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Biomedical subjects

I Avni

Publications and source records attributed to I Avni.

At least 19 recordsLinked to original sources
PubMed2004

Human corneal stromal tissue concentration after consecutive doses of topically applied 3.3% vancomycin.

AIMS: To evaluate vancomycin penetration into human corneal stromal tissue in patients treated with topical vancomycin eyedrops before penetrating keratoplasty (PKP). METHODS: Twenty four patients who underwent PKP, seven patients with keratoconus (group 1) and 17 patients with corneal scar or corneal decompensation (group 2). All patients received topical application of vancomycin eyedrops (concentration: 33 mg/ml) 10, 3, 2, 1 hour, and 15 minutes before the operation. Corneal cumulative vancomycin levels were assessed by bioassay. RESULTS: Mean vancomycin corneal stromal tissue concentration was 46.7 (SE 4.11) microg/g tissue. This value was four to 20-fold in excess of the MIC90 of vancomycin in Staphylococcus aureus (2-10 microg/ml). CONCLUSIONS: Vancomycin reached high corneal tissue concentrations that significantly exceeded the MIC90 (2-10 microg/ml) for most key Gram positive corneal pathogens. The ratio of vancomycin stromal concentration to protein concentration was statistically higher in group 2 (non-keratoconus).

Adult↗
PubMed2003

Unrecordable pulsatile ocular blood flow may signify severe stenosis of the ipsilateral internal carotid artery.

AIM: To examine the relation between stenosis of the internal carotid artery (ICA) and pulsatile ocular blood flow (POBF). METHODS: In 57 eyes of 30 patients who were referred for Doppler ultrasound examination of the ICA we measured POBF and analysed the correlation with degree of ipsilateral ICA stenosis. RESULTS: There was a significant negative correlation between POBF and ipsilateral ICA stenosis (Pearson correlation coefficient, r=-0.516, p<0.0001). In 14 eyes POBF could not be measured by the OBF tonometer, and in 11 of these cases (79%) severe stenosis (>75%) of the ipsilateral ICA was present. When these eyes were excluded from analysis, there was no correlation between POBF and ICA stenosis (r=-0.02, p=0.91). Among these 43 eyes in which POBF could be measured it ranged 667-2095 microl/min with a mean of 970.72 microl/min. CONCLUSION: Low or unrecordable POBF may signify severe stenosis of the internal carotid artery. POBF is not a direct reflection of ipsilateral ICA blood flow.

Aged↗
PubMed2001

Corneal surface changes after pars plana vitrectomy and scleral buckling surgery.

PURPOSE: To evaluate the changes in corneal shape after pars plana vitrectomy, encircling buckling surgery, and a combination of the 2 procedures. SETTING: Assaf Harofeh Medical Center, Zrifin, and Goldshlager Eye Institute, Tel Hashomer, Israel. METHODS: In a prospective clinical study, 61 eyes of 61 patients were assigned to 1 of 3 groups based on the type of procedure: pars plana vitrectomy, encircling buckle and pars plana vitrectomy, or encircling buckle. The eyes had corneal keratometry (TMS-1), visual acuity measurement, and videokeratography (TMS-1) preoperatively and 2 days, 1 week, and 1 and 3 months postoperatively. The topographic parameters statistically analyzed were the corneal surface cylinder, simulated keratometry, surface regularity index, surface asymmetry index, standard deviation of corneal power, average corneal power, and irregular astigmatism index. RESULTS: The measurements of all topographic indices were statistically significantly different from baseline measures 2 and 7 days postoperatively in all 3 groups. However, at 1 and 3 months, there was no significant difference from preoperatively in any index. Postoperative best corrected visual acuity was statistically significantly different from preoperatively. CONCLUSIONS: All corneal surface indices were significantly altered after all 3 types of surgery. Corneal surface measurements returned to preoperative values by 1 month postoperatively and remained stable until the final follow-up at 3 months.

Adolescent↗
PubMed2000

The incidence of hepatitis C virus positive serological test results among cornea donors.

Purpose. We have noticed that the incidence of positive serological tests of hepatitis C virus (HCV) among cornea donors in our eye bank is higher than expected. The purpose of this study was to determine the incidence of these positive findings and identify the contributory risk factors.Methods. All corneas procured between June 1993 and June 1997 were included in this retrospective study. In all cases a routine work-up, including serological testing of donors' sera and evaluation of the procured corneas, was performed prior to corneal transplantation. Donors found to be positive for HCV antibodies were compared to our general population of corneal donors, with respect to the demographic, serological and ophthalmological data obtained during the transplantation work-up.Results. All 851 corneas procured from 438 donors were included. Antibodies to HCV were found in 29 donors (6.6%). Following positive test results, 57 corneas (6.7%) were discarded. The time from donors' death to cornea procurement was significantly longer among HCV-positive patients than in the general donor population (12.3 vs. 9.3 h, p<0.0003). No other differences were detected between the two groups.Conclusion. Delay in harvesting of donated corneas may give rise to false positive HCV-antibodies test results, which may be partially responsible for the high rate of positive findings among cornea donors, with consequent tissue wastage.

