The role of cultures in the management of ulcerative keratitis.
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Anti-Bacterial Agents↗
Biomedical subjects
S D McLeod
Publications and source records attributed to S D McLeod.
Iris-sutured posterior chamber lens dislocation late after penetrating keratoplasty.
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Adult↗
Knowledge or noise. Scientific publication and the electronic journal.
Over the last few years, the Internet has grown exponentially and is developing a role in the exchange of scientific information. However, a number of problematic issues are associated with electronic publications, including limited transmission speed, undependable file longevity, poorly documented postpublication editing, copyright infringement, and cultural impediments to acceptance. By measure of citation frequency, electronic journals seem to have limited influence within scientific discourse, but this medium is as yet in its infancy. Since electronic publication enjoys many potential advantages over traditional print publication, it is expected to gain far greater influence over time. The American Medical Association group of publications recognizes this and intends to develop its electronic publications with attention to maintaining traditional critical scientific standards.
American Medical Association↗
Differential care of corneal ulcers in the community based on apparent severity.
PURPOSE: To describe current practice patterns in treating infectious keratitis. METHODS: A questionnaire was designed that asked ophthalmologists to describe the diagnostic equipment accessible to their practice for performing smears and obtaining scrapings for microbial culture and sensitivity testing. The questionnaire also presented two hypothetical cases of patients with infectious keratitis. Bacterial keratitis was relatively early and less severe in the first patient, and it was more advanced and more severe in the second patient. Recipients were asked about their diagnostic and therapeutic approach. The survey was mailed to 300 ophthalmologists in Florida, Illinois, and New York. RESULTS: One hundred twenty-four completed surveys (45%) were returned. Six surveys were from cornea specialists, who were excluded from the analysis. Only 18 practices (15%) maintained access to Gram stain supplies, and 58 (50%) maintained culture supplies. Whereas 56% of respondents would treat the patient with the less severe bacterial keratitis without obtaining samples for cultures, only 13% would treat the patient with the more severe condition in this manner (P<0.00001). Of the respondents, 82% would treat the patient with the less severe bacterial keratitis with a fluoroquinolone, compared with 62% for the patient with the more severe infection (P=0.002). The mean frequency of fluoroquinolone administration for the patient with more-severe bacterial keratitis was one drop every 0.88 hours, compared with one drop every 1.48 hours for the patient with the less severe infection. CONCLUSIONS: Ophthalmologists appear to treat suspected infectious keratitis differently, depending on perceived severity; they choose different antibiotic regimens; and are more likely to forgo scrapings for Gram staining and cultures for ulcers that appear less severe. The justification for this approach should be established.
Adult↗
The role of smears, cultures, and antibiotic sensitivity testing in the management of suspected infectious keratitis.
PURPOSE: To examine the role of routine smears, cultures, and antibiotic sensitivity testing in the treatment of suspected infectious keratitis. METHODS: A retrospective chart and laboratory data review was performed for 81 consecutive patients seen in the Los Angeles County/University of Southern California Department of Ophthalmology between June 1991 and December 1993 with a primary diagnosis of community-acquired infectious keratitis. No patients were treated with antibiotics before evaluation in the author's department, and all underwent corneal scrapings for gram-stain and bacterial, fungal, and mycobacterium cultures. Ulcers were classified as moderate or severe. All initially were treated as inpatients with a regimen including fortified cefazolin and a fortified aminoglycoside. RESULTS: Of 81 patients, 74 ulcers were either culture- negative (n=18) or grew bacteria (n=56). Fungal infection was suggested in seven patients. Of the nonfungal ulcers, 33 were classified as moderate, and 41 as severe; all moderate ulcers improved without requiring a modification in antibiotic treatment, whereas 3 severe ulcers required a change in treatment. CONCLUSION: Most community-acquired bacterial ulcers resolve with broad spectrum empiric therapy. Alternatives to universal culture and sensitivity testing that might be considered include selectively performing cultures for more severe or suspected non-bacterial ulcers or routinely obtaining cultures in all cases, but pursuing identification and sensitivity studies only when those data are required for therapy modification.
Anti-Bacterial Agents↗
Preliminary evidence of a synergistic alpha 1- and beta 1-adrenoceptor regulation of rat pineal hydroxyindole-O-methyltransferase.
The activity of serotonin N-acetyltransferase in the rat pineal is regulated through a synergistic action of norepinephrine on alpha 1- and beta 1-adrenoceptors. Rat pineal hydroxyindole-O-methyltransferase (HIOMT) activity is also responsive to the beta 1-adrenoceptor, while melatonin synthesis and indoleamine release in certain species is apparently under alpha 1-adrenoceptor control. The present study reports that the simultaneous administration of doxazosin (a selective alpha 1-adrenergic antagonist) and metoprolol (a selective beta 1-adrenergic antagonist) reduces peak HIOMT activity significantly more than either agent alone, indicating that rat pineal HIOMT is also subject to synergistic alpha 1- and beta 1-adrenergic regulation. The relationship between alpha 1-adrenoceptor stimulation, serotonin release, and HIOMT activity is considered, following the observation that nocturnal HIOMT activity is elevated in serotonin-depleted pineal glands.
