Aqueous and vitreous penetration of levofloxacin after oral administration.

OBJECTIVE: To investigate the penetration of levofloxacin, an optical S-(-)isomer of ofloxacin, into the aqueous and vitreous humor after oral administration. DESIGN: Randomized, clinical trial comparing tissue levels of levofloxacin after one or two doses 12 hours apart. PARTICIPANTS: Forty-five patients undergoing initial vitrectomy between February 1997 and June 1997 at the UIC Eye Center. METHODS: Aqueous, vitreous, and serum samples were obtained and later analyzed from 45 patients after oral administration of 1 500-mg tablet (group 1, 22 patients) or 2 500-mg tablets (group 2, 23 patients) 12 hours apart before surgery. MAIN OUTCOME MEASURES: Aqueous, vitreous, and serum concentrations of levofloxacin (micrograms/milliliter). RESULTS: Group 1 achieved mean aqueous, vitreous, and serum levels of 0.59 +/- 0.48 microg/ml, 0.32 +/- 0.34 microg/ml, and 4.34 +/- 3.59 microg/ml, respectively. Group 2 achieved mean aqueous, vitreous, and serum levels of 1.90 +/- 0.97 microg/ml, 2.39 +/- 0.70 microg/ml, and 8.02 +/- 3.14 microg/ml. CONCLUSIONS: Mean inhibitory aqueous and vitreous MIC90 levels were achieved against a majority of ocular pathogens, including Staphylococcus aureus and Staphylococcus epidermidis, Streptococcus pneumoniae (vitreous), Bacillus cereus (vitreous), Haemophilus influenzae, Moraxella catarrhalis, and most gram-negative aerobic organisms except Pseudomonas aeruginosa after two doses given 12 hours apart. Mean MIC90 levels were obtained in the vitreous for a majority of pathogens responsible for traumatic, postoperative, or bleb-related endophthalmitis.

Intraocular penetration of gentamicin after once-daily aminoglycoside dosing.

BACKGROUND: Intraocular concentrations-particularly intravitreal concentrations-after systemic administration of gentamicin are poor. Once-daily aminoglycoside dosing of intravenous gentamicin achieves peak serum levels up to five times higher than conventional dosing. Whether these increased serum levels of gentamicin improve the aqueous or vitreous concentrations in humans has not been determined. The authors sought to determine if the intraocular penetration of gentamicin would be improved using this method. METHODS: Patients undergoing vitrectomy procedures were administered intravenous gentamicin in a dose of 7 mg/kg approximately 1 hour before surgery. An adjustment in dosing was made for anyone more than 20% over his or her ideal body weight. Aqueous, vitreous, and serum samples were collected before any intraocular surgical manipulation. The samples were analyzed by fluorescence polarization immunoassay (TDx system). RESULTS: The average single gentamicin dose was 498 mg (range, 360-700 mg). The aqueous, vitreous, and serum levels averaged 1.14 microg/mL, 0.41 microg/mL, and 22.07 microg/mL, respectively. No correlation between serum level concentrations and time of administration was found for the aqueous and vitreous levels in this study. CONCLUSION: Although the average peak serum level of gentamicin was five times higher than previously reported, the vitreous levels averaged only 1.5 times higher. The blood-retinal barrier is difficult to penetrate even when higher serum levels are achieved. Due to its poor ocular penetration, gentamicin may not be among the best drugs for prophylaxis of penetrating eye injuries, surgical prophylaxis, or treatment of endophthalmitis.

Uveal melanomas in black patients: a case series and comparative review.

Uveal melanomas are rare in black patients. Of a total of 2586 patients with the diagnosis of posterior uveal melanoma who were managed in the Oncology Service at Wills Eye Hospital from 1974 to 1987, 10 patients (0.39%) were black. Data on patient age (mean: 53.9 years), sex (male-to-female ratio: 7:3), and relative frequency of disease between black (0.39% of total cases) and white patients were similar to that of previous reports. The distinguishing characteristics (incidence, risk factors, complications, and prognostic indicators) of uveal melanoma in black versus white patients also were reviewed.

Cytological changes associated with tubo-endometrioid metaplasia of the uterine cervix.

Two women who had undergone previous cervical surgery for the treatment of glandular intraepithelial neoplasia (GIN) and cervical intraepithelial neoplasia (CIN), were found to have severely dyskaryotic cells of glandular and metaplastic type in follow-up cervical smears. A third patient was found to have similar abnormal cells in a routine screening smear. All of the patients were subjected to either hysterectomy or cervical conization and in all cases histological examination showed tubo-endometrioid glands in the endocervix, well away from the uterine isthmus, with no associated endometrial stromal tissue. All of the cervical smears were reviewed and cytological features that facilitate the distinction between tubo-endometrioid metaplasia and squamous or glandular dyskaryosis were identified. These features include the smaller size of affected cells, more marked nuclear hyperchromasia, inconspicuous nucleoli, the formation of glandular structures, the lack of discrete squamous dyskaryosis and the absence of the typical 'feathering' noted with GIN. The possibility of tubo-endometrioid metaplasia should be considered when atypical glandular or metaplastic cells are noted in cervical smears, particularly, but not exclusively, in women who have been treated for CIN or GIN. In the presence of these changes clinicians should rebiopsy the cervix before embarking on further unnecessary surgery which may adversely affect fertility and pregnancy, particularly in younger patients.