bluuebunny/crossref_metadata_2025 huggingface dataset:
Fundamentals of cataract development
Authors: WEGENER A
Published: September 2009

The lens is a highly specialized tissue in the vertebrate eye, whose growth characteristics and metabolic turn‐over are designed for longevity in respect to its optical function. It grows throughout life and does neither shed any of its cells, nor excrete any degraded proteins. The lens manages to maintain an optical and a biochemical gradient based on the high protein content (crystallins) and slow metabolic turn‐over in the superficial fibre cells. It is well equipped with anti‐oxidative defence mechanisms, can seal off groups of damaged fibre cells and changes its transmission properties during ageing. The 3 main ageing characteristics in the lens are a tissue layer specific increase in light scattering, a yellowish discoloration of the proteins and a loss of accommodative capacity. Cataract development can be triggered by a wide selection of factors including genetic predisposition, certain diseases, optical and ionizing radiation, chemical compounds, drugs, nutritional and environmental factors, as well as trauma. Patho‐physiological mechanisms involved are DNA damage in epithelial cells, protein glycosylation and aggregation and molecular cross linking in lens fibre cells, metabolic breakdown of selected groups of fibre cells or of a whole layer, protein degradation and finally globular degeneration and liquefaction. Ageing in this context is the time line which allows an increasing number of noxious factors to interact in the lens at decreasing metabolic capacities. While the sensitivity of the lens to oxidative damage increases during ageing, its sensitivity to low dose ionizing radiation decreases. The function of molecular receptors for acetylcholine, steroids, the sigma receptor and other receptors found in the lens is still unknown, but might explain the specific reaction to certain drugs.
The use of animal models for the evaluation of ocular antiviral agents
Authors: ROMANOWSKI EG
Published: September 2009

Animal models have been used extensively in the evaluation and development of topical ocular antiviral agents. Rabbit ocular models have proven predictive of the clinical efficacy of topical antiviral agents for HSV‐1 epithelial keratitis and in clinical trials for adenoviral ocular infections. The current presentation will discuss the limitations of these models and present data on potential new topical antiviral agents, focusing primarily on antivirals for adenoviral ocular infections.
The treatment of uveal melanoma with iodine plaque brachytherapy
Authors: KIVELÄ T
Published: September 2009

Purpose To provide an overview of managing uveal melanoma (UM) with iodine brachytherapy (IBT).

Methods Personal experience of the author in using IBT since 1990.

Results IBT is an effective option for managing a UM of any size, although it is mostly used for medium‐sized tumours, preference being given to ruthenium brachytherapy (RBT) when the tumour is <5‐6 mm thick and to transscleral local resection when thickness is >6 mm, especially when vision is good. IBT is also a safe alternative to enucleation of large UM >10 mm in thickness if the patient is keen to preserve the eye and motivated to accept eventual complications. The plaque is positioned over the UM with a 1‐2 mm safety margin when using a collimated/rimmed plaque. Because of stray radiation, a safety margin is not mandatory when the plaque is non‐collimated/non‐rimmed. Otherwise, surgical technique does not differ from RBT. An advantage of IBT is that the radioactive seeds are separate from the plaque, allowing economical use of plaques of many different sizes and shapes and individual positioning of the seeds in a conformal way. A disadvantage is a short half‐life; the seeds need to be changed every 6 months. The dose the author uses is 80 Gy to tumour apex, which is reduced on an individual basis to 60‐70 Gy when the UM is very thick. Local tumour control rate is 90% and, paradoxically, not worse for large UM as compared to smaller ones. There are no unequivocal safety distances for avoiding radiation cataract, maculopathy and optic neuropathy, which are more or less frequent depending on the size and location of the UM.

Conclusion IBT achieves good local tumour control of UM of all sizes, but preservation of vision is decidedly less frequent than after RBT, which is always given preference.
Tibial Bone KPro technique and long term results
Authors: TEMPRANO J
Published: September 2009

The operation is performed in three stages. The first stage consists in preparing the eye to receive and maintain the keratoprosthesis. For this purpose the anterior surface of the eye is cleaned and regularized, eliminating fibrous tissue and the entire epithelium. Subsequently we obtain a 2 x 3 cm graft of buccal mucosa from the inferior lip comprising the entire mucosal and submucosal thickness. The graft is sutured to cover the anterior pole of the eye to promote revitalization. The second stage consists in preparing the keratoprosthesis. A 10 mm disk of tibial bone from the superior part of the medial face of the tibia is obtained using a crown drill. The posterior part of the piece of bone obtained is then cut with a chisel to obtain a thickness of 3 mm. Subsequently the obtained disk of bone is cleaned and a central opening of 3.5 mm is performed to introduce in this opening a PMMA optic cylinder, 9 mm in length, 3.5 mm in diameter in its narrow portion, 4 mm in the wider portion. Fixation is achieved with cyanoacrylate. This is left to dry and then it is introduced into a palpebral pocket of the inferior lid of the patient. The pocket is closed with sutures and the piece is left in place for three months. For the third stage we remove the keratoprosthesis device from the palpebral pocket and if it is found to be in perfect conditions we dissect the buccal mucous membrane which is covering the cornea and perform a central window with a 4.5 mm trephine to remove the transparent or cataractous lens and perform a total iridectomy. The posterior portion of the optic cylinder is introduced into the anterior chamber. The prosthesis is sutured to the anterior pole of the eye with non‐absorbible sutures. Finally the buccal mucosa is replaced, covering the entire area. One point of blepharorraphy is applied. Long term results. We started to use this technique in 1988 and after 21 years of experience we have 80% of anatomically perfect results. In 20 % of the cases the prosthesis extruded due to total or partial resorption of the bone. It has to be emphasized that these were cases without any other possibility of treatment. We did 143 cases during these years. The longest follow‐up of a prosthesis “in situ” is 19 years. The earliest extrusion was after one year. The complications are the same as for OOKP (glaucoma, retinal detachment, vitritis, extrusion) The functional results depend on the conditions of the retina and the optic nerve. There were many cases with 20/20 vision. The mean value of retention of the prosthesis is 15 years.
Management of oculoplastic problems in the OOKP eye
Authors: GOMAA A , MORRIS S , BRITTAIN P , HEROLD J , THORP S , LIU C
Published: September 2009

