Growth media and assay plate material can impact on the effectiveness of cationic biocides and antibiotics against different bacterial species.

The effectiveness of several cationic disinfectants as well as colistin and polymyxin B were assessed under different growth conditions against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa strains. These conditions included different media (MH1, MH2, TSB and LB) and plate material (polypropylene and polystyrene). Results showed that Minimum inhibitory and bactericidal concentrations (MIC/MBC) values of colistin and polymyxin B were significantly lower on polypropylene plates when compared to polystyrene plates regardless of media used. There were also differences in MIC/MBC values to certain biocides e.g. chlorhexidine and octenidine particularly for S. aureus and E. coli strains, with polypropylene again showing lower values. Other biocides appear to be mostly unaffected by plate type. Whether biocide efficacy was altered by media composition was organism dependent with S. aureus and E. coli more affected than P. aeruginosa. Lower MIC values were more commonly associated with MH2 media and higher MIC values with TSB media for both polypropylene and polystyrene plates, although there were exceptions. Results obtained for standard strains were, in general, indicative for other S. aureus, E. coli and P. aeruginosa strains tested. This study demonstrates the importance of media composition and plate material on biocide effectiveness and highlights the need for optimized disinfectant testing methods. SIGNIFICANCE AND IMPACT OF THE STUDY: There are an increasing number of reports of bacterial strains that are multi-drug resistant. The use of biocides as part of infection control is crucial in helping to combat the spread of these particular strains. Unlike for antibiotics, there are few standardized measuring techniques to understand if an isolate has become more resistant to biocides. This study demonstrates the importance of media composition and plate material on variation and reporting of susceptibility of several bacterial species to specific cationic biocides. It is a useful comparison study to highlight the need to standardize biocide susceptibility testing.

Automation in high-content flow cytometry screening.

High-content flow cytometric screening (FC-HCS) is a 21st Century technology that combines robotic fluid handling, flow cytometric instrumentation, and bioinformatics software, so that relatively large numbers of flow cytometric samples can be processed and analysed in a short period of time. We revisit a recent application of FC-HCS to the problem of cellular signature definition for acute graft-versus-host-disease. Our focus is on automation of the data processing steps using recent advances in statistical methodology. We demonstrate that effective results, on par with those obtained via manual processing, can be achieved using our automatic techniques. Such automation of FC-HCS has the potential to drastically improve diagnosis and biomarker identification.

Loss of mammary epithelial prolactin receptor delays tumor formation by reducing cell proliferation in low-grade preinvasive lesions.

Top quartile serum prolactin levels confer a twofold increase in the relative risk of developing breast cancer. Prolactin exerts this effect at an ill defined point in the carcinogenic process, via mechanisms involving direct action via prolactin receptors within mammary epithelium and/or indirect action through regulation of other hormones such as estrogen and progesterone. We have addressed these questions by examining mammary carcinogenesis in transplants of mouse mammary epithelium expressing the SV40T oncogene, with or without the prolactin receptor, using host animals with a normal endocrine system. In prolactin receptor knockout transplants the area of neoplasia was significantly smaller (7 versus 17%; P < 0.001 at 22 weeks and 7 versus 14%; P = 0.009 at 32 weeks). Low-grade neoplastic lesions displayed reduced BrdU incorporation rate (11.3 versus 17% P = 0.003) but no change in apoptosis rate. Tumor latency increased (289 days versus 236 days, P < 0.001). Tumor frequency, growth rate, morphology, cell proliferation and apoptosis were not altered. Thus, prolactin acts directly on the mammary epithelial cells to increase cell proliferation in preinvasive lesions, resulting in more neoplasia and acceleration of the transition to invasive carcinoma. Targeting of mammary prolactin signaling thus provides a strategy to prevent the early progression of neoplasia to invasive carcinoma.

Simple fitting of subject-specific curves for longitudinal data.

