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Biomedical subjects

J P Guzek

Publications and source records attributed to J P Guzek.

10 recordsLinked to original sources
PubMed1998

Rabbit Streptococcus pneumoniae keratitis model and topical therapy.

PURPOSE: To develop a model for experimental Streptococcus pneumoniae keratitis and to evaluate the chemotherapeutic efficacy of 12 common topical antibiotics in vivo. METHODS: Five-hundred (CFUs of log-phase S. pneumoniae were injected into the central corneal stroma of 36 eyes of 18 rabbits. After 0, 4, 8, 16, 24, and 48 hours, the in vivo growth was assayed as the CFU per cornea. Epithelial removal (to promote antibiotic entry and mimic human keratitis) was evaluated. Disc or tube dilution verification of the sensitivity or resistance of three S. pneumoniae strains was performed: a penicillin sensitive ("S"), an intermediate sensitive ("I"), and a resistant ("R") strain. Keratitis was established with S. pneumoniae "S" in 65 eyes, S. pneumoniae "I" in 107 eyes, and S. pneumoniae "R" in 78 eyes. Sixteen hours later, control corneas were harvested and the epithelium removed from treatment corneas. Every half hour saline, penicillin, gentamicin, bacitracin, ciprofloxacin, ofloxacin, erythromycin, vancomycin, ceftriaxone, cefotaxime, or chloramphenicol was applied for 5 hours. One hour later CFUs/cornea were assayed. RESULTS: After 24 hours, S. pneumoniae "S" and "I" had proliferated to 9.18+/-6.65 x 10(6) CFUs and 9.26+/-6.90 x 10(6) CFUs. Epithelial removal at 16 hours was not significant. The in vitro antibiotic sensitivity was as expected. However, in vivo, penicillin, gentamicin, or cefazolin sterilized S. pneumoniae "S." S. pneumoniae "R" responded best to fortified gentamicin with or without vancomycin; all others antibiotics were significantly less effective (P < 0.001). CONCLUSIONS: A small intracorneal S. pneumoniae inoculum in rabbit corneas grew and was maintained for 24 hours (with epithelial removal) to provide a model for testing antibiotic sensitivity in vivo. Topical penicillin is best for treating keratitis from penicillin-sensitive S. pneumoniae, whereas topical gentamicin or a combination of gentamicin and vancomycin was most effective against penicillin-resistant S. pneumoniae.

Administration, Topical↗
PubMed1998

The effect of vehicle on corneal penetration of triturated ketoconazole and itraconazole.

BACKGROUND AND OBJECTIVES: Triturated (crushed and suspended) ketoconazole has been recommended for the treatment of fungal keratitis when commercial antifungal eyedrops are unobtainable. The authors evaluated the in vivo corneal stromal concentration with different vehicles in the eyes of adult rabbits. MATERIALS AND METHODS: Ketoconazole and itraconazole tablets were triturated to 20 mg/ml in four vehicles: polyvinyl alcohol (PVA), boric acid, olive oil, and balanced salt solution (BSS). Six eyes (deepithelialized for better penetration) received one drop every 15 minutes for 2 hours. A yeast overlay bioassay of extracts determined the stromal concentration. RESULTS: Itraconazole in BSS, olive oil, PVA, and boric acid produced inhibition zones of 17.3, 15.6, 15.4, and 13.2 mm, respectively. Ketoconazole produced inhibition zones of 35.9, 39.4, 41.8, and 44.7 mm, respectively. From a standard curve, the concentrations of ketoconazole in tissue were 512, 773, 1221, and 1492 micrograms/g, respectively. CONCLUSION: The vehicle that is used to triturate antifungals affects the tissue concentration. This may have an impact on fungal keratitis therapy.

Animals↗
PubMed1997

Clinical and radiologic lacrimal testing in patients with epiphora.

OBJECTIVE: The purpose of the study is to assess the strengths and weaknesses of selected clinical and radiologic lacrimal tests in patients with epiphora. DESIGN: The study design was a prospective clinical trial. PARTICIPANTS: Fifteen patients with epiphora (N = 27 eyes) were studied. METHODS: All patients underwent Jones testing, the dye disappearance test, canalicular probing, lacrimal scintigraphy, and macrodacryocystography. MAIN OUTCOME MEASURES: The dye disappearance test was graded individually by three ophthalmologists. Lacrimal scintigraphy and macrodacryocystography were evaluated by a nuclear medicine specialist and a radiologist, respectively. A panel of three ophthalmologists evaluated the data using a scoring system that relied on the preponderance of evidence to arrive at a final assessment. RESULTS: When the Jones I test results were negative (dye recovered from the nose), the epiphora was always from hypersecretion. When the Jones I test results were positive (no dye recovered from the nose), obstruction was not always present. When the dye disappearance test results were strongly abnormal, obstruction was always present. In contrast, when the dye disappearance test results were normal, the lacrimal drainage system was not always patent. Canalicular probing was more reliable than scintigraphy in identifying canalicular obstruction. Marked stenosis of the sac or duct on dacryocystography essentially confirmed nasolacrimal outflow obstruction; however, with the authors' technique, a normal study was found in some patients with functional or partial obstruction. CONCLUSIONS: More than one lacrimal test may be required for a definitive diagnosis in patients with epiphora due to partial or functional nasolacrimal outflow obstruction.