OOKP surgery (either stage 1 or 2) can result in complex oculoplastic complications. The majority of these are mucous membrane graft‐related, including graft thinning, ulceration and infection or overgrowth onto the anterior optical cylinder. However, lid malposition, forniceal shortening and widening of the palpebral aperture may also occur. Appropriate timely surgical intervention of these is crucial to protect the underlying OOKP lamina. In addition, correcting over‐exposure of the globe aids in improved comfort for the patient. Adjustments of the lid and forniceal abnormalities can enhance comfort, cosmesis and prosthetic shell stability. Retrospective case note analysis of all patients treated 1996 – 2009 at the Sussex Eye Hospital, Brighton, UK, was performed. This study reports the prevalence and type of oculoplastic complications found and describes the surgical management for each.
Dealing with complications of MOOKP: VR
Authors: HUGHES E
Published: September 2009

Abstract not provided
Occludin changes in retinal vessels after experimental vein thrombosis in rats
Authors: TSILIMBARIS M , TSOKA P , BOCHATON‐PIALLAT ML , CHRISTODOULAKIS E , GILODI N , POURNARAS CJ
Published: September 2009

Purpose To evaluate the changes in occludin after experimental vein thrombosis in rats. Occludin is an integral plasma‐membrane protein located specifically at tight junctions.

Methods The retinal veins of 24 pigmented rats were occluded by means of fluorescein augmented laser photocoagulation. The animals were sacrificed after 4 and 24 hours, their eyes were enucleated and retinas were harvested. Retina whole mounts were prepared for indirect immunohistochemistry using an anti‐occludin primary antibody and were examined under confocal microscope. The retinas of 4 normal animals were used as controls.

Results The characterisitc reticular fluorescense of occludin was detected along vascular branches in a three‐dimentional manner with the help of the confocal microscope. Alterations in occludin distribution could be detected along thrombosed veins, peripheraly to the site of thrombosis. These alterations included irregular linear fluorescence and increased spaces of absent fluorescence in major vein branches compared to controls. The alterations in the superficial and deep vascular plexuses were less prominent including a reduced fluorescence of occludin. No changes were detected at the arteriolar walls. All findings were more prominent at 24 hours.

Conclusion Blood‐retina barrier impairment is expressed with morphological alterations of occludine distribution 24 hours after experimentally induced vein thrombosis
Structural consequences after intravitreal bevacizumab injection in a retinopathy of prematurity mouse model
Authors: AKKOYUN I , YILMAZ G , OTO S , KARABAY G , HABERAL N , ERKANLI L , BACANLI D , AKOVA A Y
Published: September 2009

Purpose To evaluate the effect of different bevacizumab concentrations on retinal endothelial cell proliferation and retinal structures in a retinopathy of prematurity (ROP) mouse‐model

Methods A total of 35 of C57BL/J6 mice were exposed to 75±2% oxygen from postnatal day 7 to postnatal day 12. On day 12, 10 mice (group‐C) were injected with 2.5μg intravitreal bevacizumab (IVB), 11 mice (group‐D) with 1.25μg IVB, and 14 mice (group‐E) with 0.625μg IVB in one eye. The contralateral eyes were injected with isotonic saline (control group=group‐B). Four nonexposed mice served as negative controls (group‐A). Neovascularization was quantified by counting the endothelial cell nuclei on the vitreal side of the inner limiting membrane of the retina. Histologic and ultrastructural changes were examined by light and electron microscopy.

Results The endothelial cell count per histological section was lower in group C (p<0.0001), D (p<0.0001) and E (p<0.0001) compared with the control group‐B. Histologic evaluation showed no retinal toxicity in any group. Electron microscopy revealed hyperoxia induced mitochondrial dysmorphology in group‐B and mitochondrial dysmorphology displayed dose dependent increase in IVB injected eyes.

Conclusion Bevacizumab suppresses endothelial cell proliferation in a ROP‐mouse‐model. In addition to hyperoxia induced vulnerability of C57BL/J6 retina, morphological findings implicate further ultrastructural vulnerability due to bevacizumab.
Circulating bone marrow‐derived endothelial precursor cells contribute to neovascularization in diabetic epiretinal membranes
Authors: ABU EL ASRAR A , STRUYF S , VERBEKE H , VAN DAMME J , GEBOES K
Published: September 2009

Purpose Role of vasculogenesis, recruitment and differentiation of circulating bone marrow‐derived endothelial precursor cells into mature endothelium, in proliferative diabetic retinopathy (PDR) remains undefined. We investigated the presence of bone marrow‐derived endothelial precursor cells and the expression of the chemotactic pathway SDF‐1/CXCL12?CXCR4 in PDR epiretinal membranes.