We present a simple semiparametric model for fitting subject-specific curves for longitudinal data. Individual curves are modelled as penalized splines with random coefficients. This model has a mixed model representation, and it is easily implemented in standard statistical software. We conduct an analysis of the long-term effect of radiation therapy on the height of children suffering from acute lymphoblastic leukaemia using penalized splines in the framework of semiparametric mixed effects models. The analysis revealed significant differences between therapies and showed that the growth rate of girls in the study cannot be fully explained by the group-average curve and that individual curves are necessary to reflect the individual response to treatment. We also show how to implement these models in S-PLUS and R in the appendix.

A local likelihood proportional hazards model for interval censored data.

We discuss the use of local likelihood methods to fit proportional hazards regression models to right and interval censored data. The assumed model allows for an arbitrary, smoothed baseline hazard on which a vector of covariates operates in a proportional manner, and thus produces an interpretable baseline hazard function along with estimates of global covariate effects. For estimation, we extend the modified EM algorithm suggested by Betensky, Lindsey, Ryan and Wand. We illustrate the method with data on times to deterioration of breast cosmeses and HIV-1 infection rates among haemophiliacs.

Latanoprost and cystoid macular edema in high-risk aphakic or pseudophakic eyes.

PURPOSE: To determine the magnitude of the association between latanoprost use and cystoid macular edema (CME) in high-risk aphakic or pseudophakic eyes. SETTING: Single referral glaucoma practice. METHODS: In a referral glaucoma practice, 40 consecutive patients with glaucoma uncontrolled on maximally tolerated medications without latanoprost were studied. Seven eyes were aphakic, and 33 eyes were pseudophakic. All eyes had an absent or open posterior capsule, and 29 eyes had 1 or more additional risk factors for developing CME. Latanoprost 0.005%, 1 drop at bedtime, was added to the patients' current regimen. Patients were instructed to check their vision in the treated eye daily at home and to report any perceived decrease promptly. Patients without a change in vision or other side effects were reexamined 1 month after initiating latanoprost and every 3 months thereafter. If there was a greater than 1 line decrease in visual acuity, a retinal evaluation and fundus fluorescein angiography (FFA) were performed by a retina specialist. RESULTS: Two eyes had to discontinue latanoprost because of side effects before the 1 month visit. They were excluded from the analysis. At the 1 month follow-up, the mean intraocular pressure was 18.2 mm Hg +/- 6.5 (SD), a decrease from the pretreatment mean of 21.5 +/- 5.7 mm Hg. The visual acuity was within 1 line of baseline in 36 eyes and decreased by 2 lines in 2 eyes. In these 2 eyes, symptomatic CME was documented by FFA. The CME clinically resolved, with visual acuity returning to baseline after the latanoprost was discontinued and a nonsteroidal antiinflammatory drug started. There were no additional cases of CME after a mean follow-up of 5.7 months. CONCLUSION: Approximately 5% of high-risk eyes treated with latanoprost developed clinically symptomatic and angiographically documented CME. The temporal relationship between initiation of treatment and the decreased vision in our 2 cases suggests but does not establish a causal relationship between CME and latanoprost. With appropriate informed consent and attentive follow-up, clinicians should not be deterred from using this important glaucoma medication.

Polymorphism of the beta(2)-adrenergic receptor gene and desensitization in human airway smooth muscle.