Aged↗
PubMed1994

Serious occurrences in the natural history of advanced climatic keratopathy.

BACKGROUND: Climatic or chronic actinic keratopathy is an important corneal degeneration occurring after prolonged climatic exposure. The advanced stages of disease are confined generally to tropical or arid localities (including the Arctic) with high levels of sunlight. After many years of disease evolution, the advent of stage 3 keratopathy often presages a rapid downhill course. The instability of advanced climatic keratopathy has received little attention. METHODS: Eighteen patients with advanced climatic keratopathy are described from the Transvaal region in South Africa and from Saudi Arabia. Patients with rapid disease progression, spontaneous sterile ulceration, and secondary microbial keratitis are described. RESULTS: The rapid progression characteristic of stage 3 climatic keratopathy is illustrated. Severe, focal, sterile ulceration of the devitalized corneal degeneration may be common. Secondary infection may occur, leading to rapid dissolution of the climatic keratopathy material. Corneal perforation may ensue. The occurrence of yellow or brown fragments of the climatic keratopathy within or adjacent to the corneal inflammatory infiltrate indicates the predisposing cause of the infection, as usually also with examination of the opposite eye. CONCLUSIONS: These observations emphasize the inherent instability of advanced climatic keratopathy, which frequently takes a relentless downhill course. In rural populations of the developing world, climatic keratopathy is an important cause of blindness. Disease pathogenesis, treatment, and prevention deserve greater study.

Adult↗
PubMed1994

Comparison of topical ciprofloxacin to conventional antibiotic therapy in the treatment of experimental Pseudomonas aeruginosa keratitis.

We evaluated the efficacy of topical ciprofloxacin (3.0 mg/ml) in the treatment of experimental Pseudomonas aeruginosa keratitis in 60 rabbits. We compared ciprofloxacin treatment with double drug therapy consisting of tobramycin (13.6 mg/ml) plus polymyxin B (25,000 U/ml) or carbenicillin (6 mg/L). Two strains of P. aeruginosa were used. One was a strain well characterized for use in experimental Pseudomonas keratitis (ATCC organism 27853); the second was an organism from a patient with a Pseudomonas corneal ulcer. Rabbits were treated for 16 h, after which the corneas were excised, homogenized, and plated serially for residual colony-forming units. Both organisms responded significantly better to topical off-the-shelf ciprofloxacin than to therapy with two conventional antipseudomonal fortified antibiotic drugs (p < or = 0.0001).

Administration, Topical↗
PubMed1994

Lacrimal testing. Age as a factor in Jones testing.

PURPOSE: A modified Jones test is used to assess whether lacrimal transit time varies with age. METHODS: The right eyes of 101 control subjects and 18 patients suspected of having lacrimal system abnormalities were tested with one drop of 2% sodium fluorescein solution. A cotton applicator was placed in the nose next to the inferior turbinate and participants were asked to lean forward. Dye passage was assessed every 3 minutes for 24 minutes. RESULTS: The results were assessed by age. In control subjects, there seemed to be a natural break in the distribution of the data at the age of 45 to 50 years. In control subjects younger than 45 years of age, 10/11 (91%) passed dye in 6 minutes or less (median = 3 minutes), whereas in those 45 years of age and older, 79/90 (84%) passed dye in 12 minutes or less (median = 6 minutes). The results were statistically significant (P = 0.0091). In contrast, patients with symptoms of epiphora due to a nasolacrimal duct obstruction had lacrimal transit times in excess of the above limits. CONCLUSION: This study confirms that the lacrimal transit time slows with age. The modification of the Jones test presented here requires a cutoff of 6 minutes in patients younger than 45 years of age and 12 minutes in patients 45 years of age and older.

Adult↗
PubMed1987

Risk factors for intraoperative complications in 1000 extracapsular cataract cases.

A prospective study of the risk factors in extracapsular surgery was carried out between October 1984 and April 1986. One thousand extracapsular cataract extractions were performed by seven physicians. Decreasing pupil size was the only statistically significant risk factor for vitreous loss (P = 0.0002). Zonular breaks occurred more commonly with pseudoexfoliation syndrome (PX) (P less than 0.0001), with decreasing pupil size (P less than 0.0001), and with one surgeon who used the Simcoe aspirating needle (Storz) exclusively (P = 0.0001). It is acknowledged that it is very difficult to standardize what constitutes a small zonular break; hence, the increase in zonular breaks recorded by this surgeon may have been due only to his using less stringent criteria than the others. Capsule breaks had no significant risk factors at the 0.01 level. High myopia, advanced cataract, glaucoma, advanced age, and diabetes mellitus were not found to be risk factors for vitreous loss, zonular breaks, or capsular breaks.

Adult↗
PubMed1984

Effects of topical betaxolol in ocular hypertensive patients.

Betaxolol, a new beta 1-adrenergic blocker, was applied to 20 eyes of ten patients with ocular hypertension. Topical 0.25% betaxolol was found to significantly lower intraocular pressure compared with placebo. There were no subjective or objective ocular or systemic side effects detected. There were no changes in pulse rate, BP, or corneal sensitivity. Betaxolol may be useful in patients with asthma, chronic bronchitis, and certain cardiovascular diseases where timolol maleate therapy may be contraindicated.

Administration, Topical↗