Methods Membranes from 8 patients with active PDR and 9 patients with inactive PDR were studied by immunohistochemistry using antibodies against CD133, vascular endothelial growth factor receptor‐2 (VEGFR‐2), CD14, SDF‐1 and CXCR4.

Results Blood vessels expressed CD133, VEGFR‐2, CD14, SDF‐1 and CXCR4 in 10, 10, 10, 7 and 7 out of 17 membranes, respectively. There were significant correlations between number of blood vessels expressing CD34 and number of blood vessels expressing CD133 (rs=0.646; p=0.005), VEGFR‐2 (rs=0.704; p=0.002), CD14 (rs=0.564; p=0.018), and SDF‐1 (rs=0.577; p=0.015). Stromal cells in close association with blood vessels expressed CD133, VEGFR‐2, CD14, and CXCR4 in 10, 12, 13, and 14 membranes, respectively. Number of blood vessels expressing CD133 (p=0.013), VEGFR‐2 (p=0.005), CD14 (p=0.008) and SDF‐1 (p=0.005), and stromal cells expressing CD133 (p=0.003), VEGFR‐2 (p=0.013) and CD14 (p=0.002) was significantly higher in active membranes than in inactive membranes.

Conclusion Bone marrow‐derived CD133+ endothelial progenitor cells and CD14+ monocytes may contribute to vasculogenesis in PDR.
Experience with adalimumab for the treatment of non‐infectious uveitis
Authors: DOBNER B
Published: September 2009

Purpose Objective: The aim of this study has been to assess the efficacy of adalimumab (ADA) in patients with uveitis in 3 centers.

Methods In a retrospective study we identified patients from all instituitions´databases, who were treated with ADA in an average period of 20.16 months (range 1.3‐45 months). The 5 criteria that the efficacy of ADA had been judged on are: reduction of macular edema by OCT, visual acuity, anterior chamber cells, reduction of flares and a reduction of prednisone dose during the treatment. At least one of the criteria had to be improved and none of the others worsened to declare treatment as effective.

Results Of the 61 patients who were treated with ADA, 38 were treated for uveitis and systemic disease, 3 primarily for active systemic disease and 20 primarily for active uveitis. 15 patients had been treated before with etanercept and 11 with infliximab, with insufficient response. We saw an improvement in 49 out of these 61 patients (80,3%) in 1 or more criteria and worsening in none, 5 patients did not meet improvement criteria and were given additional or alternative treatment, three of them mainly due to activity of systemic disease. 14 out of 49 (28,6%)Patients showed an Improvement in every criteria, the other patients showed increasing in at least one criteria, the other criterias remained stable. At the last follow‐up there were 50 (81,9%) patients still on ADA treatment. 11 patients stopped ADA treatment for different reasons (inefficacy, active systemic disease, pregnancy etc.).

Conclusion In this retrospective study we judged that the treatment with ADA in patients with uveitis with or without systemic disease was effective in 80,3%. Clinical trials are warrented

Commercial interest
Topical levofloxacin 1.5% Is effective in reducing levofloxacin‐resistant MRSA and FQ‐resistant pseudomonas aeruginosa in keratitis models
Authors: KOWALSKI RP , ROMANOWSKI EG , MAH FS , SHANKS RMQ , GORDON YJ
Published: September 2009

Purpose We compared topical levofloxacin 1.5% (LEV) to standard therapies in reducing levofloxacin‐resistant Staphylococcus aureus (MRSA) and FQ‐resistant Pseudomonas aeruginosa (PA) in keratitis models.

Methods Both corneas of 32 NZW rabbits were intrastromally injected with 1000 CFU of MRSA (LV MIC=32 μg/ml; van MIC=2 μg/ml). After 4 hours (onset), 8 rabbits were sacrificed and the corneas were homogenized for colony counts. 24 rabbits were divided into 3 topical treatment groups: 1) LEV, 2) vancomycin 5%, and 3) saline. Treatment consisted of drops every 15 minutes/5 hours (21 drops). One hour after treatment, the rabbits were sacrificed and the corneas were homogenized for colony counts. Similar to MRSA, 32 NZW rabbits were intrastromally injected with 1000 CFU of PA (LV MIC=32 μg/ml, tob=0.75 μg/ml). After 16 hours (onset), 8 rabbits were sacrificed and the corneas were homogenized for colony counts. 24 rabbits were divided into 3 topical treatment groups: 1) LEV, 2) tobramycin 1.4%, and 3) saline. Treatment consisted of drops every 15 minutes/1 hour and every 30 minutes/7 hours (19 drops). One hour after treatment, the rabbits were sacrificed and the corneas were homogenized for colony counts. The CFU data were analyzed non‐parametrically.

Results LEV significantly reduced more MRSA than vancomycin 5%, and both significantly reduced more MRSA than the onset and saline control (p<0.05). LEV was as effective as tobramycin 1.4% in reducing PA, and both significantly reduced more PA than the onset and saline control (p<0.05).

Conclusion LEV was more effective for reducing MRSA and as effective for reducing PA as standard therapies in rabbit keratitis models.