We examined the influence of two common polymorphic forms of the beta(2)-adrenergic receptor (beta(2)AR): the Gly16 and Glu27 alleles, on acute and long-term beta(2)AR desensitization in human airway smooth muscle (HASM) cells. In cells from 15 individuals, considered without respect to genotype, pretreatment with Isoproterenol (ISO) at 10(-7) M for 1 h or 24 h caused approximately 25% and 64% decreases in the ability of subsequent ISO (10(-6) M) stimulation to reduce HASM cell stiffness as measured by magnetic twisting cytometry. Similar results were obtained with ISO-induced cyclic adenosine monophosphate (cAMP) as the outcome indicator. Data were then stratified post hoc by genotype. Cells containing at least one Glu27 allele (equivalent to presence of the Gly16Glu27 haplotype) showed significantly greater acute desensitization than did cells with no Glu27 allele, whether ISO-induced cell stiffness (34% versus 19%, p < 0.03) or cAMP formation (58% versus 11%, p < 0.02) was measured. Likewise, cells with any Glu27 allele showed greater long-term desensitization of cell stiffness and cAMP formation responses than did cells without the Glu27 allele. The distribution of genotypes limited direct conclusions about the influence of the Gly16 allele. However, presence of the Gly16Gln27 haplotype was associated with less acute and long-term desensitization of ISO-induced cAMP formation than was seen in cells without the Gly16Gln27 haplotype (14% versus 47%, p < 0.09 for short-term desensitization; 32% versus 84%, p < 0.01 for long-term desensitization), suggesting that the influence of Glu27 is not through its association with Gly16. The Glu27 allele was in strong linkage disequilibrium with the Arg19 allele, a polymorphic form of the beta(2)AR upstream peptide of the 5'-leader cistron of the beta(2)AR, and this polymorphism in the beta(2)AR 5'-flanking region may explain the effects of the Glu27 allele. Cells with any Arg19 allele showed significantly greater acute and long-term desensitization of ISO-induced cAMP formation than did cells without the Arg19 allele (54% versus 2%, p < 0.01 for short-term desensitization; 73% versus 35%, p < 0.05 for long-term desensitization). Similar results were obtained for ISO-induced changes in cell stiffness. Thus, the presence of the Glu27 allele is associated with increased acute and long-term desensitization in HASM.

Long-term effect of Nd:YAG laser posterior capsulotomy on intraocular pressure.

OBJECTIVE: To study the long-term effect of Nd:YAG capsulotomy on intraocular pressure (IOP). METHODS: We reviewed the records of patients with bilateral pseudophakia who received Nd:YAG capsulotomy in only 1 eye. Using the Wilcoxon rank sum test, we compared the mean change in IOP in eyes before and after capsulotomy with that of the noncapsulotomy eyes at corresponding time intervals. Using multiple regression tests, we analyzed the factors significantly associated with postcapsulotomy long-term IOP increases. RESULTS: The study included 100 patients who were followed up for a median of 1.5 years after capsulotomy. The mean +/- SD age of the study group was 76+/-7 years, and 37 patients had glaucoma. The changes in IOP in the eyes treated with capsulotomy were significantly higher than those in noncapsulotomy eyes at each time interval following capsulotomy. The long-term IOP increase was significantly associated with the IOP increase measured 1 hour after the capsulotomy (P =. 001). Patients with glaucoma were more likely to require long-term additional glaucoma medication than were nonglaucoma patients to require initial glaucoma therapy after the capsulotomy (P =.002). CONCLUSION: After Nd:YAG capsulotomy, long-term IOP is often elevated above precapsulotomy baselines, especially in glaucoma patients or patients who experience a significant IOP increase within hours after the capsulotomy.

Visually significant cystoid macular edema in pseudophakic and aphakic patients with glaucoma receiving latanoprost.

PURPOSE: To investigate the incidence of visually significant cystoid macular edema associated with the use of latanoprost in patients with glaucoma after cataract surgery. PATIENTS AND METHODS: This is a multicenter, retrospective study of 185 patients, of whom 173 were pseudophakic (212 eyes) and 12 were aphakic (13 eyes), who were treated for glaucoma with latanoprost 0.005%. The posterior lens capsule was intact in 125 eyes, open or absent as a result of surgery in 25 eyes, and status-post-yttrium-aluminum-garnet capsulotomy in 75 eyes. Visual acuity was documented before and after initiating latanoprost therapy, and patients with a reduction of two or more lines on the Snellen chart were examined by fluorescein angiography for cystoid macular edema. RESULTS: Visual reduction was documented in four (2.16%) patients. Three of the four patients had cystoid macular edema, and the fourth was thought to have lost a central island of vision from glaucoma. The three patients with cystoid macular edema all had ruptured posterior capsules, requiring anterior vitrectomy, and one had a previous episode of cystoid macular edema 3 years before starting latanoprost therapy. CONCLUSION: These findings suggest that visually significant cystoid macular edema associated with latanoprost therapy in pseudophakic or aphakic patients is uncommon. If there is a cause-and-effect relationship between latanoprost therapy and clinically significant cystoid macular edema, the incidence appears to be low.

