage of HCE cells staining for TLR4 decreased from 10.18% to 0.62% (P < 0.001). Incubation with poly I:C lowered the percentage of HCE cells positive for TLR3 from 10.44% to 2.84% (P < 0.001). The mRNA expression of TLRs2, 4, 7 and 9 was detected in HCE only. Activation of HCE with LPS complex elicited protein secretion up to 4.51 ± 0.85-fold higher levels of IL-6 (P < 0.05), 2.5 ± 0.36-fold IL-8 (P > 0.05), 4.35 ± 1.12-fold IL-1β (P > 0.05) and 29.35 ± 2.3-fold TNFα (P < 0.05) compared to cells incubated in medium.ConclusionsHCF and HCE both express TLRs that respond to specific ligands by increasing cytokine expression. Following activation, the surface expression of TLR3 and TLR4 on HCE is decreased, thus creating a negative feedback loop, mitigating the effect of TLR activation.

Astigmatism after mersilene and nylon suture use for penetrating keratoplasty.

Purpose: To evaluate postoperative astigmatism after the use of Mersilene and nylon sutures for penetrating keratoplasty. Methods: Two groups of 12 patients each (age, 20-50 years) suffering from keratoconus underwent penetrating keratoplasty. Continuous suturing combined with 12 interrupted sutures was used in each case: Mersilene 11-0 sutures were used in group 1, whereas nylon 10-0 sutures were used in group 2. Sutures were removed to control astigmatism when required. All patients were monitored for 36 months. Results: During the follow-up period, sutures were removed in each eye as indicated by astigmatism or breakage. In group 1 (Mersilene 11-0 sutures), no breakage of sutures was recorded. In group 2 (nylon 10-0 sutures), breakage of sutures was recorded in 11 of 12 cases. However, continuous sutures were removed in 2 patients in group 2. After the first year, the astigmatism remained within ±1.00 diopter in all except 1 patient in group 1 and in 5 patients in group 2. No suture-related complications were recorded except for scarring with photophobia in 1 patient in group 1 and suture breakage in 11 eyes in group 2. Conclusion: Mersilene sutures can provide a stable postoperative astigmatism, whereas nylon sutures have a tendency to break and cause changes in corneal astigmatism.

Congenital cytomegalovirus infection and Wiskott-Aldrich syndrome successfully treated with unrelated cord blood transplantation.

We report a successful umbilical cord blood transplantation (UCBT) in an 8‐month male with Wiskott–Aldrich syndrome (WAS) and congenital cytomegalovirus (CMV) infection. The child presented at 3 months of age with symptomatic thrombocytopenia and CMV infection. Despite appropriate antiviral treatment no rise in the platelet count was observed. Genetic analysis confirmed the diagnosis of WAS. The clinical course was complicated by severe CMV retinitis with bilateral retinal hemorrhages and renal vasculitis. He underwent unrelated UCBT resulting in a rapid resolution of autoimmunity and thrombocytopenia. Pediatr Blood Cancer 2011; 57: 681–683.

Ophthalmologic Findings in H Syndrome: A Unique Diagnostic Clue

Abstract Background: H syndrome is an autosomal recessive histiocytosis with multisystemic involvement caused by mutations in the SLC29A3 gene. The term H syndrome was coined to denote the major clinical findings which include hyperpigmentation, hypertrichosis, hearing loss, hepatosplenomegaly, hypogonadism, hyperglycemia/diabetes mellitus and hallux valgus/flexion contractures. Almost 100 individuals affected with this disorder have been reported, however, a thorough evaluation of the ophthalmologic features of H syndrome has not yet been performed. Materials and Methods: Ophthalmic examination of a 50-year-old male with H syndrome. Mutation analysis of SLC29A3 was also performed in this patient. Results: Ophthalmic findings included; shallow orbits with exorbitism, bilateral pterygium, limbal thickening, corneal arcus and cortical cataract. We also review ophthalmologic findings in previously reported H syndrome patients. Conclusions: The presence of dilated lateral scleral vessels, corneal arcus and shallow orbits should raise the suspicion of H syndrome, especially when seen in young age.