Commercial interest
Local resection of end‐stage choroidal melanoma
Authors: DAMATO B
Published: September 2009

Abstract not provided
Some questions of immune response to retinal S‐antigen and development of myopia's complications
Authors: LAZUK AV , SLEPOVA OS
Published: September 2009

Purpose To estimate reliability of the prognosis of an unfavorable current of myopia on the basis of estimation immune response to a retinal S‐antigen in tears and blood sera

Methods We have studied an autoimmune response to S‐Antigen (48kDa) in tears and in blood sera (ELISA) in 113 patients with progressive and complicated myopia with a follow‐up study of 44 patients (average age 11 ± 1,5 y.o.) without (15) and with (29) different forms of peripheral vitreochorioretinal dystrophies (PVCRD)during 11 years.

Results The long‐term study shows, that prognosis of complication’s development was right in 83,4%. Most unfavorable signs of preclinic myopia complications are a deficient of S‐antibodies (s‐ab)in tears and blood sera ‐ the prognosis for development of retinal disorders and/or fast and long myopia progression was confirmed at 51,6% of patients. High level of s‐ab in blood sera and deficient of s‐ab in tears was also the sign of development of PVCRD (the prognosis was confirmed at 22,6%). Occurrence or aggravation of changes at the retina began between 6 month and 1,5 years after revealing of the specified changes that testifies to authentically early prognosis in the beginnings of development of preclinical changes in myopic eye. Patients with tuberculin sensibilisation and deficient of S‐antibodies in blood sera (observation’s time 14 years) had worse retinal disturbances.

Conclusion This data allows to use s‐ab level for prognosis of the development of myopia's complication.It is very important to know that tuberculin vaccinations may be a risk‐factor in development of myopia complications and autoimmune uveitis. It opens up new vistas for the immunocorrective methods in the system of the treatment of progressive and complicated myopia.
Evaluation of choroidal blood flow after treatment of retinal diseases
Authors: CHIQUET C , GEISER MH
Published: September 2009

Purpose this review aims to summarize studies which assessed the effect of treatment on choroidal blood flow.

Methods this presentation will focus on studies using the laser Doppler flowmeter for the analysis of choroidal blood flow parameters (velocity, volume and flow) before and after treatment. Therapies have been assessed in different ocular disease, such as age‐related macular degeneration (laser photocoagulation therapy, photodynamic therapy, transpupillary thermotherapy, sildenafil citrate, niacin, pentoxifylline), diabetes mellitus (panretinal photocoagulation, intravenous C‐peptide infusion), retinal vein occlusions (isovolemic hemodilution), macular edema (diclofenac), inflammation (corticosteroid), retinal detachment (surgery) or glaucoma (nimodipine, endothelin receptor antagonist, bimatoprost, timolol, trabeculectomy).

Results this paper will give insight to the effects of laser treatment (laser photocoagulation, photodynamic therapy), surgery (scleral buckling, trabeculectomy, ocular anesthesia) or systemic drugs on the choroidal blood flow. Methodological considerations will be analyzed, such as the calculation of the sensitivity of the experiments, the comparisons of different groups with or without randomization.

Conclusion laser Doppler flowmetry is a useful and a non invasive technique to study the effect of treatment on choroidal blood flow. In ocular disease, investigators should be aware of the tissue scattering changes associated with a retinal or choroidal disease and the necessity of a controlled foveal fixation.
Autoregulation in the choroid
Authors: ORGUL S
Published: September 2009

Purpose To compare subfoveal choroidal blood flow (ChBF) in sitting and supine position in normal volunteers.

Methods ChBF was measured with laser Doppler flowmetry in 22 healthy volunteers (mean age ± SD: 24 ± 5 years). Six independent measurements of choroidal blood flow were obtained in one randomly selected eye of each subject. Subsequently, the subjects assumed a supine position for 30 minutes and a new series of 6 measurements was obtained. Parallel hereto, systemic blood pressure and intraocular pressure were measured. Ocular perfusion pressure (OPP) was calculated based on formulas derived from ophthalmodynamometric studies. The influence of changing OPP on the change in ChBF was assessed in a linear regression analysis.

Results The coefficient of variation for ChBF was 10.28% and 9.58% in the sitting and the supine position respectively. ChBF decreased by 6.6% (p=0.0017) in the supine position. The estimate for ophthalmic blood pressure in the supine position was adjusted to obtain a result of no change in OPP for no change in ChBF, yielding an average decrease for the estimate of OPP of 6.7% (p=0.0002). Change in OPP correlated significantly with change in ChBF (R2: 0.20; p=0.036) with a slope for the regression line of 1.04.

Conclusion The comparable degree of change in ChBF and OPP and the linear relationship between the two parameters suggest a passive response of the choroidal circulation to the posture change. In contrast, the OPP estimates suggest a marked buffering of the change in perfusion pressure by the carotid system, compatible with a close control of the gradient in perfusion pressure between the heart and its branches within the carotid system.
An antibiotic releasing contact lens
Authors: CIOLINO J , HOARE T , IWATA N , BEHLAU I , DOHLMAN CH , LANGER R , KOHANE D
Published: September 2009

Purpose To characterize a drug‐eluting contact lens designed to release ciprofloxacin to the eye in a controlled manner for an extended period of time.

Methods Thin fiilms, containing ciprofloxacin or fluorescein encapsulated in PLGA (Poly[lactic‐co‐glycolic acid]), were coating by pHEMA (poly[hydroxyethyl methacrylate]) by ultraviolet light polymerization, creating prototype contact lenses. The films were characterized by scanning electron microscopy. Release studies were conducted in phosphate buffered saline at 37°C with continuous shaking. Ciprofloxacin eluted from the contact lens was studied in an antimicrobial assay to verify antimicrobial effectiveness.