Acetylserotonin O-Methyltransferase↗
Corneal wound healing after refractive surgery.
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Cornea↗
The importance of initial management in the treatment of severe infectious corneal ulcers.
PURPOSE: To identify factors that influence the outcome of patients with severe infectious corneal ulcers. METHOD: A retrospective review was performed of the hospital records of all such patients admitted to the Doheny Eye Hospital during a 30 month period. Outcome variables examined were change in visual acuity, duration of hospitalization, hospital charges, and percentage of patients who required penetrating keratoplasty. RESULTS: Sixty-two ulcers were included. An organism was identified and antibiotic sensitivities established in 52 patients (84%). Inpatient therapy involved a combination of fortified aminoglycoside and cephalosporin antibiotics in 39 patients (63%) and was found to be appropriate on the basis of sensitivity studies in 49 (94%) of 52 patients. Inappropriate initial treatment was related to increased hospital charge (P = 0.024) as well as increased risk of penetrating keratoplasty (P = 0.001). CONCLUSIONS: Appropriate initial therapy is most critical in the course of serious corneal ulcers, and aggressive, broad-spectrum antibiotic coverage is advocated.
Adolescent↗
Endophthalmitis and orbital cellulitis after radial keratotomy.
PURPOSE: To report the findings concerning three patients with endophthalmitis and one with panophthalmitis and orbital cellulitis radial keratotomy surgery. METHODS: One man referred with panophthalmitis and orbital cellulitis and three women referred with endophthalmitis were treated. RESULTS: After radial keratotomy surgery, during which no microperforation or macroperforation had been reported, a severe Pseudomonas panophthalmitis and orbital cellulitis developed in the man. All vision was lost in that eye. Staphylococcus epidermidis endophthalmitis developed in one woman, Streptococcus pneumoniae endophthalmitis in the second woman and Pseudomonas endophthalmitis in the third woman, after undergoing radial keratotomy procedures during which microperforations occurred. In the latter patient, bilateral simultaneous surgery was performed, but only one eye became infected. The latter two infections resulted in light perception and hand motion vision respectively. In three cases, an initial keratitis was located in the inferior cornea. CONCLUSIONS: Severe bacterial endophthalmitis can occur after radial keratotomy surgery, even in the absence of microperforation during the procedure. Any evidence of postoperative keratitis must be regarded seriously and treated aggressively. Despite use of this approach, the effect on final visual acuity can be devastating.
Adult↗
Stimulation of tyrosinase in human melanocytes by pro-opiomelanocortin-derived peptides.
Human melanocytes, maintained on bovine corneal endothelium-derived extracellular matrix for at least 4 days in the absence of phorbol 12-myristate 13-acetate (PMA) and cholera toxin (CT), displayed increased tyrosinase activity when exposed to several pro-opiomelanocortin-derived (POMC) peptides. Melanocytes from 9 of 14 donors showed significantly increased tyrosinase activity after treatment with adrenocorticotropic hormone (ACTH; mean increase 320 +/- 107 (S.E.M.)% of control, P < 0.005), while melanocytes from 8 of 13 donors increased tyrosinase in the presence of diacetyl-melanocyte stimulating hormone (di-MSH; mean increase 223 +/- 31 (S.E.M.)% of control, P < 0.005). Maximal increases in tyrosinase were seen after treatment with 10(-10) M ACTH and with 10(-6) M di-MSH. In two cell cultures which showed tyrosinase stimulation, melanin synthesis was similarly increased in the presence of added POMC peptides. PMA but not CT increased tyrosinase activity in melanocytes cultured under these conditions. In the presence of staurosporine, an inhibitor of protein kinase C (PKC), the magnitude of the increase in tyrosinase due to PMA, ACTH and di-MSH was significantly reduced. These results indicate that tyrosinase activity in melanocytes from most human donors, under appropriate conditions, is susceptible to the stimulatory effects of POMC peptides, that ACTH is considerably more potent than di-MSH in this test system and that in human cells the PKC pathway may be important in modulating melanogenesis.
Adrenocorticotropic Hormone↗
Changing indications for penetrating keratoplasty, 1989-1993.
The purpose of this study was to identify new trends in the changing indications for penetrating keratoplasty. We retrospectively reviewed the clinical and pathologic diagnoses of 1,104 corneal buttons that had been submitted to the Estelle Doheny Eye Pathology Laboratory, Los Angeles, during the 5-year period 1989-1993. The leading indications, in order of decreasing frequency, were pseudophakic corneal edema (24.8%), regrafts (21.3%), scarring with or without chronic inflammation (11.1%), keratoconus (7.1%), aphakic corneal edema (6.4%), and ulcerative conditions (5.8%). The incidence of pseudophakic corneal edema remained stable over the study period and was actually surpassed by regraft in the last year of the study. Although pseudophakic corneal edema remains the predominant indication for penetrating keratoplasty, our findings suggest that its occurrence rate has begun to level off.