Journal Article↗
PubMed2000

The reculture technique: individualizing the treatment of Acanthamoeba keratitis.

PURPOSE: To assess the efficacy of three drugs in different concentrations against different strains of Acanthamoeba using the reculture technique. METHODS: Cysts and trophozoites were immersed in five separate solutions. The solutions administered included 0.1% and 0.02% polyhexamethylene biguanide (PHMB), 0.1% and 0.02% chlorhexidine, and propamidine isethionate (Brolene). Readings took place after 1, 5, and 24 hours. The cysts and trophozoites were then recultured for an additional period of 48 hours. An effective drug was defined as a medication that inhibited any growth of trophozoites using the reculture technique. RESULTS: Chlorhexidine at concentrations of 0.1% and 0.02% was the only effective drug against all five strains of Acanthamoeba examined, and no trophozoites were detected on plates immersed with this agent. Only 0.1% chlorhexidine was effective in destroying all cysts in the five strains examined. CONCLUSION: We found that 0.02% chlorhexidine was efficient in irradicating all trophozoites and 0.1% chlorhexidine was effective in eradicating all cysts in the samples we examined. Therefore, it may be possible that 0.02% chlorhexidine is a good initial treatment in amoebic keratitis. Sensitivity testing, then, may be performed using the reculture technique and specification of therapy can be made accordingly.

Acanthamoeba↗
PubMed1997

Persistent chlorpromazine deposits in donor corneal tissue after corneal transplantation.

PURPOSE: To present unusual cases with corneal graft deposits and discuss eye bank criteria concerning donors treated with phenothiazines. METHODS: We examined two patients with unusual corneal graft deposits after uneventful corneal transplantation. Donors' files and eye bank procedures were reviewed. RESULTS: Fine corneal endothelial punctate deposits were detected in both corneal grafts and did not resolve in the following 18 months. CONCLUSION: To our knowledge, this is the first case report documenting transplantation of corneas with chlorpromazine deposits. Delicate corneal findings can be missed before transplantation.

Adult↗
PubMed1994

Sjogren's syndrome in Israel: primary versus secondary disease.

Sixty Israeli patients, 30 with primary Sjögren's syndrome (SS) and 30 with rheumatoid arthritis (RA) and secondary SS, were evaluated. The Schirmer-1 test and a positive labial salivary gland biopsy were found to be the most helpful tools in assessing the diagnosis of SS. Extraglandular features such as Raynaud's phenomenon, lymphadenopathy and CNS involvement as well as parotid gland enlargement (p < 0.05) were more common in primary SS. Antinuclear antibodies, especially anti-Ro (SSA) and anti-La (SSB) were also more common in primary SS (p < 0.05). Our results are in accord with those of many European centers, despite the different genetic background.

Adult↗
PubMed1994

Using an anterior chamber maintainer to control intraocular pressure during phacoemulsification.

We describe a phacoemulsification technique that uses an anterior chamber maintainer (ACM) to control intraocular pressure. Continuous irrigation through the ACM maintains pressurized intraocular conditions throughout surgery and when the automated system is not activated. Intraocular pressure is stabilized at predetermined levels with minor fluctuations. Viscoelastics can be used in conjunction with the ACM.

Anterior Chamber↗
PubMed1994

Proximity-sensor dimmer device as an aid in the reduction of operating microscope-induced retinal phototoxicity.

The length of exposure to the light source of the operating microscope is a major factor determining retinal phototoxicity. In our experience, for about 20% of the time during cataract surgery, the surgeon is not looking through the oculars. To take advantage of these times, we designed a device, a proximity switch consisting of an infrared sensor mounted between the oculars in the operating microscope. When the surgeon's forehead approaches the microscope to look through the oculars, the sensor increases the illumination; when the surgeon moves away, it is automatically reduced. The resulting decreased overall exposure to light may reduce retinal phototoxicity.

Cataract Extraction↗
PubMed1993

[Acanthamoebic keratitis].

Acanthamoebic keratitis is still a rare infection. It occurs in contact lens-wearers, especially when saline is prepared at home from contaminated tap water. There are periods of remission, and occasionally misleading findings resembling those of herpetic keratitis, which make the diagnosis difficult. The isolation of the acanthamoeba is not easy and special culture media are required. Early recognition and aggressive therapy with antiamebic medication and epithelial debridement, often in conjunction with penetrating keratoplasty, are needed. We describe the clinical course, laboratory diagnosis and treatment of 3 patients with acanthamoebic keratitis, 2 men aged 20 and 25, respectively and a women aged 42.

Acanthamoeba Keratitis↗