Results Ciprofloxacin and fluorescein were released from the contact lenses in a controlled manner, demonstrating zero‐order release kinetics under infinite sink conditions for over 4 weeks. The rate of drug release was controlled by modifying either the ratio of drug to PLGA or the molecular weight of the PLGA employed. Both the PLGA and the pHEMA affected release kinetics. Ciprofloxacin released from the contact lenses inhibited ciprofloxacin‐sensitive Staphylococcus aureus at all time‐points tested.

Conclusion A thin drug‐PLGA film coated with pHEMA could potentially be used to create contact lenses which can serve as a platform for ocular delivery of antibiotics and other medications, with widespread therapeutic applications.
Uveitis caused by fastidious bacteria
Authors: BODAGHI B , DRANCOURT M , CASSOUX N , RAOULT D , LEHOANG P
Published: September 2009

Purpose The etiologic evaluation of uveitis is frequently unsuccessful if only noninvasive methods are used. We conducted a prospective study to evaluate systematic screening for pathogens of uveitis.

Methods All patients with uveitis referred to the participating tertiary ophthalmology departments from January 2001 to September 2007 underwent intraocular and serum specimen collection. The standardized protocol for laboratory investigations included universal polymerase chain reaction (PCR)‐based detection of any bacteria and mycoses, specific PCR‐based detection of fastidious (difficult‐to‐grow) bacteria and herpes viruses, and culture of vitreous fluid. Sera were tested for fastidious bacteria.

Results Among the 1321 included patients, infection was diagnosed in 147 (11.1%) patients: 78 (53%) were caused by fastidious bacteria that included spirochetes, Bartonella species, intracellular bacteria (Chlamydia species, Rickettsia species, Coxiella burnetii), and Tropheryma whipplei; 18 by herpes viruses; and 9 by fungi. Bartonella quintana, Coxiella burnetii, Paracoccus yeei, Aspergillus oryzae, and Cryptococcus albidus were found to be associated with uveitis for the first time, to our knowledge.

Conclusion We recommend applying a 1‐step diagnostic procedure that incorporates intraocular, specific microbial PCR with serum analyses in tertiary centers to determine the etiology of uveitis.
Retinal nerve fiber layer and macular thickness measured with Cirrus and Spectralis Fourier‐domain optical coherence tomographies: comparative study in healthy eyes.
Authors: PINILLA I , GARCIA MARTIN E , IDOIPE M , GIL ARRIBAS L , FUERTES MI , FERRERAS A
Published: September 2009

Purpose To compare the retinal nerve fiber layer (RNFL) measurements and macular thickness measurements in healthy eyes using two different Fourier‐domain optical coherence tomographies (OCT) devices: Cirrus HD OCT (Carl Zeiss Meditec, Dublin, Ca) and Spectralis OCT (Heidelberg Engineering, Heidelberg, Germany).

Methods Fifty healthy eyes (33 women and 17 men, aged from 23 to 59 years) were prospectively analysed using 3 optic disc protocols and 3 volume cube scans with each device. Descriptive statistics, analysis of variance and coefficients of variation (COV) were calculated for RNFL average thickness and for the 9 areas corresponding to the Early Treatment Diabetic Retinopathy Study (ETDRS) in macular protocol. Differences between the acquisitions of RNFL quadrants with both devices made them unable to compare.

Results RNFL thickness measurements showed significant differences between Cirrus HD OCT and Spectralis OCT (mean: 98.91 ± 7.39 microns and 102.20 ± 7.93 microns respectively) (p<0.001). Total retinal thickness mean showed significant differences between Cirrus OCT and Spectralis OCT (mean: 269.27 ± 23.25 and 277.79 ± 20.43 microns, respectively) (p=0.032). All measurements were highly reproducible. The retinal COV were from 0.1% (nasal outer ETDRS area) to 2.3% (average thickness) using Cirrus OCT and from 0.1% (nasal outer ETDRS area) to 2.2% (inferior outer ETDRS area) with Spectralis OCT. RNFL average thickness showed lower COV using Cirrus OCT (1.36%) than Spectralis OCT (1.79%).

Conclusion Fourier domain OCTs show differences between their measurements and good reproducibility to analyze RNFL and macular thickness.
Balancing treatment allocations by clinician or center in randomized trials allows unacceptable levels of treatment prediction
Authors: Hills Robert K , Gray Richard , Wheatley Keith
Published: August 2009

Objective Randomized controlled trials are the standard method for comparing treatments because they avoid the selection bias that might arise if clinicians were free to choose which treatment a patient would receive. In practice, allocation of treatments in randomized controlled trials is often not wholly random with various ‘pseudo‐randomization’ methods, such as minimization or balanced blocks, used to ensure good balance between treatments within potentially important prognostic or predictive subgroups. These methods avoid selection bias so long as full concealment of the next treatment allocation is maintained. There is concern, however, that pseudo‐random methods may allow clinicians to predict future treatment allocations from previous allocation history, particularly if allocations are balanced by clinician or center. We investigate here to what extent treatment prediction is possible.

Methods Using computer simulations of minimization and balanced block randomizations, the success rates of various prediction strategies were investigated for varying numbers of stratification variables, including the patient's clinician.

Results Prediction rates for minimization and balanced block randomization typically exceed 60% when clinician is included as a stratification variable and, under certain circumstances, can exceed 80%. Increasing the number of clinicians and other stratification variables did not greatly reduce the prediction rates. Without clinician as a stratification variable, prediction rates are poor unless few clinicians participate.