Adolescent↗
Gazali-Temple syndrome.
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Abnormalities, Multiple↗
Effects of estrogens on human melanocytes in vitro.
Subjects with elevated serum estrogen concentrations, such as those who are pregnant or ingesting estrogen-containing contraceptive medication, may develop increased skin pigmentation. As little information is available on the mechanism(s) underlying this relationship, the in vitro effects of estrogens on melanocytes cultured from normal human skin were examined. Physiological concentrations of 17 beta-estradiol (10(-11) to 10(-9) M) significantly increased the activity of tyrosinase in melanocytes from 15 of 23 subjects. The observed increases ranged from 1.2- to 2.4-fold. Melanin synthesis, which correlated with tyrosinase activity (r = 0.98, P < 0.001) was increased to a similar extent. Melanin extrusion was also increased by 17 beta-estradiol (10(-9) M). The estrogens, estriol (10(-9) M) and estrone (10(-9) M) stimulated tyrosinase activity and melanin extrusion to a lesser extent than 17 beta-estradiol. The analogue 17 alpha-estradiol (10(-9) M) was shown to have effects on melanocyte tyrosinase activity and melanin extrusion that were equivalent to those of 17 beta-estradiol. The pure estrogen antagonist ICI 164384 (10(-6) M) also stimulated tyrosinase activity. Cycloheximide (50 micrograms/ml) inhibited 17 beta-estradiol-induced tyrosinase stimulation (P < 0.001). These results indicate that several aspects of melanocyte function respond directly to estrogenic stimulation. The equivalent effects of the 17 alpha-analogue and a "pure" anti-estrogen suggest that the 17 beta-estradiol response may be mediated through a non-classical mechanism which is similar to that described in other tissues of neural crest origin.
Cells, Cultured↗
A distinct diurnal rhythm in hydroxyindole-O-methyltransferase (HIOMT) activity in the male albino rat.
Pineal hydroxyindole-O-methyltransferase (HIOMT) has been reported to show a diurnal rhythm activity in the rat, although this is not fully confirmed. The present study reexamines this issue and reports a distinct diurnal rhythm in rat pineal HIOMT. Peak enzyme activity occurs 5 hr after the onset of darkness, followed by two lesser bursts of activity preceding each change in the photoperiod. The approximately 18-fold increase in methylating capacity at night represents the greatest variation in HIOMT activity thus far reported in the rat and may be attributed to the age, weight, and housing regimen of the animals used.
Acetylserotonin O-Methyltransferase↗
A longitudinal study of the relationship between intraocular and blood pressures.
The relationship between intraocular and systemic blood pressures was investigated in a prospective study of 572 middle-aged men. There was no consistent relationship between intraocular pressure at first visit and age. Subjects with an intraocular pressure greater than 20 mm Hg had a significantly higher systolic blood pressure than controls matched for age. An autoregressive model was used to examine the relationship between change in intraocular pressure and initial intraocular pressure, age, and blood pressure. When the authors compared data obtained 1 or 2 years apart, a change in intraocular pressure was positively correlated with a change in systolic blood pressure. Thus, the results of this study indicate that changes in intraocular pressure over time are associated with changes in systolic blood pressure and that intraocular pressure does not necessarily increase with age.
Adult↗
Evaluation of intraocular lens power calculation formulas in the triple procedure.
PURPOSE: To determine whether the choice of intraocular lens (IOL) power formula improves IOL power predictions and whether personalized constants within the IOL power formula are critical factors in improving refractive predictions after combined penetrating keratoplasty, cataract extraction, and IOL implantation. METHODS: Records of 46 patients who had the triple procedure between January 1988 and December 1992 were evaluated using the SRK II, SRK/T, Holladay, and Hoffer Q formulas to predict the postoperative spherical equivalent refractions for implanted lens power. Calculations were carried out with and without the use of personalized constants. The predictive accuracy of each formula was assessed by comparing the actual postoperative spherical equivalent refractive error with that predicted by the formulas. The predictive error and the distribution of predictive errors were used to assess predictive accuracy. RESULTS: There was no difference in the mean absolute predictive errors and the distribution of predictive errors for the four formulas evaluated (P > .05). The use of personalized formula constants significantly reduced the mean absolute predictive error for the SRK II, SRK/T, and Holladay formulas (P < .05) and approached significance for the Hoffer Q formula. CONCLUSION: The findings suggest that the choice of IOL power formula does not affect IOL power predictions in the corneal triple procedure; however, personalized constants within a formula appears to be a critical factor in improving postoperative refractive predictions.
Adult↗