Negative binomial additive models.

The generalized additive model is extended to handle negative binomial responses. The extension is complicated by the fact that the negative binomial distribution has two parameters and is not in the exponential family. The methodology is applied to data involving DNA adduct counts and smoking variables among ex-smokers with lung cancer. A more detailed investigation is made of the parametric relationship between the number of adducts and years since quitting while retaining a smooth relationship between adducts and the other covariates.

Latanoprost in glaucoma associated with Sturge-Weber syndrome: benefits and side-effects.

PURPOSE: This study was conducted to evaluate the ocular hypotensive efficacy, safety, and side effects of latanoprost 0.005% administered as adjunctive therapy in patients with Sturge-Weber syndrome (SWS) and glaucoma. METHODS: Commercially available latanoprost 0.005% was added as a single drop once daily to other antiglaucoma medications. Intraocular pressure (IOP) was measured at 1, 3, and 6 months of treatment. A successful response was defined as a reduction of at least 20% in IOP at the final follow-up evaluation without additional medical or surgical therapy and no adverse events related to latanoprost. RESULTS: 18 eyes of 18 patients with SWS and glaucoma were enrolled from 9 clinical centers. Mean baseline IOP was 28.4 +/- 7.1 mmHg (range, 17-42 mmHg). Using Kaplan-Meier analysis, a successful response to latanoprost was observed in 3 of 18 (16.7%) patients at the 6-month interval. Seven (38.9%) patients required surgery; three (16.7%) patients required additional medical therapy, seven (38.9%) patients had no change in therapy. One (5.6%) patient discontinued latanoprost treatment because of intolerable conjunctival hyperemia. Two successfully treated patients had significantly greater episcleral vessel engorgement after initiation of latanoprost therapy. CONCLUSION: Patients with SWS and glaucoma respond poorly to adjunctive latanoprost therapy and often require additional medical or surgical intervention. Increased episcleral vascular engorgement might result in greater operative risks should filtration surgery become necessary in these patients.

Local EM estimation of the hazard function for interval-censored data.

We propose a smooth hazard estimator for interval-censored survival data using the method of local likelihood. The model is fit using a local EM algorithm. The estimator is more descriptive than traditional empirical estimates in regions of concentrated information and takes on a parametric flavor in regions of sparse information. We derive two different standard error estimates for the smooth curve, one based on asymptotic theory and the other on the bootstrap. We illustrate the local EM method for times to breast cosmesis deterioration (Finkelstein, 1986, Biometrics 42, 845-854) and for times to HIV-1 infection for individuals with hemophilia (Kroner et al., 1994, Journal of AIDS 7, 279-286). Our hazard estimates for each of these data sets show interesting structures that would not be found using a standard parametric hazard model or empirical survivorship estimates.

Supraciliary effusions and ciliary body thickening after scleral buckling procedures.

PURPOSE: The purpose of the study was to use ultrasound biomicroscopy to identify and quantity changes in anterior segment parameters after scleral buckling procedures. METHODS: Ultrasound biomicroscopy was used to examine 15 patients with retinal detachment within 1 week before and after surgery. Quantitative measurements were performed of anterior chamber depth, supraciliary effusion depth, ciliary body thickness, and angle opening. RESULTS: Supraciliary fluid was present after surgery in 12 patients (80%). Average supraciliary fluid depth was 0.16 +/- 0.13 mm. Ciliary body thickness measurements at a point 2-mm posterior to the scleral spur increased after surgery in all patients an average of 0.15 +/- 0.10 mm. There was a strong correlation between ciliary fluid levels and change in ciliary body thickness (r = 0.742, P < 0.01). Anterior chamber depth decreased after surgery in 14 patients (93%). A decrease of angle opening of greater than 5 degrees was noted in 11 patients (73%). In all of these 11 patients, the ciliary body and iris root were considered to be rotated anteriorly. Six (55%) of 11 of these patients showed anterior bowing of the iris, indicating pupillary block. Complete angle closure occurred over one to three quadrants in three patients, but none of these patients had complete angle closure or glaucoma. CONCLUSIONS: Supraciliary effusions and ciliary body thickening are common after scleral buckling procedures and can produce conditions conducive to angle closure. Angle narrowing occurs through a combination of direct anterior iris rotation and induced pupillary block.