Conclusion Prediction rates are unacceptably high when allocations are balanced by clinician or by center. This could easily lead to selection bias that might suggest spurious, or mask real, treatment effects. Unless treatment is blinded, randomization should not be balanced by clinician (or by center), and clinician–center effects should be allowed for instead by retrospectively stratified analyses.
Can paying for results help to achieve the Millennium Development Goals? A critical review of selected evaluations of results‐based financing
Authors: Oxman Andrew D , Fretheim Atle
Published: August 2009

Background Results‐based financing (RBF) refers to the transfer of money or material goods conditional on taking a measurable action or achieving a predetermined performance target. RBF is being promoted for helping to achieve the Millennium Development Goals (MDGs).

Methods We undertook a critical appraisal of selected evaluations of RBF schemes in the health sector in low and middle‐income countries (LMIC). In addition, key informants were interviewed to identify literature relevant to the use of RBF in the health sector in LMIC, key examples, evaluations, and other key informants.

Results The use of RBF in LMIC has commonly been a part of a package that may include increased funding, technical support, training, changes in management, and new information systems. It is not possible to disentangle the effects of financial incentives as one element of RBF schemes, and there is very limited evidence of RBF per se having an effect. RBF schemes can have unintended effects.

Conclusion When RBF schemes are used, they should be designed carefully, including the level at which they are targeted, the choice of targets and indicators, the type and magnitude of incentives, the proportion of financing that is paid based on results, and the ancillary components of the scheme. For RBF to be effective, it must be part of an appropriate package of interventions, and technical capacity or support must be available. RBF schemes should be monitored for possible unintended effects and evaluated using rigorous study designs.
Four decades of research on the effects of detracking reform: Where do we stand?—A systematic review of the evidence
Authors: Rui Ning
Published: August 2009

Objective To review and synthesize evidence about academic and non‐academic effects of detracking reform.

Methods Fifteen studies conducted from 1972 to 2006 were located and reviewed, including 4 experimental studies, 2 quasi‐experimental studies, 7 observational studies, and 2 qualitative studies. Meta‐analyses using fixed effects and random effects models were conducted for all and subsets of selected studies (by the academic ability of students and research design), followed by extensive discussion of individual studies.

Results Generally speaking, students in detracked groups performed slightly better academically than their equivalent‐ability peers in tracked groups (d= 0.087, k= 22, N= 15,577, p < 0.0001), using a fixed effects model. A random effects model also indicated the overall positive effects of detracking (d= 0.202, k= 22, N= 15,577, p < 0.01). However, the effect sizes of individual studies are generally heterogeneous with I2(21) = 94.033. Using a random effects model, the study shows that average or high ability students in detracked groups performed no differently than their equivalent‐ability peers in tracked groups with a 95% confidence interval of (−0.047, 0.388). For low‐achieving students, both the fixed effects model [d= 0.113, k= 8, p < 0.0001, 95% CI (0.056, 0.169)] and random effects model [d= 0.283, k= 8, p < 0.005, 95% CI (0.087, 0.479)] revealed positive effects of detracking on student achievement for the 8 low‐ability subgroups in 6 studies. The evidence with respect to the non‐academic impact of detracking is mixed.

Conclusion The findings suggest that the detracking reform had appreciable effects on low‐ability student achievement and no effects on average and high‐ability student achievement. Therefore, detracking should be encouraged, especially in schools where the lower‐track classes have been traditionally assigned fewer resources.
Preparation and response of medical and health institutions when energy flow is interrupted and infrastructure is damaged
Authors: Li Qun , Wu Xiukun , Bai Hong , Chen Hong , Yang Dingjun , Li Shizhou , Duan Liangsong , Zhu Ruiquan , Zhu Haiyang , Yao Jianyi , Xu Zhen , Mao Suling , Yang Weizhong
Published: August 2009

Energy interruption and infrastructure damage are the common characteristic between the snow disaster occurred in some southern provinces of China and the 5.12 Wenchuan earthquake in China in 2008. This paper summaries the effects on medical and health institutions caused by interruption of energy flow and damaged infrastructure, shares the preparation and response practices, experience, and lessons of medical disasters, and gives suggestions about how to prepare and response for medical and health institutions when energy flow is interrupted and infrastructure is damaged.
Investigation into the practice of ensuring a steady blood supply for medical rescue during the Wenchuan Earthquake
Authors: Yi Mei
Published: August 2009

In the rescue that follows a major natural disaster, blood donation is a unique, necessary method to assist the injured. To achieve effective assurance of the blood supply for medical rescue in an orderly fashion, the current procedure must be adjusted by using scientific prediction, analysis, and adaptation. After the process of ensuring the blood supply for medical rescue during the Wenchuan Earthquake, the Ministry of Health of China, with great efforts, continues to investigate and reflect upon the application of the above principals during actual practice. Objectively, these efforts will lead to better results and establish a standard supplying blood during a disaster rescue.
Investigating the Use of Methane as Diesel Fuel in Off-Road Haul Road Truck Operations
Authors: Gurgenci Hal , Aminossadati Saiied M.
Published: September 2009

A scope study is conducted to investigate the technical and commercial feasibility of converting existing mine haul truck engines to a fuel regime of methane and diesel. A dual fuel engine with two technology options of homogeneous gas charge and high pressure direct injection are considered. The results of this study show that cost reduction is only possible when methane is available at a cost saving that compensates for the expense of building a new fuel infrastructure, and a clean combustion is expected. In contrast to diesel-only engines, particulate emissions in dual fuel engines are less. However, unburned methane in the exhaust gases or significant methane leakage must be seriously taken into consideration for replacing diesel with methane. This scope study argues that the dual fuel operation with HGC/CNG technology is expected to be feasible even at a relatively small truck fleet size.
Effects of Si interlayer on resistance switching of Pt/Si/TiO2/Pt structures
Authors: Go Seunghee , Jeong Kyunghoon , Lee Kwanwoo , Kim Ara , Ruh Hyun , Kim Chang Soo , Lee Jaegab
Published: August 2009

In order to improve the resistive switching reliability of devices made using TiO2 grown by atomic layer deposition at 130 °C, a thin Si layer was inserted between the Pt top electrode and the TiO2 thin films. The annealing of the Pt/Si(O)/TiO2/Pt structures at 300 °C in N2 ambient produced Pt/Pt3Si/PtSi particle-embedded SiO2/Ti-silicate/TiO2/Pt multistructures, as confirmed by x-ray diffraction, x-ray photoelectron spectroscopy, and high resolution transmission electron microscopy. The as-annealed multistructures showed enhanced adhesion properties and significantly improved resistive switching performances, especially in terms of the number of the switching cycles and device yield. Based on the analyses, the authors proposed that the interfacial formation of Pt3Si and Ti silicate is responsible for the enhanced adhesion and the improved resistive switching reliability of TiO2 devices result from the enhanced mechanical stability as well as the presence of Ti silicate, which acts as source and sink for defects.
Photoluminescence enhancement by rapid thermal annealing for ZnO epitaxial films grown on Si (100) by pulsed laser deposition
Authors: He Q. , Wang X. N. , Wang H. B. , Zhu J. H. , Wang Hao , Jiang Y.
Published: August 2009

ZnO single-crystalline films were prepared by predepositing a homobuffer layer on Si (100) substrate in a pulsed laser deposition system. The effect of short-time rapid thermal annealing under N2 and O2 ambient on the optical property was systematically studied by photoluminescence measurements from 77K to room temperature. Different from the adverse effect of the O2-assisted rapid thermal annealing on the optical quality, N2-assisted rapid thermal annealing can greatly enhance the ultraviolet emission while eliminate the deep-level emission band including separate green, yellow, and orange luminescence peaks. Such ambient-dependent photoluminescence enhancement was attributed to the elimination of oxygen interstitial in the ZnO film.
Fabrication and optical properties of Ti-doped W18O49 nanorods using a modified plasma-arc gas-condensation technique
Authors: Su Cherng-Yuh , Lin Hsuan-Ching , Lin Chung-Kwei
Published: August 2009

In this study, Ti-doped W18O49 nanorods were prepared without any templates or catalysts using a modified plasma-arc gas-condensation technique. Structure investigations were conducted and the optical properties of the as-prepared nanorods were characterized by field emission gun scanning electron microscope, high-resolution transmission electron microscope, x-ray diffractometer, x-ray photoelectron spectroscope, micro-Raman, and ultraviolet (UV)-visible spectrometers. The experimental results showed that the diameter and the length of the as-prepared nanorods were approximately 20nm and 3μm, respectively. The as-prepared nanorods exhibited W18O49 structures and characteristic Raman peaks could be observed. UV-visible absorption investigations revealed that Ti-doped W18O49 nanorods exhibited a redshift phenomenon when compared with the pure TiO2 and WO3.
Novel heterostructure of CdS nanoparticle/WO3 nanowhisker: Synthesis and photocatalytic properties
Authors: Kim Hyeyoung , Tak Youngjo , Senthil Karuppanan , Joo Jinmyoung , Jeon Sangmin , Yong Kijung
Published: August 2009

A novel heterostructure of CdS nanoparticles/WO3 nanowhiskers was synthesized using a simple two-step process; thermal evaporation and chemical bath deposition. First, WO3 nanowhiskers (NWs) were grown on a tungsten substrate by thermal evaporation of WO3 powder in a tube furnace at 1050°C. Sequentially, CdS nanoparticles (NPs) were deposited on WO3 nanowhiskers by chemical bath deposition. CdS nanoparticles modified WO3 nanowhiskers showed enhanced visible light absorption compared to bare WO3 nanowhiskers. The photocatalytic activity was studied by the photodegradation of methylene blue. CdS NP/WO3 NW heterostructures showed remarkably enhanced photodecomposition efficiencies compared to bare WO3 nanowhiskers.
The effect of acid on superconformal filling in 100nm trenches
Authors: Gallaway Joshua W. , West Alan C.
Published: August 2009

A study is undertaken to determine the effect of low (10g∕L) and high (100g∕L) acid conditions on superconformal copper electroplating. The suppressor used is the surfactant P-104 at 200ppm, with the accelerator bis(3-sulfopropyl)-disulfide (SPS) at a concentration of 5–35ppm. High acid open circuit potential and polarization curves are shifted approximately −30mV from low acid, both with and without P-104; Tafel slopes are the same at ∼100mV/decade. P-104 displays the same suppression strength in both electrolytes. Patterned 100nm trenches show that the rate of high and low acid filling is essentially the same at low SPS concentration (5ppm). As SPS increases, high acid filling is improved; the effect in low acid is inverse, albeit not as strong. As suppression strength is the same in high and low acids, the dependence on SPS during filling is attributed to acceleration, which involves an interaction between suppressor and accelerator molecules.
Combined Inactivation of
lon
and
ycgE
Decreases Multidrug Susceptibility by Reducing the Amount of OmpF Porin in
Escherichia coli
Authors: Duval Valérie , Nicoloff Hervé , Levy Stuart B.
Published: September 2009