Combined phacoemulsification, intraocular lens implant, and trabeculectomy with intraoperative mitomycin-C: comparison between 3.2- and 6.0-mm incisions.

PURPOSE: To compare surgical results between 3.2- and 6.0-mm incisions in combined phacoemulsification, intraocular lens implant, and trabeculectomy with intraoperative mitomycin-C. METHODS: Fifty-seven consecutive eyes of 45 patients in a referral practice underwent combined phacoemulsification, intraocular lens implant, and trabeculectomy with intraoperative mitomycin-C. The first 24 eyes had a 6.0-mm incision and the next 33 eyes had a 3.2-mm incision; the procedures were otherwise identical. The postoperative intraocular pressures, number of antiglaucoma medications, presence of filtration blebs, visual acuity, and complications at 1 day, 1 week, 1 month, and 1 year were subjected to multivariate analysis. RESULTS: There were no statistical differences in the intraocular pressure control, number of antiglaucoma medications, or presence of filtration bleb between the two groups at any of the postoperative visits. Visual acuity was significantly better (p = 0.02) for the 3.2-mm incision group throughout the evaluation period. CONCLUSIONS: Both large- and small-incision phacoemulsification, intraocular lens implant, and trabeculectomy with intraoperative Mitomycin-C provide good intermediate range (1 year) postoperative IOP in eyes with coexisting cataract and glaucoma. In addition, small-incision surgery results in earlier and better visual rehabilitation than large-incision surgery.

Antibiotic prophylaxis in eyes with filtration blebs: survey of glaucoma specialists, microbiological study, and recommendations.

PURPOSE: Bleb-related endophthalmitis is a major late complication of filtration surgery. The purpose of this study was to determine the ophthalmic practic patterns regarding long-term antibiotic prophlaxis in eyes with filtration blebs, and the effect of long-term antibiotic usage on conjunctival bacterial flora. METHODS: A mail survey of members of the American Glaucoma Society (AGS) was undertaken. In addition. 41 patients who had filtation surgery and received long-term topical antibiotic therapy in one eye only had conjunctival cultures performed in both eyes. RESULTS: Of the responding members of the AGS, only 6% routinely prescribed long-term antibiotic prophylaxis, 28% prescribed therapy in selected cases only, and 66% did not employ antibiotic prophylaxis. Although more physicians than not had observed endophthalmitis in patients not receiving antibiotic therapy, it was evident that antibiotic prophylaxis did not guarantee that endophthalmitis would not develop in a filtered eye. A total of 49 organisms were isolated from the conjunctiva of eyes receiving antibiotic prophylaxis and 52 organisms were isolated from eyes not receiving antibiotic prophylaxis. There was no statistically significant difference in the types of organisms isolated. CONCLUSION: Long-term antibiotic prophylaxis does not appear to be a common practice among glaucoma specialists in this country, and it cannot be depended upon as a fail-safe method to prevent bleb-related endophthalmitis. Furthermore, long-term antibiotic usage does not appear to alter the conjunctival flora. Of paramount importance are early detection and treatment of bleb-related infections. Critical in this regard is patient education. Recommendations to minimize the development of endophthalmitis in filtered eyes are reviewed.

Intraoperative intracameral viscoelastic agent in the prevention of postfiltration flat anterior chamber.

A flat anterior chamber after filtration surgery is a serious complication. Intraoperative hypotony with resultant suprachoroidal effusion may be the initial step in the cascade of events leading to this condition. The choroid has a natural elasticity that results in negative pressure in the potential suprachoroidal space when the eye is hypotonous during surgery. To prevent the development of intraoperative hypotony, an intracameral viscoelastic agent (sodium hyaluronate) was used before the filtration surgery. With this technique, only 1 of 60 eyes (1.7%) developed postoperative flat anterior chamber compared with 10 of 60 eyes (16.7%) operated on without the use of an intraoperative intracameral viscoelastic agent. Further evaluation of this technique appears warranted.