Transposon inactivation of
ycgE
, a gene encoding a putative transcriptional regulator, led to decreased multidrug susceptibility in an
Escherichia coli lon
mutant. The multidrug susceptibility phenotype (e.g., to tetracycline and β-lactam antibiotics) required the inactivation of both
lon
and
ycgE
. In this mutant, a decreased amount of OmpF porin contributes to the lowered drug susceptibility, with a greater effect at 26°C than at 37°C.
CytochromecBiogenesis: Mechanisms for Covalent Modifications and Trafficking of Heme and for Heme-Iron Redox Control
Authors: Kranz Robert G. , Richard-Fogal Cynthia , Taylor John-Stephen , Frawley Elaine R.
Published: August 2009

Heme is the prosthetic group for cytochromes, which are directly involved in oxidation/reduction reactions inside and outside the cell. Many cytochromes contain heme with covalent additions at one or both vinyl groups. These include farnesylation at one vinyl in hemesoandaand thioether linkages to each vinyl in cytochromec(at CXXCH of the protein). Here we review the mechanisms for these covalent attachments, with emphasis on the three unique cytochromecassembly pathways called systems I, II, and III. All proteins in system I (called Ccm proteins) and system II (Ccs proteins) are integral membrane proteins. Recent biochemical analyses suggest mechanisms for heme channeling to the outside, heme-iron redox control, and attachment to the CXXCH. For system II, the CcsB and CcsA proteins form a cytochromecsynthetase complex which specifically channels heme to an external heme binding domain; in this conserved tryptophan-rich “WWD domain” (in CcsA), the heme is maintained in the reduced state by two external histidines and then ligated to the CXXCH motif. In system I, a two-step process is described. Step 1 is the CcmABCD-mediated synthesis and release of oxidized holoCcmE (heme in the Fe+3state). We describe how external histidines in CcmC are involved in heme attachment to CcmE, and the chemical mechanism to form oxidized holoCcmE is discussed. Step 2 includes the CcmFH-mediated reduction (to Fe+2) of holoCcmE and ligation of the heme to CXXCH. The evolutionary and ecological advantages for each system are discussed with respect to iron limitation and oxidizing environments.
Molecular Aspects ofMoraxella catarrhalisPathogenesis
Authors: de Vries Stefan P. W. , Bootsma Hester J. , Hays John P. , Hermans Peter W. M.
Published: August 2009

In recent years,Moraxella catarrhalishas established its position as an important human mucosal pathogen, no longer being regarded as just a commensal bacterium. Further, current research in the field has led to a better understanding of the molecular mechanisms involved inM. catarrhalispathogenesis, including mechanisms associated with cellular adherence, target cell invasion, modulation of the host's immune response, and metabolism. Additionally, in order to be successful in the host,M. catarrhalishas to be able to interact and compete with the commensal flora and overcome stressful environmental conditions, such as nutrient limitation. In this review, we provide a timely overview of the current understanding of the molecular mechanisms associated withM. catarrhalisvirulence and pathogenesis.
Lessons in Signaling and Tumorigenesis from Polyomavirus Middle T Antigen
Authors: Fluck Michele M. , Schaffhausen Brian S.
Published: August 2009

The small DNA tumor viruses have provided a very long-lived source of insights into many aspects of the life cycle of eukaryotic cells. In recent years, the emphasis has been on cancer-related signaling. Here we review murine polyomavirus middle T antigen, its mechanisms, and its downstream pathways of transformation. We concentrate on the MMTV-PyMT transgenic mouse, one of the most studied models of breast cancer, which permits the examination of in situ tumor progression from hyperplasia to metastasis.
StreptococcusAdherence and Colonization
Authors: Nobbs Angela H. , Lamont Richard J. , Jenkinson Howard F.
Published: August 2009

Streptococci readily colonize mucosal tissues in the nasopharynx; the respiratory, gastrointestinal, and genitourinary tracts; and the skin. Each ecological niche presents a series of challenges to successful colonization with which streptococci have to contend. Some species exist in equilibrium with their host, neither stimulating nor submitting to immune defenses mounted against them. Most are either opportunistic or true pathogens responsible for diseases such as pharyngitis, tooth decay, necrotizing fasciitis, infective endocarditis, and meningitis. Part of the success of streptococci as colonizers is attributable to the spectrum of proteins expressed on their surfaces. Adhesins enable interactions with salivary, serum, and extracellular matrix components; host cells; and other microbes. This is the essential first step to colonization, the development of complex communities, and possible invasion of host tissues. The majority of streptococcal adhesins are anchored to the cell wall via a C-terminal LPxTz motif. Other proteins may be surface anchored through N-terminal lipid modifications, while the mechanism of cell wall associations for others remains unclear. Collectively, these surface-bound proteins provideStreptococcusspecies with a “coat of many colors,” enabling multiple intimate contacts and interplays between the bacterial cell and the host. In vitro and in vivo studies have demonstrated direct roles for many streptococcal adhesins as colonization or virulence factors, making them attractive targets for therapeutic and preventive strategies against streptococcal infections. There is, therefore, much focus on applying increasingly advanced molecular techniques to determine the precise structures and functions of these proteins, and their regulatory pathways, so that more targeted approaches can be developed.